Theory indicates that landscape composition affects transmission of vector-borne crop diseases, but few empirical studies have investigated how landscape composition affects plant disease epidemiology. Since 2006, Bemisia tabaci (Gennadius) has vectored the cucurbit yellow stunting disorder virus (CYSDV) to cantaloupe and honeydew melons (Cucumis melo L.) in the southwestern United States and northern Mexico, causing significant reductions in yield of fall melons and increased use of insecticides. Here, we show that a landscape-based approach allowing simultaneous assessment of impacts of local (i.e., planting date) and regional (i.e., landscape composition) factors provides valuable insights on how to reduce crop disease risks. Specifically, we found that planting fall melon fields early in the growing season, eliminating plants germinating from seeds produced by spring melons after harvest, and planting fall melon fields away from cotton and spring melon fields may significantly reduce the incidence of CYSDV infection in fall melons. Because the largest scale of significance of the positive association between abundance of cotton and spring melon fields and CYSDV incidence was 1,750 and 3,000 m, respectively, reducing areas of cotton and spring melon fields within these distances from fall melon fields may decrease CYSDV incidence. Our results indicate that landscape-based studies will be fruitful to alleviate limitations imposed on crop production by vector-borne diseases.

The North American Plant Protection Organization (NAPPO) is an organization comprising plant protection regulatory officials of the three signatory countries: the United States, Canada, and México. NAPPO develops Regional Standards for Phytosanitary Measures (RSPMs) as well as discussion papers on important issues related to plant protection. The Fruit Panel of NAPPO organized a Technical Assistance Group (TAG) to develop a discussion paper on the status of pest species of Rhagoletis (Diptera: Tephritidae) within the NAPPO countries. As regulations are developed to prevent the spread of these pests both within and outside of the NAPPO countries, it was important to understand the pest status of these species. This article reviews the basic biology, host range, distribution, potential to spread, management, and regulatory status of pest species of Rhagoletis within the NAPPO countries.

Research on threats to pollination service in agro-ecosystems has focused primarily on the negative impacts of land use change and agricultural practices such as insecticide use on pollinator populations. Insecticide use could also affect the pollination process, through nonlethal impacts on pollinator attraction and postpollination processes such as pollen viability or pollen tube growth. Hybrid onion seed (Allium cepa L., Alliaceae) is an important pollinator-dependent crop that has suffered yield declines in California, concurrent with increased insecticide use. Field studies suggest that insecticide use reduces pollination service in this system. We conducted a field experiment manipulating insecticide use to examine the impacts of insecticides on 1) pollinator attraction, 2) pollen/stigma interactions, and 3) seed set and seed quality. Select insecticides had negative impacts on pollinator attraction and pollen/stigma interactions, with certain products dramatically reducing pollen germination and pollen tube growth. Decreased pollen germination was not associated with reduced seed set; however, reduced pollinator attraction was associated with lower seed set and seed quality, for one of the two female lines examined. Our results highlight the importance of pesticide effects on the pollination process. Overuse may lead to yield reductions through impacts on pollinator behavior and postpollination processes. Overall, in hybrid onion seed production, moderation in insecticide use is advised when controlling onion thrips, Thrips tabaci, on commercial fields.

Recent scientific literature and reports from official sanitary agencies have pointed out the deficiency of current pesticide risk assessment processes regarding sublethal effects on pollinators. Sublethal effects include troubles in learning performance, orientation skills, or mobility, with possible contribution to substantial dysfunction at population scale. However, the study of sublethal effects is currently limited by considerable knowledge gaps, particularly for the numerous pollinators other than the honey bee Apis mellifera L.—the traditional model for pesticide risk assessment in pollinators. Here, we propose to use the crop-emptying time as a rule of thumb to guide the design of oral exposure experiments in the honey bee and wild bees. The administration of contaminated sucrose solutions is typically followed by a fasting time lapse to allow complete assimilation before the behavioral tests. The fasting duration should at least encompass the crop-emptying time, because no absorption takes place in the crop. We assessed crop-emptying rate in fasted bees and how it relates 1) with sucrose solution concentration in the honey bee and 2) with body mass in wild bees. Fasting duration required for complete crop emptying in honey bees fed 20 µl of a 50% sucrose solution was nearly 2 h. Actual fasting durations are usually shorter in toxicological studies, suggesting incomplete crop emptying, and therefore partial assimilation of experimental solutions that could imply underestimation of sublethal effects. We also found faster crop-emptying rates in large wild bees compared with smaller wild bees, and suggest operative rules to adapt sublethal assessment schemes accordingly.

Centrifugation of Apis mellifera L. drone semen is a necessary step in the homogenization of semen pools for the enlargement of the effective breeding population, as well as in the collection of semen by the so-called washing technique. It is also of interest for the removal of cryoprotectants after cryopreservation. The adoption of methods involving semen centrifugation has been hampered by their damaging effect to sperm. Here, we tested four new diluents as well as three additives (catalase, hen egg yolk, and a protease inhibitor), using sperm motility and dual fluorescent staining as indicators of semen quality. Three of the new diluents significantly reduced motility losses after centrifugation, as compared with the literature standard. Values of motility and propidium iodide negativity obtained with two of these diluents were not different from those measured with untreated semen. The least damaging diluent, a citrate-HEPES buffer containing trehalose, was then tested in an insemination experiment with centrifuged semen. Most queens receiving this semen produced normal brood, and the number of sperm reaching the storage organ of the queen was not significantly different from that in queens receiving untreated semen. These results could improve the acceptance of techniques involving the centrifugation of drone semen. The diluent used in the insemination experiment could also serve as semen extender for applications not involving centrifugation.

The aim of this study was to improve cage systems for maintaining adult honey bee (Apis mellifera L.) workers under in vitro laboratory conditions. To achieve this goal, we experimentally evaluated the impact of different cages, developed by scientists of the international research network COLOSS (Prevention of honey bee COlony LOSSes), on the physiology and survival of honey bees. We identified three cages that promoted good survival of honey bees. The bees from cages that exhibited greater survival had relatively lower titers of deformed wing virus, suggesting that deformed wing virus is a significant marker reflecting stress level and health status of the host. We also determined that a leakand drip-proof feeder was an integral part of a cage system and a feeder modified from a 20-ml plastic syringe displayed the best result in providing steady food supply to bees. Finally,wealso demonstrated that the addition of protein to the bees' diet could significantly increase the level of vitellogenin gene expression and improve bees' survival. This international collaborative study represents a critical step toward improvement of cage designs and feeding regimes for honey bee laboratory experiments.

Lygus hesperus Knight (Hemiptera: Miridae) is a key agricultural pest in the western United States. In a recent study, proteins from Pantoea ananatis and Serratia marcescens (Enterobacteriales: Enterobacteriaceae) were identified in diet that was stylet probed and fed on by L. hesperus adults. P. ananatis and S. marcescens are ubiquitous bacteria that infect a wide range of crops. The objective of our study was to determine whether L. hesperus transfer P. ananatis and S. marcescens to food substrates during stylet-probing activities. Sucrose (5%) was spread under parafilm and exposed to adult L. hesperus for 24 h. Diet similarly prepared but not exposed to insects was used for controls. MacConkey agar was inoculated with stylet-probed or control diets and incubated at 25°C. After 24 h, bacterial colonies were observed on agar that was inoculated with stylet-probed diet, but were not observed on agar inoculated with control diet. Isolated bacterial colonies were putatively identified as either Pantoea spp. or S. marcescens using the API 20e identification kit. These results indicate that L. hesperus is capable of vectoring P. ananatis and S. marcescens.

The glassy-winged sharpshooter, Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae), is a xylem fluid-ingesting leafhopper that transmits χylella fastidiosa Wells et al., a plant-infecting bacterium that causes several plant diseases in the Americas. Although the role of plant water stress on the population density and dispersal of H. vitripennis has been studied, nothing isknown about the effects of plant water stress on the transmission of χ. fastidiosa by H. vitripennis.Alaboratory study was conducted to determine the influence of plant water stress on the sharpshooter stylet probing behaviors associated with the acquisition and inoculation of χ. fastidiosa. Electrical penetration graph was used to monitor H. vitripennis feeding behaviors for 20-h periods on citrus [Citrus sinensis (L.) Osbeck] and almond [Prunus dulcis (Miller) D.A. Webb] plants subjected to levels of water stress. Adult H. vitripennis successfully located xylem vessels, then performed behaviors related to the evaluation of the xylem cell and fluid, and finally ingested xylem fluid from citrus and almond plants under the tested fluid tensions ranging from -5.5 to -33.0 bars and -6.0 to -24.5 bars, respectively. In general, long and frequent feeding events associated with the acquisition and inoculation of χ. fastidiosa were observed only in fully irrigated plants (i.e., >-10 bars), which suggests that even low levels of plant water stress may reduce the spread of χ. fastidiosa. Results provided insights to disease epidemiology and support the hypothesis that application of regulated deficit irrigation has the potential to reduce the incidence of diseases caused by χ. fastidiosa by reducing the number of vectors and by decreasing pathogen transmission efficiency.

Thrips-transmitted Iris yellow spot virus (IYSV) is an important economic constraint to the production of bulb and seed onion crops in the United States and many other parts of the world. Because the virus is exclusively spread by thrips, the ability to rapidly detect the virus in thrips vectors would facilitate studies on the role of thrips in virus epidemiology, and thus formulation of better vector management strategies. Using a polyclonal antiserum produced against the recombinant, Escherichia coli-expressed nonstructural protein coded by the small (S) RNA of IYSV, an enzyme linked immunosorbent assay was developed for detecting IYSV in individual as well as groups of adult thrips. The approach enabled estimating the proportion of potential thrips transmitters in a large number of field-collected thrips collected from field-grown onion plants. Availability of a practical and inexpensive test to identify viruliferous thrips would be useful in epidemiological studies to better understand the role of thrips vectors in outbreaks of this economically important virus of onion.

In Chile, phytoplasmas have been reported in sugar beet, grapevine, peony, and Chilean shrubs. ‘Candidatus Phytoplasma ulmi' have been detected in plants of Ugni molinae Turczanínow (Myrta- ceae) and the leafhopper Amplicephalus curtulus Linnavuori & DeLong. We evaluated the possibility of phytoplasma transmission from native plants to grasses by A. curtulus and the possible effect on the plant hosts. Newly emerged adults were placed in cages with phytoplasma-infected U. molinae for 72 h (acquisition access period). These plants were then replaced by healthy ryegrasses for 20 d (latent period). They were again replaced for other healthy ryegrasses and were place in cages for 14,7, and 1 d (inoculation access period [IAP]). After IAP, these plants were moved into different insect-free cages for 30 d, after which polymerase chain reaction (PCR) analyses were carried out. Phytoplasma-free insects on ryegrasses were considered as control treatments. Furthermore, plant height and leaf area were recorded for all treatments. After PCR, 46, 60, and 13% of the plants exposed to infected A. curtulus by 14, 7, and 1dof IAP, respectively, were infected with ‘Ca. Phytoplasma ulmi'. Similarly, plants exposed to an IAP of 14, 7, and 1 d with phytoplasma-infected leafhoppers showed a reduction in plant height of 19, 39, and 28% and leaf area of 302, 169, and 55%, respectively, in comparison to those exposed to phytoplasma-free leafhoppers. We showed that A. curtulus has the ability to transmit phytoplasma from U. molinae to ryegrasses, affecting ryegrass plant height and leaf area.

The impact of southern rice black-streaked dwarf virus (SRBSDV) on the life cycle of the vector Sogatella furcifera (Horváth) (Hemiptera: Delphacidae) was investigated. The adult longevity was significantly shorter when the insect was reared on the SRBSDV-infected rice plants than those reared on the noninfected rice treatment. The fecundity of S. furcifera reared on the SRBSDV-infected rice plants was slightly higher than that of those reared on the noninfected rice plants both in macropterous and brachypterous cohorts. In addition, SRBSDV infection in rice increased the population size of macropterous adults from both macropterous and brachypterous cohorts. After a 10 or 15 d feeding period on the SRBSDV-infected rice plants, the amount of honeydew excreted by the insect increased significantly when compared with those reared on the noninfected plants. These results revealed SRBSDV infection improves host suitability for its vector, S. furcifera.

In Liaoning Province, China, tomato yellow leaf curl virus (TYLCV) was first detected in 2009 and in only four counties. To quantify the spread of TYLCV and to identify potential factors influencing its spread in Liaoning Province, we assayed for TYLCV within 1,055 whiteflies (Bemisia tabaci (Gennadius) complex) from 74 populations and 29 counties in 2011. The B. tabaci species of these individuals was determined based on molecular markers. TYLCV was found in 13 counties (Donggang, Liaoyang, Kazuo, Lingyuan, Heishan, Liaozhong, Kaiyuan, Taian, Dawa, Dashiqiao, Beizhen, Linghai, and Xingcheng) and was most frequently detected in the central plain. In addition, the percentage of whiteflies with TYLCV was significantly higher in B. tabaci Q than in B. tabaci B but was unrelated to the hosts (pepper, eggplant, tomato, cucumber, and kidney bean) on which the whiteflies had been collected. These results demonstrate that TYLCV has spread rapidly in Liaoning Province since its first detection and suggest that its spread is more closely associated with the introduction of B. tabaci Q than with the species of host plant. These findings also indicate that controls are now needed to reduce the further spread of TYLCV and that these controls should include the management of B. tabaci Q populations.

In southern South America, Atta vollenweideri Forel (Hymenoptera: Formicidae) is a significant pest of several crops and forestry, also considered to reduce the carrying capacity of pastures. The most usual control method used in Latin America is the application of synthetic pesticides, mainly chlorpyrifos and fipronil. However, no studies have assessed the effects of these agrochemicals on natural enemies of ants. We aimed to evaluate the efficiency of these pesticides on leaf-cutter ants' control and to test their effect on phorid fly parasitoids. Chlorpyrifos failed to exert complete control over ant colonies in the field and was gravely detrimental to specific parasitoids, reducing their percentage of parasitism, pupal survivorship, and adult longevity. Fipronil, however, exerted complete control over the treated colonies. Laboratory tests using both pesticides, either on ants from foraging trails or on pupariae, showed that chlorpyrifos and fipronil decreased larval and pupal survivorship, as well as adult longevity of parasitoids, in comparison to controls. In conclusion, these pesticides will likely affect parasitoids with regard to their reproductive capacity, leading to the decreased levels of natural parasitism observed in the field after treatments. We discuss why neither pesticide should be taken into account for integrated pest management programs.

The potential impacts on natural enemies of crops that produce insecticidal Cry proteins from Bacillus thuringiensis (Bt) are an important part of an environmental risk assessment. Entomopathogenic nematodes are important natural enemies of lepidopteran pests, and the effects of Bt crops on these nontarget organisms should be investigated to avoid disruption of their biological control function. The objective of this study was to investigate the effects of Cry1Ac-expressing transgenic Bt broccoli on the entomopathogenic nematode, Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae), under tri-trophic conditions. Using Cry1Ac-resistant Plutella xylostella L. (Lepidoptera: Plutellidae) larvae as hosts, we evaluated the potential impact of Cry1Acexpressing Bt broccoli on several fitness parameters of H. bacteriophora. Virulence, reproductive potential, time of emergence, and preference of H. bacteriophora for the host (P. xylostella) were not significantly affected when Cry1Ac-resistant P. xylostella larvae were reared on leaves of Cry1Ac or non-Bt broccoli. Also the aforementioned parameters of the subsequent generation of H. bacteriophora did not differ between nematodes obtained from P. xylostella reared on Cry1Ac broccoli compared with those obtained from P. xylostella reared on non-Bt broccoli. To the best of our knowledge, the current study provides the first clear evidence that Cry1Ac does not affect important fitness parameters of H. bacteriophora.

The tomato borer Tuta absoluta Meyrick is a serious tomato pest that has lately undergone a rapid expansion, causing severe crop losses. An integrated management is required to control this insect, within which biological control is now beginning to play a key role. In this regard, the effectiveness of a liquid formulation based on strains of the fungus Metarhizium anisopliae variety anisopliae (Metschnikoff) Sorokin (4.46 × 10 viable conidia per milliliter), applied together with irrigation water, has been evaluated by laboratory tests on different populations of T. absoluta. A bioassay method has been developed to test the efficacy of the product. The technique chosen has been validated and the different studied populations have been typified according to their susceptibility, determining the baseline susceptibility of the pest to the fungus. The results revealed a complete efficacy of M. anisopliae against pupae of T. absoluta at the recommended label rate (5.58 × 10⁹ viable conidia per liter) for the populations assayed. Moreover, a notably lower dose was also sufficiently effective to control the tomato borer populations because values of LC₉₀ lower than 3 × 10⁹ viable conidia per liter were obtained unfailingly. The most sensitive populations were those collected in Almeria and Nijar, Spain, with LC₅₀ values of 0.21 and 0.22 × 10⁹ viable conidia per liter^-1, respectively. The average value obtained for LC₅₀ was 0.34 × 10 viable conidia per liter^-1 and 2 × 10 for LC₉₀. These results show the potential of M. anisopliae to control pupae of the tomato borer in integrated pest management programs.

Tests evaluating the host range of Tamarixia radiata (Waterson) (Hymenoptera: Eulophidae), a parasitoid of the pestiferous Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), sourced from the Punjab of Pakistan, were conducted in quarantine at the University of California, Riverside, CA. Seven nontarget psyllid species (five native and two self-introduced species) representing five families were exposed to T. radiata under the following three different exposure scenarios: 1) sequential no-choice tests, 2) static no-choice tests, and 3) choice tests. Nontarget species were selected for testing based on the following criteria: 1) taxonomic relatedness to the target, D. citri; 2) native psyllids inhabiting native host plants related to citrus that could release volatiles attractive to T. radiata; 3) native psyllids with a high probability of occurrence in native vegetation surrounding commercial citrus groves that could be encountered by T. radiata emigrating from D. citr-infested citrus orchards; 4) a common native pest psyllid species; and 5) a beneficial psyllid attacking a noxious weed. The results of host range testing were unambiguous; T. radiata exhibited a narrow host range and high host specificity, with just one species of nontarget psyllid, the abundant native pest Bactericera cockerelli Sulc, being parasitized at low levels (<5%). These results suggest that the likelihood of significant nontarget impacts is low, and the establishment of T. radiata in southern California for the classical biological control of D. citri poses negligible environmental risk.

The aim of this study was to explore a cost-effective method for the mass production of Bacillus thuringiensis (Bt) by solid-state fermentation. As a locally available agroindustrial byproduct, spent mushroom substrate (SMS) was used as raw material for Bt cultivation, and four combinations of SMS-based media were designed. Fermentation conditions were optimized on the best medium and the optimal conditions were determined as follows: temperature 32°C, initial pH value 6, moisture content 50%, the ratio of sieved material to initial material 1:3, and inoculum volume 0.5 ml. Large scale production of B. thuringiensis subsp. israelensis (Bti) LLP29 was conducted on the optimal medium at optimal conditions. High toxicity (1,487 international toxic units/milligram) and long larvicidal persistence of the product were observed in the study, which illustrated that SMS-based solid-state fermentation medium was efficient and economical for large scale industrial production of Bt-based biopesticides. The cost of production of 1 kg of Bt was approximately US$0.075.

The combination of essential oils and Bacillus thuringiensis Berliner may represent an interesting control strategy. Thus, the study tested the following hypothesis: the combination of long pepper oil (Piper hispidinervum L.) and clove (Syzygium aromaticum L.) oils in two concentrations with Xentari WG (Bta) yields a more effective control of Spodoptera frugiperda (JE Smith) (Lepidoptera: Noctuidae) affecting biological and reproductive parameters and leading to changes in the levels of phenoloxidase and nitric oxide in the hemolymph of the pest. The results demonstrate that only long pepper oil, at the highest concentration with Xentari WG (Bta), promotes reduced larval survival. However, both oils with or without the insecticide interfere in the biology and humoral immunity of S. frugiperda. All treatments caused a decrease in the amount of eggs, except for the clove oil at both concentrations without Bta. Therefore, the use of these oils is a promising alternative for the integrated management of S. frugiperda; however, its association with Bta demonstrated no significant increase in their efficiency.

Phlyctinus callosus (Boheman) (Coleoptera: Curculionidae) is a pest of major phytosanitary concern for some of South Africa's biggest export markets such as the United States and Europe because this pest does not occur there. At present, fumigation with methyl bromide is the only postharvest disinfestation treatment against this pest; therefore, sustainable alternatives are needed. One such alternative is irradiation treatment of whole pallets of packed fruit to sterilize insects that may be present within the cartons. Wild adult P. callosus weevils were treated with 5, 10, 20, 40, and 80 Gy of γ-irradiation and then cross mated to breed with either treated or nontreated adults of the opposite sex. Fecundity and fertility were monitored and recorded. Trials were conducted during the 2009–2010 and 2010–2011 fruit harvesting seasons. The results from both seasons indicated that irradiation did not affect fecundity but fertility was significantly affected, decreasing as irradiation doses increased. Egg hatch was zero for mating crosses that involved females weevils treated with a dose of 80 Gy γ-irradiation. Probit analysis indicated that in the first season, the estimated LD₉₅ for crosses involving treated males and treated females was 30 Gy, while in the second season it was 49.5 Gy. Respective estimated LD₉₉s were 47.9 and 169.4 Gy. Ultimately, a dose lower than the current generic dose of 400 Gy, approved for irradiation disinfestation treatments, would control P. callosus should they occur in packed export fruit.

The mango pulp weevil, Sternochetus frigidus (F.), is an important quarantine pest preventing the export of mangoes from the Philippines to the United States and other countries. Previously, a radiation dose of 100 Gy was proposed for phytosanitary treatment of S. frigidus based on dose-response studies with larvae, pupae, and adult weevils. To validate an irradiation treatment, large-scale confirmatory tests were conducted with adults (the most radiation-tolerant stage) in mangoes at 100 and 150 Gy. After treatment, adults were removed from fruit, sexed, and mated in pairs to observe any reproduction. At 100 Gy, adults laid a small number of eggs but none of the eggs hatched. At 150 Gy (measured doses 96.7–164.1 Gy), 4,559 treated weevils laid no eggs, indicating that this dose caused complete sterility. Irradiation treatment with a minimum absorbed dose of 165 Gy will therefore provide quarantine security for S. frigidus in exported Philippine mangoes.

Life history parameters were established under controlled laboratory conditions for the green stink bug, Chinavia hilaris (Say) (= Acrosternum hilare), to improve pest control in pistachios in California. Parameters measured and calculated included survival and development at seven constant temperatures (ranging from 15 to 35°C), development time, upper and lower development thresholds, thermal constants, fecundity, generation time, net reproductive rate, and intrinsic rate of increase. C. hilaris did not complete development at 15 and 35°C. Within the range of 20–27.5°C, development time decreased linearly with temperature; it increased again at 30°C. The lower threshold was calculated by linear methods to be 12.3°C, and the thermal constant was calculated to be 588 degree days. Fastest development was recorded at 27.5°C, whereas greatest survival was observed at 22.5°C. At 27.5°C, mean fecundity was 53.5 eggs per female, mean generation time was 74.4 d, net reproductive rate was 20.09, and intrinsic rate of increase was 0.04. Use of a nonlinear model yielded estimates of 13.2, 28.4, and 33.4°C, for the lower threshold, optimum temperature, and upper threshold, respectively. Results were compared with similar studies and interpreted in the light of pest management needs in pistachio. Increased emphasis on monitoring and management of overwintering sites and early-season migration are recommended.

Thousand cankers disease, caused by the walnut twig beetle (Pityophthorus juglandis Blackman) and an associated fungal pathogen (Geosmithia morbida M. Kolarík, E. Freeland, C. Utley, and N. Tisserat), threatens the health and commercial use of eastern black walnut (Juglans nigra L.), one of the most economically valuable tree species in the United States. Effective phytosanitary measures are needed to reduce the possibility of spreading this insect and pathogen through wood movement. This study evaluated the efficacy of heat treatments and debarking to eliminate P. juglandis and G. morbida in J. nigra logs 4–18 cm in diameter and 30 cm in length. Infested logs were steam heated until various outer sapwood temperatures (60, 65, and 70°C in 2011; 36, 42, 48, 52, and 56°C in 2012) were maintained or exceeded for 30–40 min. In 2011, all heat treatments eliminated G. morbida from the bark, but logs were insufficiently colonized by P. juglandis to draw conclusions about treatment effects on the beetle. Debarking did not ensure elimination of the pathogen from the sapwood surface. In 2012, there was a negative effect of increasing temperature on P. juglandis emergence and G. morbida recovery. G. morbida did not survive in logs exposed to treatments in which minimum temperatures were 48°C or higher, and mean P. juglandis emergence decreased steadily to zero as treatment minimum temperature increased from 36 to 52°C. A minimum outer sapwood temperature of 56°C maintained for 40 min is effective for eliminating the thousand cankers disease vector and pathogen from walnut logs, and the current heat treatment schedule for the emerald ash borer (60°C core temperature for 60 min) is more than adequate for treating P. juglandis and G. morbida in walnut firewood.

As part of sterile insect technique (SIT) programs, irradiation can effectively induce sterility in insects by damaging genomic DNA. However, irradiation also induces other off-target side effects that reduce the quality and performance of sterilized males. Thus, treatments that reduce off-target effects of irradiation on male performance while maintaining sterility can improve the feasibility and economy of SIT programs. Exposure to ionizing radiation induces the formation of damaging free radicals in biological systems that may reduce sterile male performance. Here, we test whether exposure to an anoxic environment for 1 h before and during irradiation improves male performance, while maintaining sterility in males of the cactus moth, Cactoblastis cactorum (Berg). We show that exposure to 1 h of anoxia increases the moth's antioxidant capacity and that irradiation in anoxia after 1 h of anoxic conditioning decreases irradiation-induced oxidative damage to the moth's lipids and proteins. Anoxia treatment that reduced oxidative damage after irradiation also produced moths with greater flight performance, mating success, and longevity, while maintaining F₁ male sterility at acceptable levels for SIT. We conclude that anoxia pretreatment followed by irradiation in anoxia is an efficient way to improve the quality of irradiated moths and perhaps lower the number of moths needed for release SIT moth operations.

One of the most important factors for the success of a mass trapping strategy to control a fruit fly involves the selection of an effective trap—lure combination. Because different species of fruit flies respond differently to the physical characteristics of a trap and to bait volatiles, the evaluation of commercial traps and lures that have proved useful against other tephtrids is necessary to determine their efficacy for mass trapping of Anastrepha ludens (Loew) (Diptera: Tephritidae). Under caged conditions, a commercial hemispherical trap with lateral holes (Maxitrap Plus) proved more attractive to A. ludens (both sexes) than five other commercial traps that were all baited with hydrolyzed protein. Among these traps, bottom invaginated traps and traps with invaginated lateral holes constructed with transparent cylinders had the best physical retention properties. When evaluated under field conditions, the lure was critical for the efficacy of the trap, and one of the traps that performed poorly in attraction and retention cage tests (MS2) resulted as one of the most effective traps when baited with CeraTrap lure. Considering the use of different trap models under field conditions, CeraTrap liquid bait was more effective in A. ludens capture than Biolure dry synthetic bait, but both lures were not replaced during the entire course of the experiment. The percentage of captured females was also slightly higher using CeraTrap lure (67.2%) than using Biolure baits (54.5–58.8%). In field tests, 75–81% of females were mated and no significant differences were observed among trap—lure combinations. Trap selectivity against nontarget adult lacewings also differed among trap—lure combinations.

A method to improve an assay relating adult feeding to egg maturation by the glassywinged sharpshooter (Hemiptera: Cicadellidae) was evaluated. The assay consisted on confining females to cowpea stems and quantifying feeding and egg maturation. Feeding was quantified by measuring excreta production. The number of eggs matured during the assay was estimated by taking the difference between female egg load (number of mature eggs carried by a female) at end of the assay (determined by dissection) and mean egg load of a subset of females dissected at start of the assay. Estimates of the number of mature eggs produced by females using the aforementioned approach improve as variability in egg loads of females entering the assay declines. As egg loads of females are variable, a pretreatment designed to reduce variance in egg loads of females entering the assay was evaluated. To accomplish this, females were divided into two groups. The control group was placed directly into the assay. The pretreatment group was given an oviposition period on sorghum before the assay. An oviposition period on sorghum was expected to reduce variance in egg load among females, as previous research found that sorghum was suitable for oviposition but provided poor nutrition for egg maturation. Dissection of a subset of females from each group before the assay determined that the mean and variance in egg load of females receiving the pretreatment was significantly reduced compared with females in the control group. Analysis of results from the feeding assay found that there was a significant relationship between feeding and egg maturation for females receiving the pretreatment, but not for females in the control group. Thus, reducing the mean and variance in egg load of females entering feeding assays resulted in detection of a significant positive relationship between feeding and egg maturation that otherwise would not have been observed.

Linepithema micans (Forel) (Hymenoptera: Formicidae) is the main ant species responsible for the spreading of Eurhizococcus brasiliensis (Wille) (Hemiptera: Margarodidae), a soil scale that damages grapevine plants in southern Brazil. The effect of contact and ingestion of insecticides on the control of L. micans was evaluated in a greenhouse using grapevines (Vitis spp.) infested by L. micans. The insecticides thiamethoxam (250, 187.5, and 125 g/ha), fipronil (4, 5, and 50 ml/ha), and imidacloprid (650 g/ha) were sprayed on the ground, whereas toxic baits containing boric acid (0.5, 1.0, and 1.2%), pyriproxyfen (0.3 and 0.5%), and hydramethylnon (0.5%) were evaluated in different formulations. Hydramethylnon (toxic bait) and thiamethoxam (chemical barrier) were the most efficient active ingredients for the control of L. micans.

Nowadays, heavy metal pollution has become more and more serious. Cadmium is one of the heavy metals that have caused serious pollution. Spodoptera exigua Hübner (Lepidoptera: Noctuidae), one of important agricultural pests, has broken out more frequently in recent years. In this study, accumulation at different developmental stages and excretion of Cd were detected, and effect of cadmium (Cd concentrations were 0.2, 0.8, 3.2, 12.8, and 51.2 mg/kg, respectively) on three successive generations of beet armyworm was also studied using life table in the laboratory. Results showed that Cd² contents were significantly different when S. exigua was reared under different Cd² concentrations in the same generation in a significant dosedependent manner. The concentration of Cd² increased with extension of stress time. Cd² concentration at different developmental stages was different, that is, larvae > pupa > adult. After emergence, Cd² concentration in both females and males decreased gradually, but that in paired adults decreased to a greater extent than that in unpaired ones. Beet armyworm could excrete heavy metals by means of faeces, prepupa exuviate, and puparium. Life table of the laboratory population was constructed, which showed that low doses of cadmium promoted the increase of population, whereas high doses inhibited the increase, meanwhile, with the extension of exposure length, the index of population trend (I) declined more rapidly. The study might provide references for the long-term and objective assessment of heavy metal pollution and its effect on the populations of important agricultural pests.

Western corn rootworm (Diabrotica virgifera virgifera LeConte) larvae use carbon dioxide (CO₂) to locate the roots of their hosts. This study investigated whether an encapsulated CO₂ source (CO₂-emitting capsules) is able to outcompete CO₂ gradients established by corn root respiration in the soil. Furthermore, the following two management options with the capsules were tested in semifield experiments (0.5- to 1-m² greenhouse plots): the disruption of host location and an “attract-and-kill” strategy in which larvae were lured to a soil insecticide (Tefluthrin) between the corn rows. The attract-and-kill strategy was compared with an application of Tefluthrin in the corn rows (conventional treatment) at 33 and 18% of the standard field application rate. Application of the CO₂-emitting capsules 30 cm from the plant base increased CO₂ levels near the application point for up to 20 d with a peak at day 10. Both the disruption of host location and an attract-and-kill strategy caused a slight but nonsignificant reduction in larval densities. The disruption of host location caused a 17% reduction in larval densities, whereas an attract-and-kill strategy with Tefluthrin added at 33 and 18% of the standard application rate caused a 24 and 27% reduction in larval densities, respectively. As presently formulated, the CO₂-emitting capsules, either with or without insecticide, do not provide adequate control of western corn rootworm.

Scouting at key times in the seasonal development of insect pest populations, as guided by degree-day accumulation, is important for minimizing unwarranted insecticide application. Fields of small grains in northern Utah were censused weekly from 2001 to 2011, to assess infestation by the cereal leaf beetle, Oulema melanopus (L.) (Coleoptera: Chrysomelidae), and develop degree-day guidelines for measuring cereal leaf beetle abundance at peak egg and larval densities in any given year. Even in years of high overall numbers of cereal leaf beetle, relatively few fields were heavily infested (with 20 or more cereal leaf beetle eggs larvae per 0.09 m²) at either egg or larval peak density during the growing season. In individual fields, the number of immature cereal leaf beetle (eggs larvae) at peak larval density was positively related to the number of immature cereal leaf beetles present earlier at peak egg density. Although there was large variation among years in when cereal leaf beetle egg and larval numbers peaked during the season as measured by degree-day accumulation from 1 January, much of this variation was accounted for by the warmth of the early spring before significant egg laying occurred. Hence, degree-day estimates that account for early spring warmth can guide growers in scouting grain fields at peak egg densities to identify fields at high risk of subsequent economic damage from cereal leaf beetle larval feeding. The relatively low incidence of fields heavily infested by cereal leaf beetle in northern Utah emphasizes the benefit that growers can gain by scouting early before applying insecticide treatments.

Eastern hemlocks (Tsuga canadensis Carrière) at two sites in southwestern Virginia were treated by trunk and soil injections of imidacloprid to determine the insecticide's impact on hemlock woolly adelgid, Adelges tsugae Annand. Treatments were 25, 50, and 100% of the highest labeled dosage rates for both stem and soil injection. Three and 4 yr after treatment, the half and full rates had significantly reduced A. tsugae populations, which were accompanied by increased new hemlock shoot growth and higher hemlock health scores on a visual rating of tree appearance. Imidacloprid and metabolite concentrations in tissue of treated trees were determined by liquid chromatography—tandem mass spectrometry, and A. tsugae density decreased as imidacloprid concentrations increased in wood tissue. There were no observed A. tsugae populations in all trees with imidacloprid tissue concentrations >413 ppb. Olefin, di-hydroxy, and 6-chloro-nicotinic-acid metabolites were the imidacloprid metabolites recovered in the highest concentrations. This suggests that hemlock metabolism of imidacloprid may increase efficacy of the parent compound. Stem and soil treatments of low rates of systemic imidacloprid reduce adelgid populations and promote hemlock health, but still may provide a remnant food source for beneficial predators.

The attraction of cerambycid beetles to 10 known cerambycid pheromones was tested in a tropical montane rain forest in southern China. From 28 May to 25 June 2010, 1,526 cerambycids representing 71 species were captured in pheromone-baited traps, with 14 species accounting for 92% of the specimens. Test compounds with a 3-hydroxyalkan-2-one or 2,3-alkanediol motif attracted significant numbers of both sexes for eight species in the subfamily Cerambycinae, including species of Demonax, Rhaphuma, and χylotrechus. Rhaphuma horsfieldi (White) was the only species that was strongly attracted to more than one test compound, with significant attraction to both (2R*,3R*)-2,3-hexanediol and (2R*,3R*)-2,3-octanediol. Within the Lamiinae, males and females of five species were significantly attracted to 2-(undecyloxy)ethanol, including Acalolepta formosana (Breuning), Monochamus bimaculatus Gahan, Pharsalia subgemmata (Thomson), Pseudomacrochenus antennatus (Gahan), and χenohammus bimaculatus Schwarzer. Only male Megopis costipennis White (Prioninae) were significantly attracted to (2R*,3S*)-2,3-octanediol, suggesting that this compound may be a sex pheromone component for this species. To date, 2,3-octanediols have only been reported as aggregation pheromone components for cerambycids in the subfamily Cerambycinae. Our results support the hypothesis that both closely related (congeners) and more distantly related cerambycid species (different tribes and even subfamilies) may share pheromone components. Our results also demonstrate that traps baited with even a limited number of different classes of pheromones may be useful tools for surveying cerambycid diversity, as well as for detecting and monitoring particular species, especially those that have the potential to be invasive pests in other parts of the world.

Poplars are frequently attacked by aphids. The differential susceptibility of poplar hybrids to the aphid Chaitophorus leucomelas Koch (Sternorrhyncha: Aphididae) has been described, but the mechanism underlying this pattern is unknown. This work tested the hypothesis that poplar resistance to this aphid is associated with the presence of volatiles and secondary plant compounds that affect host selection and feeding behavior. This hypothesis was tested by studying the host choice and feeding be havior of C. leucomelas on two poplar hybrids with contrasting susceptibilities to this aphid ([Populus trichocarpa Torrey & Gray × Populus deltoides Bartram ex Marshall] × P. deltoides [TD × D] , and [P. trichocarpa × Populus maximowiczii Henry] × [P. trichocarpa × P. maximowiczii] [TM × TM]). The results showed that C. leucomelas rejected leaves of the TM × TM hybrid and did not prefer odors from either hybrid. Electronic monitoring of the probing behavior of C. leucomelas suggested the involvement of antifeedant factors in the TM × TM hybrid. In addition, the chemical characterization of volatiles, epicuticular waxes, and internal phenols of leaves from both poplar hybrids revealed that TM × TM had a higher abundance of monoterpenes, sesquiterpenes, n-alkanes, and phenols. These results are discussed in terms of their contribution to poplar breeding programs aimed at enhancing insect resistance.

A series of bioassays were conducted to determine the relative toxicities and residual activities of insecticides labeled for use in blueberry (Vaccinium corymbosum L.) on natural enemies, to identify products with low toxicity or short duration effects on biological control agents. In total, 14 insecticides were evaluated using treated petri dishes and four commercially available natural enemies (Aphidius colemani Viereck, Orius insidiosus [Say], Chrysoperla rufilabris [Burmeister], and Hippodamia convergens [Guérin-Menéville]). Dishes were aged under greenhouse conditions for 0, 3, 7, or 14 d before introducing insects to test residual activity. Acute effects (combined mortality and knockdown) varied by insecticide, residue age, and natural enemy species. Broad-spectrum insecticides caused high mortality to all biocontrol agents, whereas products approved for use in organic agriculture had little effect. The reduced-risk insecticide acetamiprid consistently caused significant acute effects, even after aging for 14 d. Methoxyfenozide, novaluron, and chlorantraniliprole, which also are classified as reduced-risk insecticides, had low toxicity, and along with the organic products could be compatible with biological control. This study provides information to guide blueberry growers in their selection of insecticides. Further research will be needed to determine whether adoption of a pest management program based on the use of more selective insecticides will result in higher levels of biological control in blueberry.

An assessment was made of the fumigant toxicity of 36 constituents from lemon balm oil (LBO) and summer savory oil (SSO) and another additional nine previously identified compounds of the oils, as well as of the control efficacy of four experimental spray formulations containing individual oils (0.5 and 0.1% sprays) and spinosad 10% suspension concentrate (SC) to females from B- and neonicotinoid-resistant Q-biotypes of Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae). Based on 24-h LC₅₀ values, Q-biotype females (0.20 µg/cm³) were 40 times less susceptible to dichlorvos than B-biotype females (0.005 µg/cm³). Thymol (LC₅₀, 0.35 µg/cm³) and carvacrol (0.56 µg/cm³) were the most toxic compounds toward Q-biotype females, followed by (1S)-( — )-borneol, α-terpineol, nerol, linalool, and carvone (1.06–1.38 µg/cm³). The toxicity of these compounds was virtually identical toward both biotype females, indicating that the terpenoids and the insecticides (neonicotinoids and dichlorvos) do not share a common mode of action or elicit cross-resistance. The 0.5% spray of LBO, SSO, and spinosad 10% SC resulted in >90% mortality toward both biotype females. Global efforts to reduce the level of toxic synthetic insecticides in the agricultural environment justify further studies on LBO- and SSO-derived materials as potential contact-action fumigants for the control of B. tabaci populations.

Hand removal is often recommended as a method for small-scale control of Japanese beetles (Popillia japonica Newman). In this study, we investigated the effectiveness of daily hand removal for controlling damage by Japanese beetles on grape plants. We also investigated whether the timing of the removal (at 0800, 1400, or 1900 hours, or at all 3 periods) influenced the effectiveness of the technique. We found that hand removal significantly lowered the number of beetles on, and consequently the damage to, grape plants relative to nonremoval controls. Of the single removal treatments, removal of beetles at 1900 hours was most effective, with results similar to removing beetles three times per day. The majority of beetles removed from plants during the experiment were female, a pattern that matches our understanding of aggregation formation behavior in the species, and which may serve to enhance the benefits of hand removal. Hand removal seems to work by decreasing the number of feeding beetles, which in turn reduces the release of aggregation kairomones from the plant, and subsequently decreases the attractiveness of the plant to future beetles.

Catches of Bactrocera invadens Drew, Tsuruta, & White (Diptera: Tephritidae) in Multi-lure traps baited with six commercial food-based attractants, Mazoferm E802, Torula yeast, GF-120, Hymlure, Biolure, and Nulure were compared in mango orchards in Kenya. In 2007, Mazoferm E802 and Torula yeast were the most effective attractants and captured 2.4-2.6 times more females and 3.4-4.0 times more males than the standard Nulure. All attractants captured more females than males (ranging from 63 to 74%). In 2008, Mazoferm E802 was the most effective bait capturing 5.6 and 9.1 times more females and males, respectively, than the standard Nulure. Among all the attractants, in both years, Nulure captured the greatest proportion of females: 74% compared with 51–68% for the other attractants. In 2008, the use of Mazoferm E802 in combination with spinosad as a bait spray in mango orchards reduced B. invadens catches relative to the control by 87% within 4 wk and 90% within 8 wk. At harvest, the proportion of fruit infested was significantly lower in the treated orchards (8%) compared with the control orchards (59%). Estimated mango yield was significantly higher in orchards receiving the bait sprays (12,487 kg/ha) compared with control orchards (3,606 kg/ha). Based on bait spray costs, yield data, and monetary gains, a cost—benefit ratio of 1:9.1 was realized, which is acceptable for growers. In 2009, the experiment was repeated with similar results. We have demonstrated that Mazoferm E802, used alone for monitoring of B. invadens or in conjunction with spinosad for population suppression, shows great promise in Kenya.

Blueberry gall midge, Dasineura oxycoccana (Johnson), is a pest of cultivated blueberries throughout the world. Larvae feed and develop in developing leaf buds, and also in flower buds of rabbiteye blueberries, which causes buds to fall off the plant. These injuries can cause up to 80% yield loss in heavy infestations. As the larvae are protected from insecticides, adults must be targeted with foliar applications. Consequently, the detection of adults through an effective monitoring program is critical to time insecticide sprays against the blueberry gall midge. Understanding the distribution of the midge and its parasitoids is also important information for developing a more effective pest management program. A comparison of three monitoring trap types demonstrated that bucket emergence traps and clear panel traps captured similar numbers of midges, although the bucket trap is more sensitive at low population levels. Using bucket emergence traps, we found that nearly 80% of the midges collected pupated within 48 cm of the blueberry bush, suggesting that a targeted soil treatment may be a viable integrated pest management tactic that could be included in a midge management program. Traps and bud samples demonstrated that adult and larval midges and parasitoids were randomly distributed throughout the field in both years, with the exception of larval aggregation in early 2012. As parasitoid distribution is parallel to host occurrence within blueberry plantings, this increases the potential for biological control activities against the blueberry gall midge in fields that do not receive broad-spectrum insecticide applications.

Outdoor residual sprays are among the most common methods for targeting pestiferous ants in urban pest management programs. If impervious surfaces such as concrete are treated with these insecticides, the active ingredients can be washed from the surface by rain or irrigation. As a result, residual sprays with fipronil and pyrethroids are found in urban waterways and aquatic sediments. Given the amount of insecticides applied to urban settings for ant control and their possible impact on urban waterways, the development of alternative strategies is critical to decrease the overall amounts of insecticides applied, while still achieving effective control of target ant species. Herein we report a “pheromone-assisted technique” as an economically viable approach to maximize the efficacy of conventional sprays targeting the Argentine ant. By applying insecticide sprays supplemented with an attractive pheromone compound, (Z)-9-hexadecenal, Argentine ants were diverted from nearby trails and nest entrances and subsequently exposed to insecticide residues. Laboratory experiments with fipronil and bifenthrin sprays indicated that the overall kill of the insecticides on Argentine ant colonies was significantly improved (57–142% increase) by incorporating (Z)-9-hexadecenal in the insecticide sprays. This technique, once it is successfully implemented in practical pest management programs, has the potential of providing maximum control efficacy with reduced amount of insecticides applied in the environment.

Toxicity, repellency, and performance of three insecticides, β-cyfluthrin EC, fipronil granules, and an essential oil EC formulation, were evaluated against the Asian cockroach, Blattella asahinai Mizukubo, in field and laboratory experiments. The β-cyfluthrin EC and fipronil granules were significantly more toxic than the essential oil EC formulation under continuous exposure conditions, with LT₅₀ values of 0.014, 0.45, and 11.45 d, respectively. The β-cyfluthrin EC and fipronil granules were also significantly more toxic than the essential oil EC formulation in an Ebeling choice box test with LT₅₀ values of 0.64, 1.98, and 59.64 d, respectively. Field applications of insecticides at label rates to Asian cockroach populations in Dothan, AL, showed that β-cyfluthrin EC and fipronil granules reduced populations by 100% at 7 and 30 d after treatment. The essential oil EC formulation initially reduced populations by 68% at 7 d, but control diminished to 2% by 30 d. Results of the field applications and laboratory experiments demonstrate that the β-cyfluthrin EC and fipronil granules provide excellent control of Asian cockroach populations.

Application of insecticides is the most important method to control Chilo suppressalis (Walker) (Lepidoptera: Crambidae), and continuous use of individual insecticides has driven the rapid development of insecticide resistance in C. suppressalis during the past 30 yr. Monitoring insecticide resistance provides information essential for integrated pest management. Insecticide resistance of field populations to monosultap, triazophos, chlorpyrifos, and abamectin in China was examined in 2010 and 2011. The results indicated that the resistance levels of 14 field populations to four insecticides were significantly different. Four populations showed moderate resistance, and other populations possessed low-level resistance or were susceptible to monosultap. Nine populations displayed an extremely high or a high level of resistance to triazophos, whereas four populations were sensitive to this agent. Five populations exhibited a low level of resistance to abamectin, while the others remained sensitive. When compared with historical data, resistance to monosultap and triazophos decreased significantly, and the percentage of populations with high-level or extremely high-level resistance was obviously reduced. By contrast, the resistance to abamectin increased slightly. The increasing and decreasing resistance levels reported in this study highlight the different evolutionary patterns of insecticide resistance in C. suppressalis. An overreliance on one or two insecticides may promote rapid development of resistance. Slow development of resistance to abamectin, which was used mainly in mixtures with other insecticides, implies that the use of insecticide mixtures may be an effective method to delay the evolution of resistance to insecticides.

Increasing adoption of transgenic crops expressing cry toxin genes from Bacillus thuringiensis (Bt crops) represents an augmented risk for development of insect resistance. While fitness costs can greatly influence the rate of resistance evolution, most available data related to Bt resistance have been obtained from laboratory-selected insect strains. In this article, we test the existence of fitness costs associated with high levels of field-evolved resistance to Bt maize event TC1507 in a strain of Spodoptera frugiperda (JE Smith) originated from maize fields in Puerto Rico. Fitness costs in resistant S. frugiperda were evaluated by comparing biological performance to susceptible insects when reared on meridic diet, maize or soybean leaf tissue, or cotton reproductive tissues. Parameters monitored included larval survival, larval and pupal weights, developmental time (larval and pupal), adult longevity, reproductive traits (fecundity and fertility), and sex ratio. We found that all monitored parameters were influenced to a similar extent by the host, independently of susceptibility to Bt maize. The only parameter that significantly differed between strains for all hosts was a longer larval developmental period in resistant S. frugiperda, which resulted in emergence asynchrony between susceptible and resistant adults. To test the relevance of fitness costs in resistant S. frugiperda, we performed a selection experiment to monitor the stability of resistance in a heterogeneous strain through 12 generations of rearing on meridic diet. Our data demonstrate lack of fitness costs relevant to stability of field-evolved resistance to Bt maize and help explain reported stability of field-evolved resistance in Puerto Rican populations of S. frugiperda.

Fitness costs can delay pest resistance to crops that produce insecticidal toxins derived from the bacterium Bacillus thuringiensis (Bt), and past research has found that entomopathogens impose fitness costs of Bt resistance. In addition, entomopathogens can be used for integrated pest management by providing biological control of pests. The western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), is a major pest of maize and is currently managed by planting of Bt maize. We tested whether entomopathogenic nematodes and fungi increased mortality of western corn rootworm and whether these entomopathogens increased fitness costs of resistance to Cry3Bb1 maize. We exposed western corn rootworm larvae to two species of nematodes, Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae) and Steinernema feltiae Filipjev (Rhabditida: Steinernematidae), and to two species of fungi, Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Cordycipitaceae) (strain GHA) and Metarhizium brunneum (Metschnikoff) Sorokin (Hypocreales: Clavicipitaceae) (strain F52) in two assay types, namely, seedling mat and small cup. Larval mortality increased with the concentration of H. bacteriophora and S. feltiae in the small cup assay, and with the exception of S. feltiae and B. bassiana in the seedling mat assay, mortality from entomopathogens was significantly greater than zero for the remaining entomopathogens in both assays. However, no fitness costs were observed in either assay type for any entomopathogen. Increased mortality of western corn rootworm larvae caused by these entomopathogens supports their potential use in biological control; however, the lack of fitness costs suggests that entomopathogens will not delay the evolution of Bt resistance in western corn rootworm.

Litchi (Litchi chinensis Sonnerat) is native to Southeast Asia, where most of the world cultivation of this crop is done. Its commercial cultivation in Brazil is recent and concentrated in the state of São Paulo. This crop has been severely damaged in Asia and Brazil by the litchi erineum mite, Aceria litchii (Keifer) (Eriophyidae). The objectives of this study were the adaptation of a method to estimate the density of A. litchii, an evaluation of the population dynamics of this pest and of its associated predators in the state of São Paulo, and an estimation of its injury levels to litchi trees. To estimate the density of A. litchii, an adaptation of a method commonly used to evaluate nematode densities in plant roots was performed. This method was shown to be adequate for the estimation of the number of A. litchii, and it might also be useful for similar evaluations of other erineum forming mites. Field samples to determine the pest population dynamics were collected monthly from August 2011 to July 2012. Sampled leaves were examined under a stereomicroscope for removal of predators and subsequent extraction of A. litchii by the adapted method. A. litchii reached maximum densities in November 2011 and June 2012, being found at low densities between January and March 2012. The pattern of variation of A. litchii injury levels was similar to that of the density of A. litchii. The main predatory mite co-occurring with A. litchii was the phytoseiid Phytoseius intermedius Evans and McFarlane. However, high injury levels due to A. litchii suggest that the predator was unable to prevent visible damages to the trees, indicating that control activities should be adopted by growers.

Bacillus thuringiensis (Bt) maize was developed primarily for North American pests such as European corn borer (Ostrinia nubilalis (Hübner)). However, most Bt maize products are also cultivated outside of North America, where the primary pests may be different and may have lower susceptibility to Bt toxins. Fall armyworm (Spodoptera frugiperda JE Smith) is an important pest and primary target of Bt maize in Central and South America. S. frugiperda susceptibility to Cry1F (expressed in event TC1507) is an example of a pest-by-toxin interaction that does not meet the high-dose definition. In this study, the behavioral and toxic response of S. frugiperda to Cry1F maize was investigated by measuring the percentage of time naïve third instars spent feeding during a 3-min exposure. S. frugiperda also were exposed as third instars to Cry1F maize for 14 d to measure weight gain and survival. S. frugiperda demonstrated an initial, postingestive aversive response to Cry1F maize, and few larvae survived the 14 d exposure. The role of susceptibility and avoidance are discussed in the context of global IRM refuge strategy development for Bt products.

We evaluated the susceptibility of 15 mango cultivars to the attack of Anastrepha ludens (Loew) and Anastrepha obliqua (Macquart) (Diptera: Tephritidae), the main tephritid pests of this crop in Mexico. In a field experiment, bagged fruit-bearing branches were exposed to gravid females of both fly species. Infestation rates, developmental time, adult eclosion, and F1 adult longevity, fecundity, and fertility were recorded, ranking cultivars in terms of susceptibility to fly attack and development. We also compared the volatile profile in selected resistant and susceptible cultivars in search of possible correlations. In a second experiment, clutch size for A. ludens was determined in each cultivar. Infestation rates, developmental time, and F1 demographic parameters varied sharply among cultivars and between fly species for bagged fruit. Cultivars ‘Vishi,’ ‘74 – 82,’ and ‘Brooks’ were most susceptible to A. ludens infestation while ‘Tommy,’ ‘Sensation,’ and ‘Ataulfo “niño’” (partheno- carpic fruit) were most susceptible to A. obliqua infestation. ‘Edward,’ ‘Kent,’ ‘Brooks late,’ ‘Palmer,’ and ‘Ataulfo’ exhibited tolerance to attack of both fly species. Fruit of susceptible and resistant cultivars exhibited unique volatile profiles. Fly development and F1 adult demographic parameters varied significantly among cultivars. A. ludens females laid larger clutches in larger and harder fruit. We highlight the important role of Ataulfo “niño” as pest reservoir if fruit is left unharvested on trees. We discuss the possible use of highly resistant cultivars as trap crops or egg sinks.

Heat stress exerts a profound impact on the resistance of plants to parasites. In this research, we investigated the impact of an acute transient heat stress on the resistance of the wheat line ‘Molly,’ which contains the R gene H13, to an avirulent Hessian fly (Mayetiola destructor (Say)) population. We found that a significant portion of Molly seedlings stressed at 40°C for 6 h during or after the initial Hessian fly larval attack became susceptible to otherwise avirulent insects, whereas unstressed control plants remained 100% resistant. Specifically, 77.8,73.3,83.3, and 46.7% of plants heat stressed at 0,6,12, and 24 h, respectively, after the initial larval attack became susceptible. Biochemical analysis revealed that heat stress caused a transient decrease in 12-oxo-phytodienoic acid, but an increase in salicylic acid accumulation in Molly plants. The change in phytohormones after heat stress and Hessian fly infestation was not observed in ‘Newton,’ a near-isogenic but Hessian fly susceptible wheat line. Instead, heat stress caused a relatively prolonged reduction in palmitoleic acid. The role of phytohormones in heat-induced loss of wheat resistance was discussed.

This study determined the number of spittlebug adults, Mahanarva spectabilis Distant (Hemiptera: Cercopidae), that should be used in selection tests of the forage grass, Brachiaria ruziziensis (Germain and Evrard). In this study, 0, 1, 2, 4, or 8 M. spectabilis adults were kept in plants for 4 or 8 d per experimental plot. After these periods, the insects were removed from the plants and chlorophyll content, damage score, dry weight, fresh weight, and percent dry matter of shoots were evaluated. Chlorophyll content decreased significantly with higher density of M. spectabilis in plants exposed to the pest for 4 or 8 d. Plants that were exposed to eight spittlebugs for 8 d showed a ≈60% loss of chlorophyll content. When the forage was infested with eight adults for 4 d, the average damage score was 3 (50% of the leaf area was affected). The damage score and fresh and dry weights of the forage did not change depending on the exposure time of the plants to the spittlebugs. The percentage of dry matter of the plants infested was higher with the increase insect density and exposure time for all densities. Thus, the minimum recommended number is eight M. spectabilis adults for 4 d in resistance tests of B. ruziziensis to this pest species.

Commercial field corn (Zea mays L.) hybrids transformed to express some or all of the lepidopteran insect-resistant traits present in SmartStax corn hybrids were evaluated for insecticidal efficacy against a wide range of lepidopteran corn pests common to the northern United States, during 2008 to 2011 at locations in 15 states. SmartStax hybrids contain a pyramid of two Bacillus thuringiensis (Bt) derived events for lepidopteran control: event TC1507 expressing Cry1F protein and MON 89034 expressing Cry1A.105 Cry2Ab2. These studies focused on characterization of the relative efficacy of each event when expressed alone or in combination, and compared with non-Bt hybrid. Corn hybrids containing pyramided insecticidal proteins Cry1F Cry1A.105 Cry2Ab2 (SmartStax) consistently showed reduced plant feeding damage by a wide range of lepidopteran larvae compared with single event and non-Bt hybrids. Corn hybrids expressing TC1507 or MON 89034 as single or pyramided events were consistently efficacious against Ostrinia nubilalis (Hiibner). SmartStax hybrids had less injury from Agrotis ipsilon (Hufnagel) and Striacosta albicosta (Smith) than corn hybrids containing only event MON 89034 but were not more efficacious than single event TC1507 hybrids. Corn hybrids with event MON 89034 provided better control of Helicoverpazea (Boddie), than event TC1507 alone. Spodoptera frugiperda (J.E. Smith) efficacy was higher for hybrids with pyramid events and single events compared with the non-Bt hybrids. The spectra of activity of events TC1507 and MON 89034 differed. The combination of TC1507 MON 89034 provided redundant control of some pests where the spectra overlapped and thereby are expected to confer a resistance management benefit.

The cereal leaf beetle, Oulema melanopus (L.) (Coleoptera: Chrysomelidae), which is Eurasian in origin, is an emerging pest of agriculturally important cereal crops in western Canada, including wheat, oat, and barley. Among these crops, wheat (Triticum aestivum L.) has the highest number of resistant genotypes to O. melanopus infestation. Here we explored six genotypes from central Asia with putative resistance to the beetle in comparison with a widely grown Canadian wheat variety. We noted the highest oviposition on the susceptible control genotype, CDC GO, and the lowest on one of the central Asian genotypes (NN-100) in both choice and no-choice tests. Two of the other Asian genotypes (NN-78 and NN-105) were also less attractive for oviposition than theCDC GOcheck. Feeding trials also indicated less damage on some of the Asian genotypes (NN-100, NN-105, and NN-78) relative to CDC GO, but other Asian genotypes (NN-41, NN-45, and NN-27) were highly attractive for feeding and oviposition and did not exhibit stronger resistance to O. melanopus infestation than moderately resistant central Asian genotypes (NN-103, NN-78, or NN-105). There were no significant differences in the amount of feeding by overwintered and teneral adults. The results indicated that some wheat genotypes developed in central Asia have categories of nonpreference for feeding and oviposition worth considering in further development of host-plant resistance and integrated management of this pest.

Hessian fly, Mayetiola destructor (Say, 1817), is a major pest of wheat, and is controlled mainly through deploying fly-resistant wheat cultivars. The challenge for the plant resistance approach is that virulence of Hessian fly populations in the field is dynamic, and wheat cultivars may lose resistance within 6 - 8 yr. To ensure continuous success of host plant resistance, Hessian fly populations in the field need to be constantly monitored to determine which resistance genes remain effective in different geographic regions. This study investigated five Hessian fly populations collected from Texas, Louisiana, and Oklahoma, where infestation by Hessian fly has been high in recent years. Eight resistance genes, H12, H13, H17, H18, H22, H25, H26, and Hdic, were found to be highly effective against all tested Hessian fly populations in this region, conferring resistance to ≥80% of plants containing one of these resistance genes. The frequencies of biotypes virulent to resistance genes H13 (biotype vH13), H18 (vH18), H21 (vH21), H25 (vH25), H26 (vH26), and Hdic (vHdic) were determined, and were found to vary from population to population, ranging from 0 to 45%. A logistic regression model was established to predict biotype frequencies based on the correlation between the percentages of susceptible plants obtained in a virulence test and the log-odds of virulent biotype frequencies determined by a traditional approach.

Switchgrass, Panicum virgatum L., is being developed as a bioenergy feedstock. The potential for large-scale production has encouraged its evaluation as a host for important grass pests. Eight no-choice studies were performed for two developmental stages of two switchgrass cultivars (‘Kanlow’ and ‘Summer’) and two experimental strains, K×S, and S×K produced by reciprocal mating of these cultivars followed by selection for high yield. Plants were evaluated for host suitability and damage differences to herbivory by four important cereal aphids, Sipha flava (Forbes), Schizaphis graminum (Rondani) (biotype I), Rhopalosiphum padi (L.), and Diuraphis noxia (Mordvilko). All switchgrasses were found to be unsuitable feeding and reproductive hosts to R. padi and D. noxia, which were unable to establish on the plants. However, both S. flava and S. graminum were able to establish on all switchgrasses tested. Differential levels of resistance to S. flava and S. graminum were detected among the switchgrasses by both cumulative aphid days (CAD) and plant damage ratings. Kanlow was consistently rated as highly resistant based on CAD and damage ratings for both aphid species, while Summer was consistently among the most susceptible to both aphids at both developmental stages, with relatively high damage ratings. The resistance of the K×S and S×K populations in relationship to their Summer and Kanlow parents indicted that they inherited some resistance to S. graminum and S. flava from their Kanlow parent. These studies provide valuable baseline information concerning the host suitability of switchgrass to four cereal aphids and the plant-insect interactions within a system that has been largely overlooked and indicate that there are genetic differences among switchgrass populations for resistance to some insects.

We developed a computer program for life table analysis using the open source, free software programming environment R. It is useful to quantify chronic nonlethal effects of treatments on arthropod populations by summarizing information on their survival and fertility in key population parameters referred to as fertility life table parameters. Statistical inference on fertility life table parameters is not trivial because it requires the use of computationally intensive methods for variance estimation. Our codes present some advantages with respect to a previous program developed in Statistical Analysis System. Additional multiple comparison tests were incorporated for the analysis of qualitative factors; a module for regression analysis was implemented, thus, allowing analysis of quantitative factors such as temperature or agrochemical doses; availability is granted for users, once it was developed using an open source, free software programming environment. To illustrate the descriptive and inferential analysis implemented in lifetable.R, we present and discuss two examples: 1) a study quantifying the influence of the proteinase inhibitor berenil on the eucalyptus defoliator Thyrinteina arnobia (Stoll) and 2) a study investigating the influence of temperature on demographic parameters of a predaceous ladybird, Hippodamia variegata (Goeze).

Aerosol insecticides are commonly used for management of stored-product pests inside food facilities, but the physical complexity of the interior of most food facilities may influence the dispersal and deposition of droplets and create spatial variation in dosage. The spatial pattern in aerosol deposition was evaluated inside a flour mill using a high density grid of bioassay insects. Three insecticides, Aero tech with NyGuard and Pyrocide 100 Diacon II, both pyrethrin and insect growth regulator combinations, and Vap20, an organophosphate, were evaluated at normal (27°C) and high (40°C) target temperatures. Using a newly developed efficacy index, there was spatial pattern to aerosol deposition detected for the pyrethrin insecticides and the pattern differed between aerosols and temperatures. Walls and corners, especially behind the direction of application, were especially vulnerable to zones of lower efficacy, and open areas in center of the room tended to have the highest efficacy. The organophosphate insecticide provided complete efficacy at all bioassay dish locations, probably due in part to its vapor toxicity. Using boxes 1 m in depth and 5, 10, or 20 cm in height and open on only one end, it was shown that aerosol dispersal under horizontal surfaces could be impacted by gap height, aerosol, and temperature. These results show the potential for spatial variation in aerosol efficacy within a food facility and identify locations with the potential to receive a lower insecticide dosage. To increase overall efficacy, these locations may be targeted for additional interventions to provide more uniform pest population suppression.

We used the red flour beetle, Tribolium castaneum Herbst (Coleoptera: Tenebrionidae), to compare three feeding bioassay techniques using flour disks. The area (scanner or digital photographs) and mass (sensitive balance) of the same flour disks were measured daily for 1 or 2 wk to assess feeding by insects. The loss in mass and area over 4 h was measured, as some variation over time was noticed in the disks with no insects feeding on them. The gravimetric method correlated well with both measurements of the area for the disks held in a growth chamber: scanner (R² = 0.96), digital photography (R² = 0.96). There was also a high correlation (R² = 0.86) between the disk weight and area scanned at normal lab conditions. There were differences in the percentage of the disks remaining over time depending on the temperature and whether they were weighed or scanned. Measuring the mass of the disks resulted in a relatively larger percent of disk remaining compared with the scanned area. Mass measurements required a sensitive balance, handling of the disks and the insects, and appeared slightly more sensitive to humidity and temperature changes over time. Scanning the disks requires flat bed scanner access but less handling of both insects and disks. Digital photographs could be taken quickly, requiring less equipment, although photographs had to be further processed to determine area. Scanning or taking digital photographs of flour disk area was an effective technique for measuring insect feeding.

Aerosol insecticides are being used in flour mill pest management programs, but there is limited information on their efficacy on different insect life stages. In this study, we evaluated the efficacy of synergized pyrethrin applied as an aerosol against eggs, larvae, pupae, and adults of the red flour beetle, Tribolium castaneum (Herbst), and the confused flour beetle, Tribolium confusum Jacquelin du Val. Effects of direct and indirect exposure were evaluated by exposing each life stage to the aerosol and then transferring to untreated flour, transferring untreated insects to treated flour, or exposing both the insects and the flour to the aerosol. The aerosol produced >88% mortality of both species and all life stages when insects were directly treated and transferred to either treated or untreated flour. Mortality was significantly reduced when insects were either treated together with flour or untreated insects were transferred to treated flour (indirect exposure to the aerosol). Larvae and adults of both species were more tolerant compared with eggs and pupae. Recovery of moribund adults in the indirect exposure treatments was greater compared with recovery of moribund insects in the direct exposure treatments. Good sanitation before aerosol application could facilitate direct exposure of insects and thus increase aerosol efficacy inside flour mills.

Traps baited with pheromones are used to monitor the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae), populations in flour mills to aid in making pest management decisions, but the factors that influence T. castaneum movement are not fully understood. We investigated the impact of photoperiod, light intensity, temperature, and relative humidity on flight initiation. The percentage of adults initiating flight reached a maximum at 30–35°C, and then fell to zero at 22.5 and 45°C. Only 2% of beetles flew in complete darkness, and the number of beetles initiating flight increased to 41% under 18 h of light and then decreased slightly to 37% under 24 h of light. Rates of flight initiation did not vary with light intensities from 1,784 to 4,356 lux or relative humidities from 25 to 85%. Thus, temperature and photoperiod are the main abiotic factors tested that impact flight initiation in T. castaneum, which have broad ranges of temperatures and photoperiods over which they can fly. The current results should be useful in helping to interpret trap catches based on abiotic conditions during the trapping period, and the results should be useful in helping to understand T. castaneum movement outside grain storages and processing facilities and their potential to infest structures.

Three attract-and-kill formulations, a gel, a wax panel, and a plastic cylinder were tested in simulated warehouses at three densities of devices and at three densities of moths, Plodia interpunctella Hübner, per room. Wax panels and the cylinder formulations suppressed all the densities of moths with only one device per room. Two field experiments were then conducted during 2005 and 2006 in replicated commercial pet food and grocery stores that harbored natural populations of P. interpunctella. In the summer of 2005, the wax panel formulation suppressed adult male response to monitoring traps and also reduced the numbers of larvae in food bait oviposition cups after the first month of being established. This suppression was maintained until the third month. The second field experiment in 2006 compared three pheromone-based methods of moth suppression in buildings with moth populations in untreated buildings. The mass-trapping treatment showed the lowest adult moth capture after the first month of the experiment until the end of the third month. However, this treatment was similar statistically to use of attract-and-kill panels, mating disruption, and untreated control establishments in most of the weeks. Monitoring of larvae in food cups revealed the pheromone- based methods were not significantly different from each other, but that they suppressed moth populations in most of the weeks when compared with untreated control buildings. This research shows potential for successful pheromone-based suppression methods for Indianmeal moths in commercial applications.