Transgenic maize, Zea mays L., event TC1507 produces the Cry1F protein to provide protection from feeding by several important lepidopteran pests, including Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae). Reports of reduced field performance against this species in Puerto Rico were investigated, and laboratory bioassays showed that S. frugiperda collected from the affected area exhibited lower sensitivity to the Cry1F protein compared with typical colonies from other regions. The resistance was shown to be autosomally inherited and highly recessive. The Puerto Rico colony was shown to be moderately less sensitive than susceptible laboratory strains to Cry1Ab and Cry1Ac, but the differences in sensitivity were dramatically smaller than for Cry1F. Potential contributory factors to the emergence of resistance to Cry1F in Puerto Rico populations of S. frugiperda include the tropical island geography, unusually large population sizes in 2006, and drought conditions reducing the availability of alternative hosts. In response to this resistance incident, the technology providers have stopped commercial sales of TC1507 maize in Puerto Rico pending potential reversion to susceptibility.

The parasitic mite Varroa destructor Anderson & Trueman (Acari: Varroidae) is arguably the most detrimental pest of the European-derived honey bee, Apis mellifera L. Unfortunately, beekeepers lack a standardized sampling plan to make informed treatment decisions. Based on data from 31 commercial apiaries, we developed sampling plans for use by beekeepers and researchers to estimate the density of mites in individual colonies or whole apiaries. Beekeepers can estimate a colony's mite density with chosen level of precision by dislodging mites from ≈300 adult bees taken from one brood box frame in the colony, and they can extrapolate to mite density on a colony's adults and pupae combined by doubling the number of mites on adults. For sampling whole apiaries, beekeepers can repeat the process in each of n = 8 colonies, regardless of apiary size. Researchers desiring greater precision can estimate mite density in an individual colony by examining three, 300-bee sample units. Extrapolation to density on adults and pupae may require independent estimates of numbers of adults, of pupae, and of their respective mite densities. Researchers can estimate apiary-level mite density by taking one 300-bee sample unit per colony, but should do so from a variable number of colonies, depending on apiary size. These practical sampling plans will allow beekeepers and researchers to quantify mite infestation levels and enhance understanding and management of V. destructor.

Homalodisca vitripennis (Germar) and Spissistilus festinus (Say) populations were surveyed bimonthly for 14 mo in Kern County, CA, at five agricultural sites made up of a variety of potential host plants. In addition, S. festinus populations were surveyed in four alfalfa, Medicago sativa L., fields in Kern and Tulare counties. Insects were collected by beats-sweeps and sticky traps. Data on host plant condition and phenology, and ground cover presence and composition were collected at the five agricultural sites, whereas data on mowing and insecticide use were collected at the four alfalfa sites. Populations of both insects persisted at the five agricultural locations despite insecticide applications applied as part of a H. vitripennis areawide management program and standard commercial operations. Plants colonized by H. vitripennis included eucalyptus (Eucalyptus L'Hér.), jojoba [Simmondsia chinensis (Link) C. K. Schneid.], and citrus (Citrus spp.). Populations of S. festinus were much greater in collections from alfalfa fields than from the five agricultural sites. Insects collected from the five mixed agricultural sites were negative for presence of X. fastidiosa. In laboratory tests, S. festinus did not acquire or transmit X. fastidiosa in tests with infected grape (Vitis spp.) as an acquisition source and grape, almond [Prunus dulcis (Mill.) D.A.Webb], and alfalfa as inoculation hosts. Recommendations for vector control, vegetation management, and targeted monitoring to reduce insect populations and inoculum potential are discussed.

The psyllid Trioza apicalis Förster (Hemiptera: Triozidae) is a serious pest of carrots, Daucus carota L., in Europe. Carrots exhibiting symptoms of psyllid damage were observed in commercial fields in southern Finland in 2008. Symptoms in affected plants included leaf curling, yellow and purple discoloration of leaves, stunted growth of shoots and roots, and proliferation of secondary roots, Mechanisms by which T. apicalis induces symptoms in plants are not understood, and no plant pathogens have yet been associated with this insect, Given recent association of liberibacter with several crops affected by psyllids, an investigation on whether this bacterium is associated with T. apicalis was conducted, Polymerase chain reaction (PCR) primer pairs OA2/OI2c and LsoF/OI2c, specific for 16S rRNA gene from “Candidatus Liberibacter solanacearum,” generated amplicons of 1,168 bp and 1,173 bp, respectively, from DNA extracted from field-collected psyllids (61 and 36.6%, respectively), laboratory-reared psyllids (70 and 33.3%, respectively), field-collected petioles from symptomatic carrots (80 and 55%, respectively), and laboratory-grown carrots (100% for both primer pairs). In contrast, no PCR products were detected in DNA extracted from insect-free plants. The DNA sequences of amplicons of the genes encoding liberibacter 16S rRNA from psyllids and carrots were identical. DNA of the 16S rRNA gene sequences determined from carrots and psyllids were 99.9% identical to analogous sequences of “Ca. L. solanacearum” amplified from several solanaceous crops and the psyllid Bactericera cockerelli (Sulc), a vector of this bacterium, This is the first report of a plant pathogen associated with T. apicalis and the second known psyllid species associated with “Ca. L. solanacearum.”

Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) or “Qfly,” is the most serious horticultural pest in Australia, with a bioclimatic range that extends from the tropical north to the temperate south. Various Australian horticultural exports depend on certification that they originated from B. tryoni-free areas. To eliminate, rather than suppress, B. tryoni in production areas, a sterile insect technique (SIT) campaign directed at B. tryoni has been in operation in southeastern Australia since 1997. Like many other SIT programs around the world, the B. tryoni SIT program relies on fluorescent dust to mark the sterile insects. However, fluorescent dust marking does not provide 100% accuracy in the identification of sterile insects, as required where the aim is to declare regions completely free of fruit fly. Here, we show that novel mitochondrial markers can be introduced into a strain of B. tryoni by interspecies hybridization between B. tryoni and a related but well-differentiated species, Bactrocera jarvisi (Tryon), followed by backcrossing of the hybrid strain with the parental B. tryoni strain. These novel markers do not affect the viability of the strain as measured by pupation and eclosion rates. A simple polymerase chain reaction-based test is described that distinguishes the marked B. tryoni from wild B. tryoni. As required in practice, the test was shown to work reliably on DNA extracted from dead flies that had remained in field traps for up to two weeks.

Tetrastichus planipennisi Yang (Hymenoptera: Eulophidae), a gregarious larval endoparasitoid, is one of three biocontrol agents from Asia currently being released in the United States to combat the invasive emerald ash borer, Agrilus planipennis Fairmaire (Coleoptera: Buprestidae). The current protocol for rearing T. planipennisi involves presenting the wasps with artificially infested ash sticks made by placing field-collected larvae into shallow grooves beneath flaps of bark. Although third and fourth instars are readily accepted by T. planipennisi in these exposures, the suitability of younger or older developmental stages, which are often more readily available in the field, has not been tested. In this study, we used both artificially infested ash sticks and naturally infested ash logs to test which emerald ash borer developmental stages (second to fourth instars, J larvae [preprepupae], prepupae, and pupae) are most suitable for rearing T. planipennisi. T. planipennisi parasitized all stages except for pupae, but parasitized fewer J larvae and prepupae in naturally infested logs than in artificially infested ash sticks. This is probably because, in naturally infested ash logs, these stages were confined to pupal chambers excavated in the sapwood and may have been largely beyond the reach of ovipositing T. planipennisi. The number of T. planipennisi progeny produced was positively correlated (logarithmic) with host weight, but this relationship was stronger when J larvae and prepupae were excluded from the data set. Fourth instars yielded the most parasitoid progeny, followed by, in approximately equal numbers, J larvae, prepupae, and third instars. Second instars yielded too few parasitoid progeny to benefit rearing efforts.

Action thresholds are traditionally based on the density of pests and the economic damage they cause to crops. Pest damage assessments are usually made in a “sterile” environment, devoid of extenuating factors such as predators, parasitoids, and alternative food sources. Recently, the effects of a predator or parasitoid species have been considered. However, interactions between natural enemy species (intraguild predation and interference), which are common in agricultural fields, have not been incorporated yet into decision-making tools. We conducted a series of leaf disc and potted plant trials to evaluate the effects of two predator species, the anthocorid Orius laevigatus (Fieber) and the phytoseiid Neoseiulus cucumeris (Oudemans) on the density of and fruit damage inflicted by western flower thrips, Frankliniella occidentalis (Pergande). We then used the obtained results to develop a pest management decision-making tool for the control of western flower thrips. Because strawberries (Fragaria × ananassa Duchesne) flower in cycles, pollen, a food source for both predators and the pest, is periodically available in the system and has also been incorporated in our decision-making tool. The developed new management tool would allow the relaxation of the economic threshold (ET) for western flower thrips in strawberry flowers. The presence of an average of a single O. laevigatus per flower for example, may allow that relaxation of the ET by 40% (from 10 to 14 western flower thrips per flower) when pollen is available during the winter. Because field monitoring shows that O. laevigatus populations in Israeli strawberry often reach mean densities of three to four per flower, the new approach promises to drastically reduce the employment of toxic insecticides.

We studied the effect of the entomopathogenic fungus Beauveria bassiana strain GHA on a) colony development of the beetles Tribolium castaneum (Herbst) and Ulomoides dermestoides (Fairmaire) (Coleoptera: Tenebrionidae) under laboratory conditions; and 2) the volatile blend released by both beetles, containing defensive pheromones, by using the solid phase microextraction technique. Colony development of both species was strongly altered 3 mo after treatment with B. bassiana, showing a significant reduction in progeny of 37.5% for T. castaneum and 50.0% for U. dermestoides. We also showed that the volatiles released by T. castaneum diminished close to 20% compared with those of healthy beetles, whereas in U. dermestoides secretions dramatically dropped to 5%, 7 d after immersion in 1 × 10⁹ conidia per ml. These results suggest that after infection events take place, fungus-induced diminished secretion of the defensive pheromones may be a physiologic clue for behavioral changes in infected beetles.

Exotic fruit flies (Ceratitis spp.) are often serious agricultural pests. Here, we used pathway analysis and Monte Carlo simulations to assess the risk of introduction of Ceratitis capitata (Wiedemann), Ceratitis cosyra (Walker), and Ceratitis rosa Karsch, into southern China with fruit consignments and incoming travelers. Historical data, expert opinions, relevant literature, and archives were used to set appropriate parameters in the pathway analysis. Based on the ongoing quarantine/ inspection strategies of China, as well as the interception records, we estimated the annual number of each fruit fly species entering Guangdong province undetected with commercially imported fruit, and the associated risk. We also estimated the gross number of pests arriving at Guangdong ports with incoming travelers and the associated risk. Sensitivity analysis also was performed to test the impact of parameter changes and to assess how the risk could be reduced. Results showed that the risk of introduction of the three fruit fly species into southern China with fruit consignments, which are mostly transported by ship, exists but is relatively low. In contrast, the risk of introduction with incoming travelers is high and hence deserves intensive attention. Sensitivity analysis indicated that either ensuring all shipments meet current phytosanitary requirements or increasing the proportion of fruit imports sampled for inspection could substantially reduce the risk associated with commercial imports. Sensitivity analysis also provided justification for banning importation of fresh fruit by international travelers. Thus, inspection and quarantine in conjunction with intensive detection were important mitigation measures to reduce the risk of Ceratitis spp. introduced into China.

Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) is pest of the avocado, Persea americana (Mill.) (Lauraceae), in South Africa and is regarded as a phytosanitary threat. The objective of this study was to develop a systems approach for T. leucotreta on ‘Hass’ avocado that will mitigate the pest risk. T. leucotreta males were monitored with pheromone traps, and numbers declined during the winter. Field studies indicated that most of eggs were laid during January in the Deerpark area, and during harvest, only 0.029 lesions produced live larvae. Survival of larvae in fruit infested on the tree and left to develop after harvest varied and depended on the time of infestation before harvest. Fruit firmness was measured and fifth instars were only present in soft fruit. Fenpropathrin and a granulovirus were effective in reducing the infestation levels. Bags used to cover fruit also reduced infestation levels. Lesions caused by T. leucotreta were visible from two weeks after infestation and fruit with lesions can be sorted. The mean infestation rate per orchard was 0.003 lesions per fruit which makes T. leucotreta on Hass amenable to the alternative treatment efficacy approach and maximum pest limit. In the case of T. leucotreta on Hass, poor host status, production, preharvest and postharvest measures were studied and low infestation levels were observed; all these elements would make a systems approach an option. Furthermore, inspection and certification as well as shipping and distribution measures could be added.

Some phytosanitary irradiation treatment research against tephritid fruit flies (Diptera: Tephritidae) has used artificially infested fruit with the unstated and untested assumption that the method adequately simulated a natural situation. We compare grapefruit, Citrus paradisi Macfayden, naturally infested by Mexican fruit fly, Anastrepha ludens (Loew), via oviposition until larvae reached the late third instar versus insertion of diet-reared third instars into holes made in grapefruits 24 h before irradiation; the latter technique has been used in other studies. Both infestation techniques resulted in statistically indistinguishable results, indicating that insertion of diet-reared third instar Mexican fruit fly into holes bored into grapefruit and subsequently sealed 24 h before irradiation would adequately represent natural infestation and could be used to develop a radiation phytosanitary treatment of the insect in grapefruit when prevention of adult emergence is used as the measure of efficacy. Nevertheless, it may not be advisable to extend this conclusion to other fruit fly/fruit combinations without doing appropriate comparison studies. Dissection of puparia from nonirradiated control insects that failed to emerge as adults showed a relatively even distribution of mortality among the developmental stages within the puparium. In contrast, dissection of puparia from irradiated third instars that did not emerge as adults revealed a sharp attenuation in development from cryptocephalic to phanerocephalic pupae demonstrating this transition to be the developmental step most affected by radiation.

Adult and larval Oryctes rhinoceros (L.) (Coleoptera: Scarabaeidae: Dynastinae) were acoustically detected in live and dead palm trees and logs in recently invaded areas of Guam, along with Nasutitermes luzonicus Oshima (Isoptera: Termitidae), and other small, sound-producing invertebrates and invertebrates. The low-frequency, long-duration sound-impulse trains produced by large, active O. rhinoceros and the higher frequency, shorter impulse trains produced by feeding N. luzonicus had distinctive spectral and temporal patterns that facilitated their identification and discrimination from background noise, as well as from roaches, earwigs, and other small sound-producing organisms present in the trees and logs The distinctiveness of the O. rhinoceros sounds enables current usage of acoustic detection as a tactic in Guam's ongoing O. rhinoceros eradication program.

Inadvertent selection is an important genetic process that frequently occurs during laboratory culture and maintenance of biological control agents and other beneficial organisms used in procedures such as the sterile insect technique (SIT). We investigated effects of mass rearing and inbreeding depression on life history traits (number of progeny emerging from host plants, body weight, developmental period, and starvation tolerance) in the sweetpotato weevil, Cylas formicarius elegantulus (Summers) (Coleoptera: Brentidae). The effect of inbreeding was measured by comparing the results obtained from the full-sib crosses with those obtained from nonkin crosses in both wild and mass-reared strains. The mass-reared strain had more progeny than the wild strain. The developmental period of mass-reared strain was shorter than that of the wild strain. Other traits did not differ significantly between strains. We detected inbreeding depression effects on numbers of progeny, and the effects were more pronounced in the mass-reared strain. Hence, laboratory adaptation to mass rearing can produce changes in important biological attributes of sweetpotato weevils.

The larval feeding requirements and biology of the generalist predatory muscid hunter fly Coenosia attenuata Stein 1903 (Diptera: Muscidae) were investigated at 25°C. Larval C. attenuata were fed second-, third, and fourth-instar (L₂, L₃, and L₄) larvae of the fungus gnat Bradysia impatiens (Johannsen) (Diptera: Sciaridae) at variable rates to determine minimum and optimum numbers of these prey required for normal development. The proportion of C. attenuata larvae surviving to pupation differed significantly as a function of L₂ and L₃ prey numbers. When the number of prey/ d was increased from 10 to 15 L₂ and from 5 to 7 L₃ per day, the respective percentages of pupation increased from 0 to 77% and from 0 to 48%. In contrast, all numbers of L₄ prey (1–7 prey per d) supported pupation, and the pupation rate did not vary with prey number. At the highest prey numbers tested, mortalities of C. attenuata larvae fed L₂, L₃, and L₄ fungus gnat larvae were 7, 30, and 75%, respectively. The higher mortality of larvae fed L₄ prey was clearly the result of lethal wounds inflicted by the fungus gnat larvae in defensive strikes against the predators. At prey numbers supporting maximum rates of adult emergence, larval development required 12–14 d, and duration of the pupal stage was ≈10 d. C. attenuata larvae killed large numbers of prey during their development (means of up to 232 L₂,144 L₃, or 87 L₄ fungus gnats), and larvae provided with marginally inadequate numbers of prey survived for long periods (mean 14–22 d, maximum 34 d) before succumbing to apparent starvation. These are favorable attributes with respect to use of C. attenuata as a biological control agent, suggesting a strong potential to substantially impact high-density pest populations and to survive in low-density pest populations.

The coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae: Scolytinae), is the most important constrain for coffee production throughout the world. Knowledge on the emergence pattern of H. hampei females to infest new berries is crucial to effectively plan control measures. In this laboratory study, we assessed the development of immature stages and the emergence pattern of H. hampei females from the berries by exposing them to temperatures that are typical for high-altitude plantations (≥1,700 m above sea level [masl]) or when coffee is grown under shade trees (20–22°C), and optimum altitude plantations (1,200–1,600 masl) or nonshaded coffee (25–30°C). Fecundity and emergence pattern of H. hampei females from coffee berries varied with temperature. Temperature played a crucial role determining the rate of H. hampei development and therefore the emergence of the females to start a new infestation cycle. The emergence and colonization phases of new colonizing females in coffee plantations with mean temperatures of 20, 25, or 30°C would take place at different moments in the development of the coffee berries, and in some cases more than once. The implications of our findings for an improved, site-specific timing of control interventions against H. hampei are discussed.

Cnaphalocrocis medinalis Guenée (Lepidoptera: Pyralidae) is a major pest in rice, Oryza sativa L. (Graminales: Poaceae), in Asia. The current study investigated the resistance of 17 rice varieties or lines to C. medinalis and behavioral responses of the insect to varieties of different corrected damage ratings (CDRs) and damaged leaves scales (DLSs). The results showed that most varieties (or lines) commonly cultured in rice production were susceptible (DLS 3 and 5) to damage caused by C. medinalis; Yangjing 9538, 91SP, and TN1 were the most susceptible (DLS 7 and 9). A significant positive correlation was observed between CDR and leaf width and chlorophyll content in rice leaves, whereas no significant correlations between resistance and plant height and leaf length were found. The number of eggs laid by C. medinalis adult females significantly increased with CDR. There was a significant difference in the number of eggs laid for varieties of different DLSs. The number laid on varieties of DLS 9 was 44.4, 134.5, and 466.7% greater than DLS 7, 5 and 3, respectively; the number laid on varieties of DLS 7 was 65.5% greater than DLS 5 and 300% greater than DLS 3; and the number laid on those of DLS 5 was 141.7% greater than DLS 3. Developmental duration (day) of larvae, the body length of fifth instar larvae and pupae weight also significantly increased with CDR. A significant difference of to excised leaves was also found among different DLSs with a higher proportion of both first and third instars settled on the leaves of high DLS. Dispersal experiments of larvae on excised leaves showed that the number of first instars that remained settled gradually increased with DLSs. These findings suggested that rice of higher DLS are more suitable for feeding and settling of larvae.

Dispersal and colonization of new areas by armored scale insects (Hemiptera: Diaspididae) is achieved by mobile first-instar nymphs, called crawlers, Few studies have considered the actual mechanisms by which crawlers disperse, and although crawlers are capable of actively wandering over short distances (generally <1 m), their dispersal over longer distances has been thought to be wind-mediated. Here, we present evidence of a potentially more important means of dispersal over longer distances (>1 m). We first confirmed that crawlers of four species of Diaspididae [Abgrallaspis aguacatae Evans, Watson & Miller; Hemiberlesia lataniae (Signoret); Aspidiotus nerii Bouché; and Diaspidiotus perniciosus (Comstock)] have four hairs on the end of each of their legs and that each of these hairs ends in a suction cup-like structure, reminiscent of the attachment structures possessed by phoretic mites. In a controlled environment, using crawlers of A. nerii, we then showed that the crawlers use these structures to attach themselves to three different insect species [Musca domestica L., Cryptolaemus montrozieri Mulsant and Linepithema humile (Mayr)] and can effectively be moved phoretically by these insects. Crawlers can remain attached to flying insects for considerable periods of time, suggesting that this may be an important means of dispersal for armored scale insects. The importance of phoresy for diaspidid dispersal in the field remains to be determined.

The Mexican rice borer, Eoreuma loftini (Dyar) (Lepidoptera: Crambidae), a key pest of sugarcane (Saccharum spp.) and rice, Oryza sativa L., in Texas, has not been controlled with chemical insecticides or biological agents, but some sugarcane varieties have shown degrees of resistance. Assessment of selected sugarcane leaf characteristics indicate that preference for oviposition sites is mostly determined by the presence of a leaf fold and secondarily by the availability of dry leaf tissue, both of which are antixenotic nonchemical stimuli. We suggest that breeding sugarcane lines bearing leaves that do not fold on drying could provide substantial antixenotic resistance against the Mexican rice borer. Previously identified antixenotic chemical stimuli, i.e., low quantities or absence of important nutrients in green leaf tissue, only become apparent when resistant and susceptible sugarcane varieties are compared. Varietal differences in oviposition preference, however, were not observed on excised dry leaf tissue, indicating that expression of resistance in terms of chemical stimuli requires detection of biochemicals in nearby living leaf tissue. Excised dry sugarcane leaves retain the two dominant nonchemical oviposition preference stimuli for Mexican rice borers, and the leaves effectively trapped eggs away from intact plants when dry leaves were used as “mulch” at the bottom of greenhouse cages. Under commercial sugarcane field conditions, bundled dry leaves also collected Mexican rice borer eggs. Possible applications of dry sugarcane leaf substrate for egg scouting and for trapping eggs are discussed.

In 2007, we surveyed the alien and endemic scolytine (bark and ambrosia beetles) fauna of northeastern Ohio, and for the most abundant species, we characterized their seasonal activity and response to three semiochemical baits. In total ,5,339 scolytine beetles represented by 47 species and 29 genera were caught in Lindgren funnel traps. Three species constituted 57% of the total catch, including Xylosandrus germanus (Blandford), Tomicus piniperda (L.), and Diyocoetes autographus (Ratzeburg). Of the total captured, 32% of the species and ≈60% of the individuals were exotic, suggesting that exotic species numerically dominate the scolytine fauna in some urban areas. More native and exotic species were caught in traps baited with ethanol alone than in traps baited with other lures. However, significantly more individuals, especially of T. piniperda, D. autographus, Gnathotrichus materiarius (Fitch), and Ips grandicollis (Eichhoff), and species were caught in traps baited with ethanol plus α-pinene than in traps baited with ethanol alone or the exotic Ips lure. This suggests that among these baits, the ethanol plus α-pinene baits may be useful in maximizing scolytine beetle catches of these species within this region. Species diversity and richness for both native and exotic beetles was greatest in traps baited with ethanol alone. The period of peak trap capture varied depending upon species: X. germanus was most abundant in traps in mid-May and early-August; T. piniperda in mid-May; D. autographus in early June, mid-July, and mid-September; Anisandrus sayi Hopkins and G. materiarius in mid-May, mid-July, and early September; and I. grandicollis in early April, mid-July, and late September.

Plum curculio, Conotrachelus nenuphar (Herbst) (Coleoptera: Curculionidae), adults were exposed to field-aged residues of thiamethoxam, acetamiprid, thiacloprid, indoxacarb, or azinphos-methyl on tart cherry, Prunus cerasus L. variety Montmorency. At 1, 3, 7, and 14 d postapplication, fruit were sampled for chemical residues, and bioassays were used to assess beetle mortality and plant tissue injury. Azinphos-methyl had lethal activity within 1 d of exposure at all postapplication intervals and significant fruit protection extended to 14 d postapplication. All of the neonicotinoids had lethal activity at 3 d posttreatment, with acetamiprid activity extending to 7 d. Antifeedant and oviposition deterrent effects were seen with thiamethoxam and thiacloprid; damage incidence was significantly reduced in the absence of significant beetle mortality or intoxication. Thiamethoxam and acetamiprid penetrated into leaf and fruit tissue and were detected in the interior tissues at 14 d postapplication, but interior thiacloprid residues were not detected after day 1. Indoxacarb provided some fruit protection out to 7 d postapplication, and 14-d-old residues intoxicated beetles, but the slow action of this compound allowed significant damage to occur before beetles were incapacitated. Indoxacarb was only detected as a surface residue after the first day postapplication. These data on the plant— insect—chemistry interactions will support use and management decisions as compounds with acute contact activity are phased out.

Transgenic Bollgard II cotton, Gossypium hirsutum L., expresses Cry1Ac and Cry2Ab proteins that provide control of lepidopteran larvae, including Helicoverpa and Heliothis species (Lepidoptera: Noctuidae) worldwide. Experiments conducted at Katherine, Northern Territory, Australia evaluated the impact of night minimum temperatures on Cry1Ac and Cry2Ab protein levels in Bollgard II cotton. In both 2003 and 2004, potted plants were either grown outside continuously or protected from cold in a glasshouse each night. In 2003, bulked samples of leaves were taken after two periods of low minimum temperature and used to determine a cold-stress threshold and critical period. In 2004, replicated samples were taken on 10 dates spanning five periods of low minimum temperature, allowing analysis of seasonal variation in Cry protein levels. The protein level was markedly higher for Cry2Ab than for Cry1Ac, Cry1Ac protein level peaked midseason and was not adversely affected by minimum temperatures down to 2.6°C. The Cry2Ab protein level remained approximately constant but was reduced by low minimum temperatures (threshold, ≈14°C) for up to 6 d after each chill. The rate of Cry2Ab protein loss was 1.15 and 1.01% per chilling day-degree below threshold in 2003 and 2004, respectively. Impact would seem to be negligible on both the overall efficacy against lepidopteran larvae in-crop and on the current pyramided genes/high-dose/refuge Bt resistance-management strategies because the cold-stress effect is transient, a high level of Cry2Ab protein is still expressed, and there is no impact of chilling on Cry1Ac protein level.

In 2006–2008, we tested (3Z,6Z,9Z,12Z,15Z)-pentacosapentaene (pentaene) with the pheromone components (Z)-11-hexadecenyl acetate (Z11–16:Ac) and (Z)-9-tetradecenyl acetate (Z9–14:Ac), as sex attractants for four sympatric species of coneworms, Dioryctria Zeller (Lepidoptera: Pyralidae) in slash (Pinus elliottii Engelm.) and loblolly pine (Pinus taeda L.) seed orchards in Georgia and Louisiana, respectively. The addition of pentaene increased catches of male southern pine coneworm, Dioryctria amatella (Hulst), in wing traps baited with Z11–16:Ac, whereas catches of Dioryctria disclusa Heinrich in traps baited with Z9–14:Ac were unaffected by the addition of pentaene, The effect of pentaene on male Dioryctria merkeli Mutuura & Munroe was inconsistent. In 2006, pentaene seemed to inhibit attraction of D. merkeli to traps baited with Z9–14:Ac, whereas in a subsequent trial in 2008, moths were equally attracted to Z9–14:Ac with or without the pentaene. We caught too few Dioryctria clarioralis (Walker) in any experiment for meaningful analyses. Our field results with pentaene and the unresolved complexity of the taxonomy, ecology, and management of southern coneworms support the need for a comprehensive examination of the chemical ecology of Dioryctria spp.

Eastern hemlock, Tsuga canadensis (L.) Carrière, branchlets were systemically treated with imidacloprid and bioassayed with hemlock woolly adelgid, Adelges tsugae (Annand) (Hemiptera: Adelgidae), and predators. After 10 d, two hemlock woolly adelgid predators, Laricobius nigrinus Fender (Coleoptera: Derodontidae) and Sasajiscymnus tsugae Sasaji & McClure (Coleoptera: Coc-cinellidae), were allowed to feed on remaining hemlock woolly adelgid for 20 d on branches systemically treated with 1, 10. or 100 ppm imidacloprid. Every 5 d, mortality, mobility (measured as flip time), number of hemlock woolly adelgid consumed, and degree of intoxication of each individual beetle were recorded. Liquid chromatography-mass spectrometry was used to quantify imidacloprid and some of its major metabolites in hemlock wood tissues and in the predator beetles postmortem. Probit analysis of hemlock woolly adelgid mortality and imidacloprid concentrations recovered from branch wood tissues determined the 30 d LC₅₀ to be 242 ppb. A topical application of imidacloprid to the ventral abdomen of individual beetles resulted in a 6 d LD₅₀ value of 1.8 and 0.71 ng imidacloprid per beetle for L. nigrinus and S. tsugae, respectively. In no-choice tests, L. nigrinus mortality was significantly higher on hemlock branchlets treated with 100 ppm imidacloprid than on controls, but S. tsugae mortality was not. S. tsugae consumed the same number of adelgids on treated branchlets as on controls, but L. nigrinus consumed fewer adelgids from the 100 ppm branchlets than on controls. In choice tests, beetle mortality and flip times were generally not significantly different from controls. At times, both beetle species displayed intoxication symptoms after feeding on adelgids from treated branchlets and imidacloprid was recovered from both beetle species postmortem. These results suggest that systemic imidacloprid displayed both lethal and sublethal effects on these two nontarget predators of the hemlock woolly adelgid.

Field assays were performed to determine the optimal color for Agrilus planipennis Fairmaire (Coleoptera; Buprestidae) traps. Previous studies have found that more A. planipennis are caught on purple or green traps than traps of other colors. In three studies, we evaluated various shades of purple, wavelengths of green (500–570 nm), and greens of different reflectance (from 9 to 66%). In all tests, traps of corrugated plastic in standard, commercially available purple (currently used to survey A. planipennis) and a customized green color were used as bases for comparison. Among purple traps, a paint color previously shown to be generally attractive to buprestids caught significantly more A. planipennis adults than traps coated with paints containing more blue or red, or traps constructed of the standard purple plastic. Among traps with maximum reflectance at varying green wavelengths, those ranging in wavelength from 525 to 540 nm caught significantly more adult A. planipennis than traps of other wavelengths. In the 530–540 nm range of the electromagnetic spectrum, there was no significant difference among traps in the 23–66% reflectance range, but traps painted with a peak reflectance of 49% caught more beetles than purple or the custom green plastic traps. Male to female ratio was highest on green traps.

Recapture of marked male codling moths, Cydia pomonella (L.) (Lepidoptera: Tortricidae), released four distances from traps was measured in experiments comparing either lure type or mating disruption. Experiment 1 assessed recapture by 0.1, 1, and 10 mg of codlemone lures, Experiments 2 and 3 assessed moth recapture in orchard plots with 0, 500, or 1,000 Isomate C Plus dispensers per ha. Moths were released 1, 3, 10, and 30 m downwind of the trap in experiments 1 and 2, and 3, 10, 30, and 45 m in experiment 3. Lure type did not affect recapture, however, significantly more moths were recaptured at 3 m compared with 10 or 30 m. Most moths recaptured ≤10 m of the trap were recaptured by day 3, whereas most of the moths recaptured ≥10 m were recaptured after day 3. Thus, 0.1-, 1-, and 10-mg lures, have an attractive range of between 10 and 30 m in orchards lacking mating disruption. Both mating disruption rates greatly reduced moth recapture, and moths recaptured under a 1,000 dispenser per ha rate were recaptured from ≤10 m and within the first 2 d after release. Similar results were observed when release points were expanded to 45 m. Thus, results suggest that pheromone dispenser technologies and placement strategies that maximize disruption of males that arise within 10 m of a female are needed to markedly improve mating disruption.

A series of laboratory and field studies were conducted using three lines of navel orangeworm, Amyelois transitella (Walker) (Lepidoptera: Pyralidae), reared on wheat bran diet and almonds, Prunus dulcis (Mill.) D.A. Webb, at constant and fluctuating temperature. The duration of development on wheat bran diet at constant temperature differed significantly among the three lines. Development was as much as 40% faster at constant temperature than at fluctuating temperatures, consequently the developmental duration determined at constant temperature was not an absolute measure. When the maximum temperature in fluctuating regimes exceeded 43°C, survival decreased by 50% compared with the constant temperature control. In almonds held at constant temperature, the developmental rate on new-crop nuts was variety-dependent and was fastest on ‘Nonpareil’ almonds and slowest on the experimental selection ‘23–122’, Development and survival were also variety-dependent on unharvested (mummy) almonds, and navel orangeworm average emergence was earliest from Nonpareil and latest from ‘Carmel’ nuts, differing by 529 degree-days, whereas survival was the highest on ‘Butte’, 35.7%, and the lowest on Carmel nuts, 7.2%, In our trials, both the speed of development and survival depended on host age, variety and quality, indicating that almonds were a dynamic rather than a static nutrient source for navel orangeworm, Identifying the factors responsible for variation in development and survival will give insight into improving control strategies.

The blueberry gall midge, Dasineura oxycoccana (Johnson) (Diptera: Cecidomyiidae), is a key pest of rabbiteye blueberry, Vaccinium virgatum Aiton, in the southeastern United States, but it has not been studied extensively and little is known about its ecology and management. Studies were conducted to develop an improved method for monitoring D. oxycoccana adults and to determine the within-field distribution of infestation. Four emergence traps were evaluated in an organic rabbiteye blueberry planting for their effectiveness in capturing D. oxycoccana adults early in the season. These traps included a jar trap, wheat blossom midge trap, petri dish trap, and bucket trap. The petri dish and bucket traps captured the highest numbers of adults in 2007 and 2008, respectively. Both traps had a clear plastic panel coated with adhesive. Adult midges emerging from the soil beneath the traps were caught in the adhesive as they flew up toward the light. Emergence traps are useful for detecting the presence of adults early in the season before larval infestation is apparent in the flower buds. To determine the pattern of midge infestation, flower buds were collected weekly from January to March in 2006 from rabbiteye blueberry plants located in a plot at the southwest border of an existing blueberry planting. There were no differences found in the number of larvae collected from various distances within blueberry rows. However, when flower buds were collected from an isolated rabbiteye plot in 2007 and 2008, D. oxycoccana infestation was not uniform. In both years, the southern border row had a significantly higher number of midge larvae per bud compared with the other rows.

Adult and larval wireworm (Coleoptera: Elateridae) populations were surveyed in North Carolina sweetpotato, Ipomoea batatas (L.) Lam., fields during 2005 and 2006 by using yellow sticky traps and larval baits. Eight species of larvae and nine species of adult wireworms were identified. Conoderus vespertinus (F.) was the most prevalent wireworm species, making up 65.9% of the larvae and 62.9% of the adults captured. Adult C. vespertinus were most abundant in July, and larvae were smaller and more abundant after 15 July than earlier in the season, indicating an early summer generation turnover and oviposition in fields planted to sweetpotato. A significant positive relationship was observed between late-season abundance of C. vespertinus and the incidence of wireworm damage. Other wireworm species encountered were Conoderus amplicollis (Gyllenhal), Conoderus bellus (Say), Conoderus falli (Lane), Conoderus lividus (Degeer), Conoderus scissus (Schaeffer), Glyphonyx bimarginatus (Schaeffer), and Melanotus communis (Gyllenhal).

Studies were conducted to determine the residual toxicity of spinetoram, chlorantraniliprole, and emamectin benzoate to obliquebanded leafroller, Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae). Larvae were exposed to apple (Malus spp.) foliage collected at different intervals after an airblast sprayer application at the manufacturer-recommended field rate and half the field rate. A mortality of 100% was recorded at field rate applications of spinetoram, chlorantraniliprole, and emamectin benzoate through 59, 38, and 10 d after treatment (DAT), respectively. Significantly less foliage was consumed by C. rosaceana larvae surviving in the emamectin, chlorantraniliprole, and spinetoram treatments compared with those exposed to untreated foliage. Third-instar C. rosaceana exposed to fresh residues on terminal foliage showed 100% mortality after 5-d exposure to spinetoram residues and after 10-d exposure to chlorantraniliprole and emamectin benzoate. The effects of larval movement from foliage with fresh residues was examined by transferring neonate larvae from foliage treated with spinetoram, chlorantraniliprole, or emamectin benzoate to untreated foliage after various exposure intervals. An exposure of 1, 3, and 6 d was required for spinetoram, chlorantraniliprole, and emamectin benzoate to cause 100% mortality at the field rate, respectively. The higher the concentration of chlorantraniliprole and emamectin benzoate, the less exposure time was necessary to cause high levels of mortality in C. rosaceana neonates. Our results indicate that these novel insecticides are highly toxic to C. rosaceana larvae. Implications of these results for C. rosaceana management programs are discussed.

Tomato flowers (Solanum lycopersicum L.) in greenhouses require assisted pollination. Compared with pollination using a vibration wand, pollination by buzz pollinating bees results in improved seed set and consequently, higher fruit weight. We investigated whether there are further chemical and sensory differences between bee- and wand-pollinated cherry tomatoes, Solanum lycopersicum variety Conchita. The pollination method did not result in significant differences in concentration of soluble solids and titratable acidity. However, the concentration of soluble solids was significantly positively correlated with seed number. We suggest that an increase in the amount of soluble solids in the locular area, due to increased seed numbers, is counteracted by the effects of seed numbers on the growth of the walls, which occurs through cell elongation. In the sensory part of this study, a large, untrained panel significantly preferred bee-pollinated over wand-pollinated tomatoes and classified bee-pollinated tomatoes as having more depth of flavor than wand-pollinated tomatoes. Thus, bee-pollinated tomatoes taste better than wand-pollinated tomatoes, and it is likely that the sensory differences between the two groups of tomatoes are mediated through effects of pollination treatment on seed numbers. Future chemical and sensory studies of fresh tomatoes should take into account the effects of seed numbers and their possible effect on the distribution of chemical compounds within tomatoes.

The toxicity of 10 plant essential oils to adults of acaricide-susceptible, chlorfenapyrresistant (CRT-53), fenpropathrin-resistant (FRT-53), pyridaben-resistant (PRT-53), and abamectinresistant (ART-53) strains of Tetranychus urticae Koch (Acari: Tetranychidae) and to female Neoseiulus californicus McGregor (Acari: Phytoseiidae) was examined using spray or vapor-phase mortality bioassays. In bioassay with the susceptible adults, lemon eucalyptus (19.3 µg/cm³) was the most toxic oil, followed by peppermint, citronella Java, thyme red, caraway seed, clove leaf, and pennyroyal oils (LC₅₀, 20.6–23.7 µg/cm³). The toxicity of these oils was almost identical against adults from either of the susceptible and resistant strains, even though CRT-53, FRT-53, PRT-53, and ART-53 adults exhibited high levels of resistance to chlorfenapyr (resistance ratio [RR], >9,140), fenpropathrin (RR, 94), pyridaben (RR, >390), and abamectin (RR, 85), respectively, Against female N. californicus, lemon eucalyptus (LC₅₀, 21.4 µg/cm³) was the most toxic oil, whereas the LC₅₀ values of the other nine oils ranged from 23.2 to 72.6 µg/cm³. N. californicus was 1–2 times more tolerant than T. urticae to the test essential oils. Thus, these essential oils merit further study as potential acaricides for the control of acaricide-resistant T. urticae populations as fumigants.

Hand-applied dispensers are successfully used in mating disruption programs, but cost of labor to apply these dispensers limits their adoption. Creating hand-applied dispensers that release larger amounts of pheromone and that can be applied at lower densities per hectare could reduce the cost of mating disruption and increase its use. The effect of reducing the number of point sources per hectare while keeping the amount of pheromone applied per hectare constant on the success of Grapholita molesta (Busck) (Lepidoptera: Tortricidae) mating disruption was investigated with Confuse-OFM, paraffin disk, and Isomate-M Rosso dispensers. For all dispensers, as point source density decreased, numbers of moths captured increased, percentage of orientation disruption to traps decreased, and variability in these measures increased. Decreasing point source density, even while keeping the amount of pheromone applied per hectare constant is not a viable option for reducing the cost of G. molesta mating disruption with hand-applied dispensers. Puffers (aerosol dispensers) are applied at 2.5–5 dispensers per ha for G. molesta control. However, hand-applied dispensers fail when clumped at such low numbers of release sites. Potential explanations for the success of Puffers and the failure of hand-applied dispensers at very low point source densities are presented. The utility of paraffin disk dispensers as experimental devices also is discussed.

Cultural practices and insecticide treatments and combinations were evaluated for effect on tuber damage by potato tuberworm, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae) in the Columbia basin of eastern Oregon and Washington. A range of intervals between initial application of several insecticides and vine-kill were tested to determine how early to implement a program to control potato tuberworm tuber damage. Esfenvalerate, methamidophos, and methomyl were applied at recommended intervals, with programs beginning from 28 to 5 d before vine-kill, All insecticide treatments significantly reduced tuber damage compared with the untreated control, but there was no apparent advantage to beginning control efforts earlier than later in the season. Esfenvalerate and indoxacarb at two rates and a combination of the two insecticides were applied weekly beginning 4 wk before and at vine-kill, and indoxacarb was applied at and 1 wk postvine-kill as chemigation treatments. Application of insecticides at and after vine-kill also reduced tuberworm infestation. ‘Russet Norkotah’ and ‘Russet Burbank’ plants were allowed to naturally senesce or were chemically defoliated. They received either no irrigation or were irrigated by center-pivot with 0.25 cm water daily from vine-kill until harvest 2 wk later. Daily irrigation after vine-kill reduced tuber damage, and chemical vine-kill tended to reduce tuber damage compared with natural senescence. Covering hills with soil provides good protection but must be done by vine-kill. Data from these trials indicate that the most critical time for initiation of control methods is immediately before and at vine-kill.

Larvae found infesting fruit from a Carpathian walnut, Juglans regia L., tree in Missouri were confirmed by DNA analysis to be those of pecan weevil, Curculio caryae (Horn) (Coleoptera: Curculionidae). The infested walnut tree occurs in the midst of pecan weevil-infested pecans, Carya illinoinensis (Wang.) K. Koch; the larval haplotypes were found to be identical to pecan weevil larvae from the region, indicating that the walnut infestation arose by association with infested pecan. This is the first confirmed DNA analysis showing pecan weevil attacks J. regia and the second report that J. regia may be at risk of infestation by pecan weevil. Further study indicates this infestation on walnut is established and ongoing. The pecan weevil is a key pest of pecan and seems capable of inflicting similar damage to walnut if spread to commercial areas that produce J. regia.

An action threshold (AT) is one of the most important decision-making elements in integrated pest management. Unlike economic thresholds, ATs are not typically derived from an economic injury level model, but they are more commonly used. ATs may be identified from research-based, pest—crop relationships, but they also may be based on experience. ATs may be adjusted depending on, e.g., weather and plant variety, but modifying ATs to accommodate differences in insecticide efficacy has received little attention. To examine this point, several combinations of ATs and insecticides were evaluated against onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), a major pest of onion (Allium cepa L.). Studies were conducted in New York onion fields from 2006 to 2008 by using registered insecticides for T. tabaci on onions. We hypothesized that the most efficacious insecticides would provide acceptable control of thrips populations regardless of AT (one, three, and five thrips per leaf), whereas less effective products would only control populations using the lowest AT (one thrips per leaf), Results indicated that T. tabaci infestations were managed effectively when spinetoram was applied after a three larvae per leaf threshold, but not when using lambda-cyhalothrin, methomyl or formetanate hydrochloride. However, T. tabaci infestations were managed well when methomyl and formetanate hydrochloride were applied after a one larva per leaf threshold. T. tabaci infestations were never controlled using lambda-cyhalothrin, regardless of the AT used. None of the products reduced T. tabaci populations to an acceptable level when applied at a five larvae per leaf threshold. Implications of adjusting ATs based on efficacy of different insecticides are discussed.

The use of entomopathogens for biological control of subterranean termites (Rhinotermitidae) has attracted attention in the past four decades, and several laboratory studies have shown promising results with fungal agents. This approach was based on the concept of classical biological control with the use of a virulent agent that can self-replicate in a termite nest and be transmitted among individuals, resulting in an epizootic to kill the entire colony. However, the absence of positive results in field studies challenged the potential of fungal pathogens as a realistic approach for subterranean termite control, and the relationship between fungi and subterranean termites remains poorly understood. A multimodal approach of the currently identified defense mechanisms allowed us to show that subterranean termites have the ability to prevent an epizootic from occurring. The defense mechanisms involved in such resistance are reviewed and documented. Finally, the interactions among three major defense mechanisms (grooming, cellular encapsulation, and gut antifungal activity) were analyzed, and it is suggested that these mechanisms act synergistically to produce an efficient defense against the infection of the fungus at the individual and group level so as to protect the colony from epizootics.

Marine vessels have been implicated in the anthropogenic dispersal of invasive termites for the past 500 yr. It has long been suspected that two invasive termites, the Formosan subterranean termite, Coptotermes formosanus Shiraki, and Coptotermes gestroi (Wasmann) (Isoptera: Rhinotermitidae), were introduced to and dispersed throughout South Florida by sailboats and yachts. We compared the distances between 190 terrestrial point records for Formosan subterranean termite, 177 records for C. gestroi, and random locations with the nearest marine dockage by using spatial analysis. Results show that the median distance to nearest docks associated with C. gestroi is significantly smaller than for the random points. Results also reveal that the median distance to nearest docks associated with Formosan subterranean termite is significantly smaller than for the random points. These results support the hypothesis that C. gestroi and Formosan subterranean termite are significantly closer to potential infested boat locations, i.e., marine docks, than random points in these urban areas. The results of our study suggest yet another source of aggregation in the context of exotic species, namely, hubs for pleasure boating.

Field surveys of pest insect pest populations in agroecosystems reveal low but significant levels of tolerance to synthetic and biological pesticides but fail to uncover resistance alleles in test crosses. To study the potential of inducible mechanisms to generate tolerance to synthetic pesticides, we performed baseline susceptibility studies in field and laboratory populations of diamondback moth, Plutella xylostella (L.). to commercial formulations of emamectin benzoate. Pesticide exposure in the field caused elevated levels of tolerance, which decreased in field-collected populations after maintaining insects with pesticide-free diet in the laboratory. Because no significant resistance alleles were identified in back-crossed individuals, the observed increase in tolerance was probably not based on preexisting recessive resistance mechanisms in the population. Instead, the genetic analysis after five and 12 generations is compatible with a transient up-regulation of an immune and metabolic status in tolerant insects that can be transmitted to offspring by a maternal effect. Although the epigenetic effects contributed to incremental increases in tolerance in the first five generations, other resistance mechanisms that are transmitted genetically predominate after 12 generations of increased exposure to the pesticide.

The southern cattle tick, Rhipicephalus (Boophilus) microplus (Canestrini) (Acari: Ixodidae), is a major vector of tick fever organisms affecting cattle in many parts of the world, including Australia, Africa, and South America. Control of the southern cattle tick through acaricide use is an important approach in disease management, Resistance has emerged to many of the acaricides currently and previously used, including the cyclodienes. Although cyclodiene resistance mechanisms have been characterized in many insect species, this report is the first to identify mutations associated with dieldrin resistance in the cattle tick. A novel two base pair mutation in the GABA-gated chloride channel gene has been identified at position 868–9 and causes a codon change from threonine to leucine. Analysis of a small number of field-collected samples resistant to dieldrin shows this mutation has been maintained without selection pressure since the withdrawal of dieldrin in Australia >20 yr ago. The mutation is not found in other laboratory-maintained strains of R. microplus that were subject to selection pressure with various acaricides.

Synergistic effects of verbutin, a member of aryl alkynyl derivatives, to three commonly used acaricides were evaluated with the modified Food and Agricultural Organization Larval Packet Test (FAO-LPT) against both susceptible and resistant strains of the southern cattle tick, Rhipicephalus (Boophilus) microplus (Canestrini) (Acari: Ixodidae). These tick strains demonstrated various levels of resistance to coumaphos (2.5–8.2×), permethrin (57.9–711.7×). and amitraz (3.5–177.5×). Verbutin alone was more toxic to tick larvae than piperonyl butoxide (PBO), a conventional pesticide synergist. With synergism ratios (SRs) ranging from 1.5 to 6.0, verbutin was more potent than PBO (SR = 0.9–1.6) in synergizing coumaphos toxicity to resistant tick larvae. Similarly, verbutin (SR = 1.8–15) was also found to be more potent than PBO (SR = 0.9–2.5) in synergizing amitraz in resistant tick strains. Both verbutin and PBO significantly increased permethrin toxicity to larvae of all tick strains tested, and there was no significant difference between the two synergists. SRs ranged from 2.1 to 4.4 and from 2.1 to 3.6 for PBO and verbutin, respectively.

Colorado potato beetle, Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), has become the economically most important insect defoliator of potatoes, Solanum tuberosum L., in northern Xinjiang Uygur autonomous region in China. Currently, control of Colorado potato beetle relies mainly on chemical insecticides. And this may result in insecticide resistance. In this study, LD₅₀ values were measured by a topical bioassay for 14 conventional insecticides in seven local populations from Urumqi, Changji, Tacheng, Nilka, Gongliu, Qapqal, and Tekes counties (cities). The Tekes field population was the most susceptible population and was selected as a reference strain. Compared with the Tekes strain, the Changji, Qapqal, Nilka, Tacheng, and Gongliu populations exhibited moderate to very high levels of resistance to cyhalothrin. The Qapqal and Changji populations showed a moderate and a very high resistance to deltamethrin, respectively. And the Changji population developed a high resistance against α-cypermethrin. Moreover, the Qapqal population had a moderate resistance to carbofuran, and the Urumqi population reached high level of resistance to endosulfan. Possible resistance mechanisms of the Changji and Qapqal populations were determined using three enzyme inhibitors. Triphenyl phosphate (TPP), diethylmeleate, and piperonyl butoxide (PBO) had little synergism to cyhalothrin in the two populations. In contrast, PBO and TPP exhibited some synergistic effects to carbofuran in the Qapqal population, indicating the involvement of monooxygenases and esterases in conferring carbofuran resistance. It seems that additional mechanisms, such as target site insensitivity, should play an important role in Colorado potato beetle resistances to cyhalothrin and carbofuran in northern Xinjiang local populations.

Previous work demonstrated that methyl palmitate possesses acaricidal activity against Tetranychus viennensis Boisduval (Acari: Tetranychidae) via an unknown mechanism. Here, the symptoms of methyl palmitate toxicity to T. viennensi were studied to determine the acaricidal mechanism of action of this fatty acid methyl ester. Methyl palmitate caused concentration-dependent mortality of T. viennensis, with a moderate concentration (5 mg/ml) eliciting excitement and premature oviposition without spinning shortly after exposure. Tremors of the appendages were subsequently observed, followed by quiescence after ≈5 h. Mites developed dorsal fluid exosmosis at 15–20 h posttreatment with reduced egg production, followed shortly thereafter by death. Some typical neurotoxic symptoms such as excitement and convulsions were observed in methyl palmitateexposed mites, suggesting that methyl palmitate may be a neurotoxin. Compared with other neurotoxic acaricides, methyl palmitate poisoning is a slow process in mites. Transmission electron microscopy revealed serious ultrastructural damage in response to 5 mg/ml methyl palmitate exposure. Autolysis of membranous structures was also observed, especially in the mitochondria, suggesting a novel mode of action for methyl palmitate-induced toxicity.

Obliquebanded leafroller, Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae), is a major pest of pome fruit in Washington. The use of broad-spectrum insecticides for decades has led to the development of insecticide resistance in C. rosaceana. Recently registered insecticides with novel modes of action, such as chlorantraniliprole and spinetoram, have provided effective C. rosaceana control, but resistance remains a threat. The risk of insecticide resistance development in a pest can be assessed by artificial selection in the laboratory. Subsequently, this information can be valuable in developing strategies to retain susceptibility in the field. A laboratory population of C. rosaceana was selected after repeated exposure to chlorantraniliprole and spinetoram to determine the risk of resistance evolution. After six generations of selection, 6.58- and 3.64-fold increases in LC₅₀ were recorded for chlorantraniliprole and spinetoram, respectively. The realized heritability (h²) of resistance was estimated as 0.17 for chlorantraniliprole and 0.18 for spinetoram by using threshold trait analysis. The rates of resistance development were compared using the response quotient (Q), which was estimated as 0.11 and 0.07 for chlorantraniliprole and spinetoram, respectively. Projected rates of resistance evolution indicated that if h² = 0.2 and 80% of the population was killed at each generation, then a 10-fold increase in LC₅₀ would be expected in less than six generations for chlorantraniliprole and 10 generations for spinetoram. These results indicate that the risk of resistance development in C. rosaceana exists to both of these insecticides but that resistance development in C. rosaceana would be slower against spinetoram than chlorantraniliprole.

The study of fitness costs associated with resistance to toxins from Bacillus thuringiensis Berliner (Bt) in Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae) is important for understanding resistance evolution and for evaluating resistance management practices that prevent or mitigate resistance to transgenic corn, Zea mays L. Resistant individuals identified from a field collection in Kandiyohi, MN, were used to generate a Cry1Ab-resistant strain. We used susceptible and resistant strains with similar genetic background to establish crosses and estimate dominance of fitness costs by measuring fitness components and population parameters determined by fertility life tables. Spermatophore volume and mating frequency also were compared to identify potential effects of resistance on fertility. Inheritance of fitness costs in O. nubilalis varied from recessive to incompletely recessive among the parameters evaluated. Selection for resistance to Cry1Ab significantly reduced the fitness of O. nubilalis. Resistant insects exhibited reduced pupal weight and increased developmental time compared with susceptible and F₁ larvae derived from reciprocal crosses of resistant and susceptible parents. In addition, it was observed that resistant insects exhibited a higher proportion of unsuccessful matings and lower fertility than the susceptible strain. Despite the differences observed in resistant insects, our results did not indicate strong evidence of fitness costs in the F₁ progeny.

The U.S. Environmental Protection Agency (USEPA) requires the use of nontransgenic refuges to slow the evolution of insect resistance to transgenic crops. In-field refuges, or refuges that are planted within the same field as the transgenic crop, are allowed; however, these refuges are required to be at least four rows wide. We described in-field planting patterns used by growers for both Cry1Ab [against Ostrinia nubilalis (Hübner)] and Cry3Bb (against Diabrotica virgifera virgifera LeConte) maize, Zea mays L. Maize fields known to contain Cry1Ab, Cry3Bb, or both were sampled in southwestern Minnesota during late June and early September 2005. Rows were sampled to describe the pattern of in-field refuges in the entire field, Most in-field refuges contained >20% Cry^- seed (79% of Cry1Ab and 84% of Cry3Bb). However, only 5% of Cry1Ab fields and 2% of Cry3Bb fields with in-field refuges were in compliance with USEPA requirements because the Cry^- seed was not in wide enough strips or blocks. Most growers had planted their fields with either finely mixed refuges or with strips that were too narrow. There was a high diversity in planting patterns, and the occurrence of Cryseed was in random rows. Growers may have been rushed while planting and not noticed which seed was going into which rows, Resistance failures have not been documented for either O. nubilalis or D. virgifera virgifera, so better education programs will need to be undertaken to encourage growers to plant in-field refuges properly.

The responses to chlorpyrifos of six populations of citricola scale, Coccus pseudomagnoliarum (Kuwana) (Hemiptera: Coccidae), were tested using a leaf dip bioassay, and two- to nine-fold resistances were found. LC₅₀ responses of nymphs ranged from 7.5 to 68.9 ppm and LC₉₀ responses ranged from 20 to 222 ppm chlorpyrifos. A population tested monthly during August-October showed up to 3.5-fold differences in LC₅₀ responses but no differences in LC₉₀ responses as scale size increased. A diagnostic concentration of 178 ppm chlorpyrifos was used to test 93 populations from throughout the San Joaquin Valley California during 2006–2009 by using a leaf dip bioassay. Of the populations tested, 41% showed >20% survival after exposure to the diagnostic concentration of chlorpyrifos, indicating resistance problems. Research is needed to relate the level of survival of the scales in the bioassay to the field efficacy of the insecticide. Tulare County citrus growers applied a higher number of organophosphate and carbamate insecticides during the 15-yr period from 1994 to 2008, and these orchards showed a higher average scale survival of chlorpyrifos and a higher number of locations with resistant scale compared with the other San Joaquin Valley counties. Chlorpyrifos resistance is a significant issue for citricola scale management because biological control is ineffective in the San Joaquin Valley and the alternative neonicotinoid and insect growth regulator (IGR) insecticides require more frequent application.

We evaluated selected soybean, Glycine max (L.) Merr., genotypes during their reproductive stages for resistance to the soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), under greenhouse conditions and documented the categories of aphid-resistant soybean. Two screening studies were performed to assess the level of resistance to the soybean aphid on six soybean genotypes during the reproductive stages of development. Significant differences in aphid damage ratings were detected among the soybean evaluated in the screening studies. Three genotypes (KS4202, K-1639-2, and K1621) were considered moderately resistant based on the assessed damage ratings. Two of these genotypes (K-1639-2 and KS4202), along with a commercial variety (‘Asgrow 2703’) were used in a follow-up greenhouse study to test for antibiosis and tolerance. For the antibiosis evaluation, KS4202 had significantly more nymphs than Asgrow 2703 and K-1639-2. In fact, KS4202 had a threefold difference in the number of nymphs compared with Asgrow 2703 (81.8 ± 14.7 and 26.2 ± 13.9 nymphs, respectively) and a fivefold difference compared with K-1639-2 (15.6 ± 13.9). Although not significant, Asgrow 2703 had more nymphs than K-1639-2. The lower aphid numbers on infested K-1639-2 plants compared with aphid numbers on Asgrow 2703 and KS4202 plants indicates antibiosis for this genotype. No significant differences in average seed weight, number of seeds per pod, or plant damage were observed between infested and control KS4202 plants; however, significant differences in biomass, total seed weight, number of pods per plant, and number of seeds per plant were detected.

The Asiatic rice borer, Chilo suppressalis (Walker) (Lepidoptera: Crambidae), is one of the most destructive pests in rice, Oryza sativa L., throughout Asian countries. The aim of this study was to investigate the potential of applied silicon in mediating rice plant resistance to C. suppressalis in a susceptible (Shanyou63) and a moderately resistant (Yanfeng47) rice cultivar. Silicon-treated plants showed significant increases in silicon content compared with the control. Silicon addition significantly decreased borer penetration, weight gain, and stem damage, and it prolonged penetration duration and larval development; some of the effects were manifested more strongly in the susceptible rice cultivar compared with the moderately resistant cultivar. Therefore, silicon amendment may contribute to the suppression of C. suppressalis directly through reduced feeding damage and performance and indirectly through increased exposure time of young larvae to natural enemies and control measures.

The use of resistant cultivars is a key component of any integrated pest management (IPM) program. Here, we assess the resistance status of 10 different soybean cultivar seeds according to their effects on demographic and nutritional indices of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) when incorporated into artificial diets. All experiments were conducted at 25 ± 1°C, 60 ± 5% RH, and a photoperiod of 16:8 (L:D) h. Life table, reproduction, development, adult longevity, and nutritional indices of H. armigera were significantly affected by the cultivars examined. Mean developmental time of across all immature stages varied from 57 d on ‘L17’ to 32 d on ‘Clark’, Efficiency of conversion of digested food (ECD) for old larvae ranged from 36.4% on ‘Sari’ to 14.8% on ‘Sahar’. The adults that emerged from these larvae had very different rates of reproduction; the highest and lowest values for net reproductive rate (R₀) were 270 and 17 on Clark and L17, respectively. The most important demographic parameter, intrinsic rate of increase (r_m), ranged from 0.114 on Sari to 0.09 on L17. H. armigera did not perform well on Sahar, L17, ‘Gorgan3’, and ‘M4’, These cultivars show antibiosis resistance compared with other tested cultivars and are key candidates for field tests to determine usefulness in an IPM system.

Sugarcane (Saccharum spp.) in Louisiana is colonized by two aphid species, the sugarcane aphid, Melanaphis sacchari (Zehntner), and the yellow sugarcane aphid, Sipha flava (Forbes) (Hemiptera: Aphididae). The main problem associated with M. sacchari is transmission of sugarcane yellow leaf virus, a casual agent of yellow leaf disease whose absence has been added to certification standards for micropropagated sugarcane in Louisiana. Greenhouse studies were conducted to categorize dominant commercial sugarcane cultivars for their ability to tolerate aphid injury and to express antixenotic or antibiotic effects on both aphid species. Antixenosis tests showed no preference among cultivars by either aphid species. Loss of chlorophyll content in tolerance tests also did not show differences among cultivars for both aphid species. However, antibiosis tests revealed that life history parameters such as the duration of the reproductive period and fecundity of both aphid species were negatively affected on ‘HoCP 91-555’ compared with ‘L 97-128’, Estimation of demographic statistics indicated that both aphid species exhibited a significantly lower intrinsic rate of increase (1.8–2.8-fold) and longer doubling time (1.7–3.1-fold) on HoCP 91-555 relative to L 97–128. From these tests, cultivars in the current study can be ranked from most to the least susceptible as L 97–128 > ‘LCP 85–384’ > ‘HoCP 96–540’ > ‘Ho 95–988’ > HoCP 91–555 for M. sacchari and L 97–128 > LCP 85–384 > HoCP 91–555 for S. flava. Therefore, antibiosis is an important category of resistance in sugarcane to both aphid species, and HoCP 91–555 might provide useful germplasm for developing aphid resistant cultivars.

Coffee (Coffea spp.) alkaloids (caffeine and related methylxanthines) and phenolics (caffeic and chlorogenic acids) have recognized pestistatic/pesticidal activity and mediate insect—plant interactions. The present investigation assessed the resistance of 12 coffee genotypes to the leaf miner Leucoptera (=Perileucoptera) coffeella (Guérin-Méneville & Perrottet) (Lepidoptera: Lyonetiidae) and correlated such results with the leaf content of coffee alkaloids and phenolics that probably play a role in the interaction between coffee and this leaf miner. The levels of chlorogenic and caffeic acid, caffeine, and related methylxanthines were measured and quantified in leaf extracts of these genotypes before and 7 d after their infestation by the leaf miner. Some coffee genotypes (Coffea canephora L. and Coffea racemosa Lour. and its hybrids with Coffea arabica L.) exhibited high pesticidal activity (100% mortality) toward the L. coffeella, indicating their antibiosis resistance. However, there was no correlation between this activity and the leaf levels of coffee alkaloids and phenolics. Curiously, infestation by L. coffeella leads to a nearly four-fold decline in the leaf levels of chlorogenic acid, which does not affect this pest species but may affect other generalist species. Indeed, chlorogenic acid sprayed on coffee leaves stimulated locomotory activity of the green scale Coccus viridis (Green) (Hemiptera: Coccidae), thus minimizing their feeding in contrast with the absence of this polyphenol. Therefore, reduction of chlorogenic acid levels in coffee leaves due to leaf miner infestation seems to also favor infestation by generalist insects, such as the green scale.

Six transgenic rice, Oryza sativa L. lines (G6H1, G6H2, G6H3, G6H4, G6H5, and G6H6) expressing a fused Cry1Ab/Vip3H protein, were evaluated for resistance against the Asiatic rice borer, Chilo suppressalis (Walker) (Lepidoptera: Crambidae), and the stem borer Sesamia inferens (Walker) (Lepidoptera: Noctuidae) in the laboratory and field. The bioassay results indicated that the mortality of Asiatic rice borer and S. inferens neonate larvae on six transgenic lines from seedling to filling stage was up to 100% at168 h after infestation. The cumulative feeding area by Asiatic rice borer neonate larvae on all transgenic lines was significantly reduced compared with the untransformed parental ‘Xiushui 110’ rice. A 2-yr field evaluation showed that damage during the vegetative stage (deadheart) or during the reproductive stage (whitehead) caused by Asiatic rice borer and S. inferens for transgenic lines was much lower than the control. For three lines (G6H1, G6H2, and G6H6), no damage was found during the entire growing period. Estimation of fused Cry1Ab/Vip3H protein concentrations using PathoScreen kit for Bt-Cry1Ab/1Ac protein indicated that the expression levels of Cry1Ab protein both in main stems (within the average range of 0.006–0.073% of total soluble protein) and their flag leaves (within the average range of 0.001–0.038% of total soluble protein) were significantly different among six transgenic lines at different developmental stages. Both laboratory and field researches suggested that the transgenic rice lines have considerable potential for protecting rice from attack by both stem borers.

Nineteen isolates of the cereal aphid pest greenbug, Schizaphis graminum (Rondani) (Hemiptera: Aphididae), were collected from wheat, Triticum aestivum L.; barley, Hordeum vulgare L.; or noncultivated grass hosts in five locations from Colorado and Wyoming. Parthenogenetic colonies were established. Biotypic profiles of the 19 isolates were determined based on their abilities to damage a set of host plant differentials, and 13 new biotypes were identified. Genetic diversity among the 19 isolates and five previously designated greenbug biotypes (E, G, H, I, and K) was examined with 31 cross-species transferable microsatellite (simple sequence repeat) markers. Neighbor-joining clustering analysis of marker data revealed host-adapted genetic divergence as well as regional differentiation of greenbug populations. Host associated biotypic variation seems to be more obvious in “agricultural biotypes,” whereas isolates collected from noncultivated grasses tend to show more geographic divergence. It seems that the biotype sharing the most similar biotypic profiles and the same geographic region with current prevailing one may have the greatest potential to become the new prevailing biotype. Close monitoring of greenbug population dynamics especially biotypic variation on both crop plants and noncultivated grasses in small grain production areas may be a useful strategy for detecting potentially new prevailing virulent biotypes of the greenbug.

The western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), is the key pest of corn, Zea mays L., in North America. The western corn rootworm variant is a strain found in some parts of the United States that oviposits in soybean, Glycine max (L.) Merr., thereby circumventing crop rotation. Soybean herbivory is closely associated with oviposition; therefore, evidence of herbivory could serve as a proxy for rotation resistance. A digital image analysis method based on the characteristic green abdominal coloration of rootworm adults with soybean foliage in their guts was developed to estimate soybean herbivory rates of adult females. Image analysis software was used to develop and apply threshold limits that allowed only colors within the range that is characteristic of soybean herbivory to be displayed. When this method was applied to adult females swept from soybean fields in an area with high levels of rotation resistance, 54.3 ± 2.1% were estimated to have fed on soybean. This is similar to a previously reported estimate of 54.8%. Results when laboratory-generated negative controls were analyzed showed an acceptably low frequency of false positives. This method could be developed into a management tool if user-friendly software were developed for its implementation. In addition, researchers may find the method useful as a rapid, standardized screen for measuring frequencies of soybean herbivory.

The seasonal density fluctuations of the carob moth, Ectomyelois ceratoniae (Zeller) (Lepidoptera: Pyralidae), were determined in a commercial date, Phoenix dactylifera L. garden. Four fruit categories (axil, ground, abscised green, and abscised brown) were sampled, and two carob moth life stages, eggs and immatures (larvae and pupae combined), were evaluated on these fruits. Based on the relative consistency of these eight sampling units (four fruit categories and two carob moth stages), four were used for the development of a binomial sampling plan. The average number of carob moth eggs and immatures on ground and abscised brown fruit was estimated from the proportion of infested fruit, and these binomial models were evaluated for model fitness and precision. These analyses suggested that the best sampling plan should consist of abscised brown dates and carob moth immatures by using a sample size of 100 dates. The performance of this binomial plan was evaluated further using a resampling protocol with 25 independent data sets at action thresholds of 7, 10, and 15% to represent light, medium and severe infestations, respectively. Results from the resampling program suggested that increasing sample size from 100 to 150 dates improved the precision of the binomial sampling plan. Use of this sampling plan will be the cornerstone of an integrated pest management program for carob moth in dates.

The soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is currently the most important insect threat to soybean, Glycine max (L.) Merr., production in the North Central United States. Field cage studies are a key tool in investigating the potential of natural enemies and host plant resistance to control this pest. However, a major constraint in the use of cage studies is the limited number of treatments and replicates that can be used as aphid densities frequently become so large as to limit the number of experimental units that can be quantified. One way to overcome this limitation is to develop methods that estimate whole-plant aphid densities based on a reduced sampling plan. Here, we extend an existing method, node-sampling, used for estimating aphid populations in open field conditions and apply it to caged populations. We show that parameters calculated under open field conditions are inappropriate to estimate caged populations. In contrast, using four independent data sets of caged populations and a cross-validation technique, we demonstrate that a three-node sampling unit and a weighted formula provide accurate and robust estimates of whole-plant aphid density. This method reduced the number of aphids counted per plant by and average of 60%, with greater reductions at higher aphid densities. We further demonstrate that nearly identical statistical results were obtained when whole-plant or node-sampling estimates were used in the analysis of two case studies. The reduced sample unit method developed here saves time without sacrificing efficiency so that more plants, replications, or studies can be conducted that will lead to improved soybean aphid management.

“Sweetpotato weevils” Cylas puncticollis (Boheman) and Cylas brunneus F. (Coleoptera: Brentidae) are the most important biological threat to sweetpotato, Ipomoea batatas L. (Lam), productivity in sub-Saharan Africa. Sweetpotato weevil control is difficult due to their cryptic feeding behavior. Expression of Cylas-active Bacillus thuringiensis (Bt) Cry proteins in sweetpotato could provide an effective control strategy. Unfortunately, Bt Cry proteins with relatively high toxicity against Cylas spp. have not been identified, partly because no published methodology for screening Bt Cry proteins against Cylas spp. in artificial diet exists. Therefore, the initial aim of this study was to develop an artificial diet for conducting bioassays with Cylas spp. and then to determine Bt Cry protein efficacy against C. puncticollis and C. brunneus by using this artificial diet. Five diets varying in their composition were evaluated. The highest survival rates for sweetpotato weevil larvae were observed for diet E that contained the highest amount of sweetpotato powder and supported weevil development from first instar to adulthood, similar to sweetpotato storage roots. Seven coleopteranactive Bt Cry proteins were incorporated into diet E and toxicity data were generated against neonate C. puncticollis and second-instar C. brunneus. All Bt Cry proteins tested had toxicity greater than the untreated control. Cry7Aa1, ET33/34, and Cry3Ca1 had LC₅₀ values below 1 µg/g diet against both species. This study demonstrates the feasibility of using an artificial diet bioassay for screening Bt Cry proteins against sweetpotato weevil larvae and identifies candidate Bt Cry proteins for use in transforming sweetpotato varieties potentially conferring field resistance against these pests.

The Indianmeal moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), is a common pest of stored corn, Zea mays L. We developed a computer model to simulate population development of the Indianmeal moth in stored corn by using previously published data describing immature developmental times and survivorship, and adult longevity and fecundity. The model accurately simulated population development of Indianmeal moths in corn stored during fall and into winter of three separate storage seasons in South Carolina. This is the period when the Indianmeal moth is a pest in stored corn in South Carolina. The model predicted that populations would increase after winter as grain temperatures rose, but observed populations in the grain bins never increased after winter. Despite this, the model should be useful from a management perspective because the corn is being sold off or used up after winter, and the observed Indianmeal moth populations never reached damaging levels after winter.

In laboratory experiments, a flameless catalytic infrared emitter, fueled by propane, was used to disinfest hard red winter wheat, Triticum aestivum L., containing different life stages of the lesser grain borer, Rhyzopertha dominica (F.), an economically important insect species associated with stored wheat in Kansas. The emitter generates infrared radiation in the 3–7-µm range. The life stages of R. dominica exposed to infrared radiation included eggs, larvae in different stages of development, pupae, and 2-wk-old adults. A noncontact infrared thermometer measured grain temperatures continuously during exposures of infested wheat to infrared radiation. The grain temperatures attained were influenced by wheat quantity; distance from the emitter; and exposure time, which in turn influenced effectiveness against various life stages of R. dominica. In general, higher grain temperatures were attained in 113.5 g of wheat as opposed to 227.0 g, and at 8.0 cm from the emitter surface rather than at 12.7 cm, and during a 60-s exposure compared with a 45-s exposure. Logistic regression indicated the probability of death of various life stages of R. dominica was temperature dependent. The log odds ratios showed old larvae were less susceptible to infrared radiation than young larvae. Approximately ≥94% mortality of all R. dominica life stages occurred when using 113.5 g of wheat, exposed for 60 s at a distance of 8.0 cm from the emitter, resulting in mean ± SE wheat temperatures that ranged between 107.6 ± 1.4 and 113.5 ± 0.5°C. Our results with small grain quantities show flameless catalytic infrared technology to be a promising tool for disinfestation of stored wheat.