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Trapping studies were conducted in 2 Florida locations to determine if 3 Old World Spodoptera Guenée species were present. Commercially-produced lures for S. exempta (Walker), S. littoralis (Boisduval), and S. litura (F.), plus a S. litura lure made by the USDA-APHIS-CPHST laboratory at Otis ANGB in Massachusetts, were used with plastic Unitraps and placed near 2 orchid nurseries in Lake and Miami-Dade counties. One S. litura male moth was identified from collections made in Apr 2007; no other exotic species were found in either location. However, thousands of resident species were collected, including S. albula (Walker) (= S. sunia Guenée), S. dolichos (F.), S. eridania (Stoll), S. exigua (Hübner), (J. E. Smith), and S. pulchella (Herrich-Schäffer). This study exposed the amount of labor and level of technical knowledge needed for scientists involved in finding exotic Spodoptera species.
Fall armyworm, Spodoptera frugiperda (J. E. Smith), and corn earworm, Helicoverpa zea (Boddie), perennially cause leaf and ear damage to corn in the southeastern United States. Transgenic hybrids expressing the Cry1Ab (MON810 event) or Cry 1F (TC1507 event) insecticidal endotoxin from Bacillus thuringiensis (Bt) were evaluated for management of fall armyworm and corn earworm in central Georgia during 2006 and 2007. Corn was planted at the recommended time in mid-Apr and in late Jun to simulate a double-crop corn planting. Both Bt events reduced whorl infestation and damage by fall armyworm, but TC1507 provided greater protection from whorl injury than MON 810 under severe fall armyworm infestations. Hybrids with the MON810 event usually had less ear infestation by corn earworm than susceptible hybrids, whereas the TC1507 event usually did not reduce ear infestations. Nevertheless, both events prevented ear damage, but there was no consistent difference between the two Bt traits in preventing ear damage. Bt traits did not affect grain yield in either year during the first planting when fall armyworm infestations were low. Both events prevented significant yield loss during the second planting in 2006 when whorl infestation levels exceeded 50% in susceptible hybrids. Because of the greater activity in preventing whorl damage by fall armyworm, the TC1507 event would be useful in mitigating the risk of severe lepidopteran damage to later plantings of field corn for grain production in the southeastern U.S.
Transgenic cottons containing the Bollgard®, Bollgard II® and WideStrike® traits were grown in 2005 and 2007 to examine the efficacy against beet armyworm Spodoptera exigua (Hübner) and fall armyworms S. frugiperda (J. E. Smith). Results suggest that both dual-gene traits are more efficacious against these armyworm species than Bollgard®. In these studies, WideStrike® appears to be more efficacious against fall armyworms than Bollgard II®, while Bollgard II® is more efficacious against beet armyworms than WideStrike®. Possible reasons for these differences in efficacy are discussed.
To assess both foliage- and ear-feeding insect resistance in the same maize inbred lines, fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) resistance at the seedling stage was examined in 6 corn inbred lines, including 4 CIMMYT maize inbred lines (CML333, CML335, CML 336, and CML338) with varying levels of silk maysin that confers corn earworm, Helicoverpa zea (Boddie), resistance and controls (fall armyworm-resistant Mp708 and susceptible AB24E). Fall armyworm injury rating and chlorophyll content were examined under greenhouse and field conditions. Plant height, plant stem circumference, and photosynthesis-related measurements were recorded on uninfested and infested plants only under greenhouse conditions. Injury ratings on CML333, CML336, and CML338 (with a range of low to high levels of silk maysin) were the same as for the resistant control (Mp708), and were significantly lower than for the susceptible control AB24E and CML335 (without silk maysin). Plant height, plant stem circumference, and chlorophyll content varied among the 6 inbred lines, but were not consistently correlated to resistance at the seedling stage. Photosynthetic rate was negatively affected by injury in AB24E, CML333, CML335, and CML336, but not affected in CML338 and Mp708. The reduction in photosynthetic rate of fall armyworm-susceptible AB24E, and in resistant CML333 and CML336 indicated that insect resistance in CML333 and CML336 might not be related to photosynthetic rate. At the same time, the data suggest that CML338 and Mp708 were tolerant to herbivory because no difference in either photosynthetic rate or photosynthetic capacity was detected in either inbred line between uninfested and injured corn seedlings. Further examination of photosynthetic capacity based on A/Ci and light response curves supported this resistance mechanism categorization. This experiment indicated that corn earworm-resistant corn inbred lines with varying levels of silk maysin could confer resistance to foliage-feeding fall armyworm at its seedling stage.
The fall armyworm, Spodoptera frugiperda (J. E. Smith) is a significant economic pest in the western hemisphere, causing substantial losses in corn, sorghum, forage, and turf grasses. Although fall armyworm does not survive severe winters, it infests most of the central and eastern United States and Canada because of annual migrations from overwintering sites in Florida and Texas. A detailed description of these movements is a prerequisite for identifying the factors that determine the timing and direction of migration and for developing models that can predict the severity of infestations at the migratory destinations. Complicating this effort is genetic heterogeneity within the species, which increases phenotypic variability. Particularly important are 2 “host strains”, defined by a preferential association with either large grasses (designated corn-strain), such as corn and sorghum, or smaller grasses (designated rice-strain), such as rice and bermudagrass. This paper reviews recent studies examining the genetic complexity of fall armyworm populations, including characteristics of the 2 strains and the possibility of subgroups within strains. The use of this information to monitor short and long distance movements is discussed.
M. Willrich Siebert, J. M. Babock1, S. Nolting, A. C. Santos, J. J. Adamczyk Jr., P. A. Neese, J. E. King, J. N. Jenkins, J. McCarty, G. M. Lorenz, D. D. Fromme, R. B. Lassiter
Efficacy of maize, Zea mays L., hybrids and cotton, Gossypium hirsutum (L.), varieties expressing Cry1F insecticidal crystal protein of Bacillus thuringiensis (Bt) var. aizawai Berliner (transformation event TC1507 in corn and event DAS-24236-5 in cotton) was evaluated for control of fall armyworm, Spodoptera frugiperda (J.E. Smith). Control of natural and artificial fall armyworm infestations of eggs and various larval stages to 3 Cry1F and non-Bt maize isoline pairs at V4-V7 corn growth stage was evaluated at 10 locations across the United States and Brazil. Varieties producing the Cry1F protein provided high levels of control. Furthermore, control provided by Cry1F-maize hybrids was frequently better than when fall armyworm were managed with 3 applications of foliar insecticides. Efficacy of transgenic Cry1Ac:Cry1F cotton against fall armyworm was evaluated for 5 varieties during anthesis in laboratory and natural infestation field studies in the southern United States. Laboratory colonies of fall armyworm originally collected from corn, bermudagrass, Cynodon dactylon (L.), cotton, and royal paulownia, Paulownia tomentosa (Thunb.) and determined to be either the rice or corn-associated host strain, all resulted in low levels of survival when fed matures leaves of Cry1Ac:Cry1F-cotton. In natural infestation studies, levels of fall armyworm in squares (flower buds), flowers, and bolls (fruit), were significantly lower in cotton containing Cry1F as compared to non-Bt cotton. These results demonstrate that maize hybrids and cotton varieties containing Cry1F can be an important component in an overall management program for fall armyworm across a broad range of geographies and crops.
Survival assays were conducted with beet armyworm Spodoptera exigua (Hübner) and southern armyworm S. eridania (Stoll) with tropical soda apple Solanum viarum Dunal, a relative of tomato. In addition, polyphenol oxidase (PPO) enzyme assays were conducted to determine if plant defense compounds are being produced by tropical soda apple in response to herbivory. Both S. exigua and S. eridania induced plant defenses in tropical soda apple. Significantly more S. exigua and S. eridania neonate larvae survived to 2nd instar on non-induced plants and artificial diet when compared with plants with induced defenses. Tropical soda apple plants fed on by S. exigua and S. eridania had significantly increased PPO activity.
From 2004 through 2005, plots of experimental transgenic cotton lines containing the vegetative insecticidal protein, Vip3A; δ-endotoxin, Cry1Ab; and both Vip3A and Cry1Ab were evaluated for efficacy against certain lepidopteran pests. Results showed that the cotton line containing Vip3A was more efficacious against the beet Spodoptera exigua (Hübner) and fall armyworm Spodoptera frugiperda (J. E. Smith) compared to the Cry1Ab cotton line; however, the Cry1Ab cotton line was more efficacious against the tobacco budworm Heliothis virescens F. compared to the cotton line containing Vip3A. Both the Vip3A and Cry1Ab cotton lines provided similar mortality against the bollworm Helicoverpa zea (Boddie). No synergism between Vip3A and Cry1Ab was observed.
Flowers of the butterfly bush, Buddleja davidii Franch., are visited by butterflies as well as other insects. Night captures revealed also that moths visit butterfly bush flowers. Moths captured in traps over flowers included 12 species of Noctuidae, 6 species of Pyralidae, 2 species of Geometridae, and 1 tortricid species. The majority of moths trapped at these flowers were cabbage loopers, Trichoplusia ni (Hübner), and alfalfa loopers, Autographa californica (Speyer). Both males and females were captured at butterfly bush flowers. Additionally, butterflies, bees, wasps, flies, and other insects also were captured. Analysis of volatile compounds collected from air over clusters of butterfly bush flowers yielded the consistent presence of nine chemicals: benzaldehyde, 6-methyl-5-hepten-2-one, hexyl acetate, 4-oxoisophorone, (E,E)-α-farnesene, (Z)-cinnamaldehyde, dihydrooxoisophorone, β-cyclocitral, and oxoisophorone oxide. Emitted amounts of these floral odorants averaged 57 ng per h per floret or 21 μg per h per flower cluster (raceme). Five of those floral chemicals, benzaldehyde, 4-oxoisophorone, dihydrooxoisophorone, oxoisophorone oxide, and (E,E)-α-farnesene triggered antennal responses in cabbage looper moths, while benzaldehyde, oxoisophorone oxide, and 4-oxoisophorone also stimulated antennal responses in alfalfa looper moths. Some of these compounds may be attractants or co-attractants for moths and play a key role in locating flowers as nectar sources.
Banker plants with Aphidius colemani Viereck were tested in greenhouses in Massachusetts and New York for control of cotton aphid Aphis gossypii Glover, and green peach aphid Myzus persicae (Sulzer) on 2 spring flower crops, pansies (Viola tricolor hortensis) and Marguerite daisies (Argyranthemum hybrid). Banker plants consisted of pots of barley plants infested with the bird cherry-oat aphid Rhopalosiphum padi (L.), inoculated at the start of the crop with adults of A. colemani purchased from a commercial insectary. Initial trials were conducted in University of Massachusetts greenhouses containing flats of the crop plants. Sentinel plants in flats were infested uniformly with aphids, and particular greenhouses were subjected to the presence of banker plants or left as controls. Prior to University trials, a survey was conducted in commercial greenhouses in Massachusetts and New York to determine the frequency and species of aphid infestation in spring flower crops. After University trials, the efficacy of banker plants was tested in commercial greenhouses in both states. In surveys of commercial greenhouses, M. persicae was the most frequently detected species, accounting for 53% of all infestations. In University greenhouse trials, in absence of parasitism, A. gossypii increased fastest on daisy, followed by M. persicae on daisy, M. persicae on pansy, and A. gossypii on pansy. Parasitoid suppression of population increase was strongest for A. gossypii on daisy and poorest for M. persicae on pansy. The presence of 2 aphid species in the same greenhouse did not alter the level of biological control in our trial. In commercial greenhouses, banker plants failed to control M. persicae deployed on infested pansies as sentinel hosts. In the laboratory, a 12-h exposure to dried residues of pyriproxyfen or pymetrozine, insecticides commonly used to control aphids, reduced survival of A. colemani adults, compared to a water control (82% survival), to 71% and 53%, respectively. Adult parasitoid emergence from pesticide-treated aphid mummies was reduced from 68% for the controls to 56% for pyriproxyfen and 62% for pymetrozine.
The fall armyworm Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), is a destructive pest of many species of both C3 and C4 (cool- and warm-season) turfgrass. No-choice experiments were conducted to evaluate 13 turfgrass genotypes of various Poa spp. for susceptibility or resistance to the fall armyworm. All 13 genotypes, including 8 Texas bluegrass (Poa arachnifera Torr.), 2 Kentucky bluegrass (P. pratensis L.) and 3 Kentucky bluegrass × Texas bluegrass interspecies hybrids, were antibiotic and produced an accumulated >80% mortality of neonate larvae before they pupated. ‘Reveille’ (a hybrid) provided 100% antibiosis of larvae within 4 d of feeding. When 4-d-old fall armyworm larvae that had first fed on a susceptible Poa host were confined on the same 13 Poa genotypes as in the neonate test, a much higher survival rate was recorded. ‘Reveille’ produced 94.4% mortality after 3 d of feeding and 100% mortality after 8 d of feeding, while TXKY90-13-16 (another hybrid) provided 100% mortality of larvae within 13 d of feeding. A third hybrid, TXKY90-13-8 was one of the more susceptible genotypes. For the 4-d-old larvae, ‘Baron’ and ‘Delwood Fine’ Kentucky bluegrass provided only 50 and 22.2%, respectively, mortality after 8 d of larval feeding and did not produce 100% mortality until pupation. Also, mortality of larvae on the 8 Texas bluegrass genotypes produced ≤45% maximum accumulated mortality by pupation or adult emergence. ‘Laser’ rough bluegrass (P. trivialis L.) is an excellent host with ≤5.6% larval mortality.
The recently described Mexican parasitic wasp Eurytoma sivinskii Gates and Grissell (Hymenoptera: Eurytomidae), attacks Anastrepha obliqua (Diptera: Tephritidae) pupae in the soil. The life cycle (egg to adult) is completed in 23.1 (± 2.1) d (mean ± S.E.) at 27 ± 2°C. Females were capable of superparasitism and laid 1-8 eggs per host (2.59 ± 1.56, mean ± S.E.), but invariably only 1 adult parasitoid emerged. Oviposition occurred primarily in the medial and posterior portions of the host. Eurytoma sivinskii is ectoparasitic since 100% of the eggs are laid within the internal cavity of the puparium and on the surface of the pupa of the host fly. In no case were first and second instars parasitized. However, 1 third-instar out of 625 fly pupae exposed, yielded a single parasitoid per host. Eight-day-old pupae yielded the most parasitoids although females laid eggs in 1-d- to 14-d-old pupae. There were no significant differences in rates of parasitism among female E. sivinskii of different ages. Adults derived from eggs laid in the posterior region developed more rapidly, but adult sex ratio and percent of emergence were the same in both posterior and medially laid eggs. Regardless of oviposition location, adults were more likely to emerge through the middle of the puparium.
This paper presents the first descriptions of 2 distinct behaviors of the Tupelo leafminer, Antispila nysaefoliella Clemens (Lepidoptera: Heliozelidae). Through the use of specialized morphological structures, the leafminers use these behaviors to generate substrate-borne vibrations that can be emitted as audible sounds to humans. Scanning electron micrographs of these structures are presented. In 1 behavior, the larvae “tick” their abdomens back and forth rhythmically; and in the other, they “rattle” their abdomens in short rapid pulses. These are named for the sounds produced. Previous studies have shown that parasitoids emit substrate vibrations while walking and probing during their search for hosts from the leaf surface. The experimental results show that the larvae of A. nysaefoliella are sensitive to vibrational stimuli in general by “wriggling to all frequencies”, but “ticked” only to some frequencies which are characteristic of parasitoid probing behavior, and “rattled” rarely.
The acute toxicity of the adjuvants Silwet L-77 and Kinetic, alone and in combination with petroleum oil and copper hydroxide, to the Asian citrus psyllid Diaphorina citri Kuwayama was evaluated in screenhouse bioassays. In addition, the acute and residual toxicity of Silwet L-77 and Kinetic, alone and in combination with petroleum oil, copper hydroxide, imidacloprid, and abamectin, to the parasitoid Tamarixia radiata (Waterston) were evaluated under laboratory conditions. In screenhouse trials, Silwet L-77 (0.05%) was more insecticidal than Kinetic (0.05%) and increased the toxicity of both petroleum oil and copper hydroxide to D. citri. Petroleum oil at reduced rates (0.5 and 1%) in combination with Silwet L-77 or Kinetic was less effective in reducing D. citri populations than petroleum oil at 2% in combination with these adjuvants. Petroleum oil at 2% plus Silwet L-77 was the most toxic combination to D. citri eggs, young (first- and second- instars) and mature nymphs (third- to fifth-instars), and adults (81, 83, 74, and 55% mortality, respectively). Copper hydroxide was only toxic to young nymphs when combined with Silwet L-77 (64.9% mortality). Under laboratory conditions, survival of T. radiata was reduced by the residual effects of imidacloprid (>95% mortality) and by the acute toxicity of abamectin (>91% mortality). Silwet L-77 and Kinetic alone, and petroleum oil and copper hydroxide alone or in combination with these adjuvants, had low residual and acute toxicity to the parasitoid and appear to be compatible with the biological control of D. citri by T. radiata. The results of this study suggest that Silwet L-77 may be used in a citrus IPM program in combination with petroleum oil or copper hydroxide to increase psyllid control while spraying to suppress other insect pests or plant diseases. Field trials should be conducted to evaluate the effectiveness of these products against D. citri and their impact on T. radiata populations.
Many adult hymenopterous parasitoids feed on floral nectar, and occasionally pollen. However, flowers differ in both accessibility and attractiveness to these insects. Malaise traps, a type of “passive/interception” trap, were baited with potted flowering plants, Lobularia maritima L. (Brassicaceae) or Spermacoce verticillata L. (Rubiaceae), or left unbaited as controls. These plants have different floral structures, but both have been previously used as food-plants for biological control agents. In general, L. maritima captured more Braconidae, particularly Opiinae, than either alternative. Species of this subfamily attack Diptera and certain species are important natural enemies of pest Tephritidae. The roles of plant attractiveness (volatiles) and architecture (trap access) are discussed, as is the possibility of employing L. maritima and/or its productsin monitoring or maintaining fruit fly parasitoids.
As part of an evaluation of the braconid parasitoid Diachasmimorpha longicaudata (Ashmead) as a biocontrol agent of Ceratitis capitata (Wiedemann) in Brazil, the aims in the current study were to find the best parental ratio of females to males in the rearing cages in order to get the highest female biased offspring in the parasitoid rearing process, and to verify the parasitism efficiency on C. capitata according to parental female densities. Three treatments were assessed: T1 (20 females: 20 males), T2 (60 females: 20 males) and T3 (100 females: 20 males). Ten late-third instars of C. capitata were offered daily to each female parasitoid from the 1st to the 12th d of age. The parental female productivity, fecundity, offspring sex ratio, percentage of parasitoid emergence, and daily mortality of parental females and males at different female/male densities were evaluated. The results indicated that numbers higher than 20 parental females did not affect offspring sex ratio, overall offspring production, nor the percent parasitism. Female biased offspring occurred in all three parental female/male ratios analyzed in this study, except that predominately males developed from parasitoid eggs laid in the age interval 1-2 d post emergence. Higher parasitoid female productivity and fecundity were found at the 1:1 female/male per cage density whereas lower productivity and fecundity were recorded at the 5:1 female/male ratio. Higher female/male ratio in the parental cages increased the mortality rate of females but did not influence the number of parental male deaths. The results may facilitate advancement of an optimum mass-rearing system to aid in control of C. capitata in Brazil.
Examination of more than 600 specimens of Copaeodes minima (W. H. Edwards, 1870) (Hesperiidae: Hesperiinae) indicated phenotypic variation throughout its distribution. A dark form occurs in response to low temperatures during development. Its genitalia do not vary concomitantly. Both C. minima and its synonym, Copaeodes rayata Barnes & McDunnough, 1913, were described from the pale form of the species. A lectotype is designated for Copaeodes rayata.
In this work we report the effect of rainfall on survival of pupae and adults of Anastrepha ludens (Loew) and A. obliqua (Macquart) under semi-field conditions. The influence of 2 soil textures and soil moisture on depth of pupation and pupal survival of both species was studied. There was no statistical difference on depth of pupation between larvae of A. ludens and A. obliqua in both types of soils. Adult emergence of A. ludens was higher than A. obliqua from soils with low moisture, while no significant difference was observed in soils at field capacity and saturation point. In the farm “Alianza” locality (760 masl, 1219 mm of rainfall), adult emergence decreased in direct relation to rainfall (r = 0.956 for A. ludens; r = 0.952 for A. obliqua), but this was not observed in Metapa de Dominguez (120 masl, 1114 mm of rainfall). Rainfall did not have any significant effect on adult mortality (r = 0.038 for A. ludens; r = 0.051 for A. obliqua), even under intense precipitation (120-160 mm/day), which indicates that fruit fly adults are able to find adequate refuge during heavy rain. These results are evidence that rainfall does not exert a significant impact on emergence and survival of adults of these species, and that the yearly fluctuations of their populations are mainly correlated to other factors such as host fruiting phenology.
Five larval diets for laboratory rearing of Bactrocera oleae Gmelin were tested. These diets were based on soy hydrolysate, yeast, sugar, casein, wheat germ, microcellulose and agar. The quality of diets was evaluated by measuring larval and pupal survival, larval and pupal weights, and development times. The best results were obtained with an agar-based diet that was modified from the currently used cellulose-based diet for rearing olive fruit fly in mass rearing facilities. Under these conditions, 77% of the larvae reared on the new agar-based diet completed development and achieved higher pupal weight than larvae reared on the currently available cellulose diet. The average life cycle was completed in 25.2 ± 0.4 d on the agar diet, and other biological parameters were also very close to those on the cellulose diet. Olive fruit fly larvae were reared continuously and successfully for 4 generations on the new diet. The preparation of the new agar-based diet is simple, the cost is low, and it is useful for small-scale laboratory tests and rearing.
Eastern cicada killers, Sphecius speciosus Drury, are large, ground-nesting, mass-provisioning wasps that use cicadas to feed their offspring. Previous studies have reported that female S. speciosus provide each male offspring with 1 or rarely 2 cicadas, and each female offspring with 2 or rarely 3 cicadas, regardless of cicada size. We collected samples of male and female cicada killers and samples of their cicada prey from 12 locations in 10 different states of the USA. We measured right forewing length of the wasps and dry body mass of the cicadas as indicators of size; ANOVA revealed significant differences in mean masses among local populations of cicadas. We predicted that wasp size would also vary among locations, and would be positively correlated with mean size of local cicada prey. ANOVA did reveal significant differences in mean wing length in both male and female wasps among study sites. Regression analysis, with local mean cicada mass as the independent variable and local mean wasp wing length as the dependent variable, suggests that the size of available cicada prey is a good predictor of size for both male and female S. speciosus.
The white grub Laniifera cyclades Druce of prickly pear cactus or nopal is a pest that limits the commercial production of Opuntia. The gregarious larvae perforate the cladodes devouring the inner part, thereby forming large galleries until reaching the central axis of the plant; during their movement through the inner part of the cactus, the larvae make orifices to the exterior to expel their excrements. In this investigation, the virulence of strains BbZ3 and BbZ4 of the entomopathogenic fungus Beauveria bassiana was determined by introducing infested cadavers of Galleria mellonella L. through the orifices on the stem pads of the nopal plant. Both stains of B. bassiana were highly pathogenic causing 100% mortality in the larvae of L. cyclades inside the nopal cladodes in the greenhouse as well in the field. BbZ3 was more virulent with a LT50 of 5.1 d in the greenhouse and 6.4 d in the field, while the LT50 of BbZ4 was 6 and 7.5 d, respectively. The application of larval cadavers of G. mellonella infested with the fungus B. bassiana was an effective control strategy against larvae of L. cyclades.
Antennal morphology and funicular sensilla of male and female papaya fruit fly, Toxotrypana curvicauda Gerstaecker, were studied with light microscopy and scanning electron microscopy. Antennae were 3-segmented, consisting of a scape, a pedicel, a flagellum or funiculus that bears the arista. Antennal segments of males showed a trend toward slightly greater dimensions than those of females, but the differences were not significant. Numerous microtrichia as well as trichoid, basiconic, clavate, and styloconic sensilla were observed on the funiculus, and the sensillar characteristics were similar to those reported for other tephritid species. Males and females did not differ in total number or type of sensilla found on the funiculus, but trichoid and clavate sensilla were significantly larger in females. This difference may be related to female chemoreception of male-emitted sex pheromone and of host plant volatiles.
The ability of the invasive lobate lac scale, Paratachardina pseudolobata Kondo & Gullan, to survive exposure to near or below freezing temperatures (-25, -15, -10, -5, 0, 5, and 10°C) for extended durations (6, 12, 24, 48, and 72 h) was assessed in the laboratory. Exposure at 10°C for 6 to 72 h did not cause significant mortality in immature and adult lobate lac scales. All nymphs and adults were killed after exposure to very low temperatures (-25 to -10°C) for 6 h. All nymphs were killed within 24 h at -5, 0, and 5 oC, while about 2% of adults were still alive after 72 h at 0 and 5°C. Results suggested that the range expansion of the lobate lac scale in the United States will be limited by winter temperature. The lobate lac scale may have a higher potential to invade areas where the average winter temperature do not drop below freezing for an extended duration (3 or more consecutive days), such as southern Florida, Rio Grande Valley in Texas, and Colorado river Delta between California and Arizona.
Cactoblastis cactorum (Berg) is an invasive pest that represents an economic and ecological threat to native cacti in the U. S. and Mexico and that is currently the object of an eradication/control program in both countries. One tactic used to mitigate the threat of this species involves the SIT (Sterile Insect Technique), in which large numbers of larvae are reared on artificial diet or cactus cladodes, preferably the former, and released as sterile adults to mate with wild individuals at or near the leading edge of invasion. We studied combinations of 3 different rearing temperatures (22, 26, and 29°C) and 3 different crowding levels (50, 215, and 500 eggs) to determine percent survival to the adult stage, pupal size of each gender, and fecundity of C. cactorum reared on a factitious meridic diet. Temperature and crowding levels affected survival. The lowest rearing temperature and the low and high crowding levels adversely affect survival. Female pupae were larger than male pupae, and pupal size of males, but not females, was affected by rearing temperature, with smaller male pupae produced at the lowest temperature. Length and width, but not weight, of female pupae were affected by crowding levels, with slightly larger pupae produced at the intermediate level. For both genders, there was significant regression of pupal weight on percent survival, with larger pupae produced from treatment combinations that produced higher percent survival to the adult stage. Number of eggs laid per female was positively correlated with weight of the female as a pupa.
A previous study demonstrated that exposing entire rooms holding mass-reared males of the Mediterranean fruit fly, Ceratitis capitata (Wied.), to the aroma of ginger root oil increased mating success relative to that observed for non-exposed males. Here, we followed the same experimental protocol to test whether the aroma of orange oil similarly enhanced male mating performance. Working at an eclosion facility in California, we exposed trailers (132 m3) containing ≈ 14 million C. capitata males from a genetic sexing (tsl, temperature sensitive lethal) strain to orange oil aroma for 24 h and compared mating success of non-exposed or ginger root oil-exposed tsl males in field-cage trials (in which tsl males competed against males from a standard, bisexual strain for females from this same standard strain). Both orange oil- and ginger root oil-exposed tsl males achieved a significantly greater proportion of the total matings than non-exposed (to any aroma) tsl males. No difference in relative mating success was observed between orange oil- and ginger root oil-exposed tsl males. As orange oil is considerably less expensive than ginger root oil, its use could reduce costs substantially.
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