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Conogethes punctiferalis (Guenée) (Lepidoptera: Crambidae) is one of the most damaging Lepidoptera, attacking fruit in the temperate and tropical regions of Asia, Australia, and Papua New Guinea. Effective methods of control will likely remain limited until further physiological and ecological studies can be conducted, many of which will require effective means of rearing of the insect in the laboratory. To that end, this study was undertaken to develop and assess four meridic diets for rearing C. punctiferalis. The four diets differed in the amounts of chestnut meal, corn meal, and soybean meal. The diet containing 30 g chestnut meal, 70 g corn meal, and 70 g soybean meal per 700-ml diet yielded a larval survival rate of 94.5%, a generation developmental time of 42.4 d, mean pupal weights of 73.6 mg for males and 77.3 mg for females, and an adult fecundity rate of 97.9 eggs/female. Performance on this diet compared favorably with rearing on fresh corn.
Molecular gut-content analysis has revolutionized the study of predator–prey interactions and yielded important insights into arthropod community processes. However, the raw data produced by most gut-content assays cannot be used to assess the relative impact of different predator taxa on prey population dynamics. They must first be weighted by the detectability half-lives for molecular prey remains for each predator–prey combination. Otherwise, interpretations of predator impact will be biased toward those with the longest detectabilities. Molecular ecologists have noted taxonomic trends in the length of the half-life, in particular that they tend to be longer in spiders, staphylinids, and true bugs. We compare new data from feeding trials of two previously untested true bugs, Geocoris punctipes (Say) (Lygaeidae) and Orius insidiosus (Say) (Anthocoridae), with those from four other heteropterans and three coleopterans, in order to test the hypothesis that half-lives tend to be longer in predatory Heteroptera than in predators of other groups. At 18.4 h and 21.8 h, respectively, the new half-lives are statistically longer than those of the adult beetles, statistically indistinguishable from that of larval Coleomegilla maculata (DeGeer), and statistically shorter than three of the four previously published heteropteran half-lives. If only adults are considered, heteropterans and coleopterans are separable, but the range is still so large that there are multiple statistical differences among the half-lives, making generalization at the order level unsupportable. The hypothesis is rejected.
Mole crickets (Orthoptera: Gryllotalpidae) damage warm-season turfgrasses throughout the southeastern United States. The two most destructive species are the southern mole cricket, Scapteriscus borellii Giglio-Tos, and the tawny mole cricket, S. vicinus Scudder. Both species use mating calls to attract and locate potential mates. Male mating calls have often been used to distinguish among different species of crickets. Calling characteristics can vary within a species due to numerous factors, including climate. There has been no research conducted on the call characteristics of mole crickets as they have expanded their range of inhabitance to North Carolina. Male calls of southern and tawny mole crickets were recorded at night in 2009 and 2010. Analysis of the calls indicated that there was little change in the calling characteristics from previous research. This allows us to continue to expand our management plans for this pest and coordinate our efforts with other regions where mole crickets are located.
Honeydew produced by homopteran insects, such as aphids, whiteflies, and mealybugs, can be abundant in some crops and may represent an important food resource for spiders and other honeydew-feeding natural enemies. Woolly whiteflies (Aleurothrixus floccosus [Homoptera: Aleyrodidae]) are common in south Texas citrus, and spiders consistently compose a large percentage of the predatory arthropods in citrus and may benefit from honeydew resources. Feeding on woolly whitefly honeydew was assayed for its contribution to spider survival for five species from different arachnid families. When provided with whitefly honeydew, survival of all five species was significantly better than when provided water alone. However, the level of improvement in survival varied significantly among species. Honeydew supplementation increased survival by 73.5% for Apollophanes punctipes (Cambridge, O. P) (Philodromidae) (32.1 versus 18.5 d on water alone), 266.7% for Cesonia bilineata (Hentz) (Gnaphosidae), 352.6% for Dictyna sp. near bellans hatchi (Dictynidae), 130.9% for Thiodina sylvana (Hentz), and 1,102.5% for Hibana futilis (Banks) (Anyphaenidae) (48 versus 4 d on water alone).
Helicoverpa armigera (Hübner) is a notorious pest of various field crops. A contributing factor in its pest status is the development of resistance to insecticides, making the insect difficult to control. The objective of this study was to assess the toxicity of selected insecticides against natural populations of H. armigera in Pakistan and thus identify possible levels of insecticide resistance. Insects were collected from three locations in the province of Punjab, Pakistan, in three consecutive years. The median lethal concentration (LC50) of selected insecticides was determined for each field population as well as a susceptible lab strain designated as Lab-PK. Resistance ratios (RRs) for each insecticide were calculated as the ratios of the LC50 for each field population relative to that of the Lab-PK strain. Based on the calculated RRs, the field populations tested were highly resistant to bifenthrin (RR = 34.1 to 48.0), moderately to highly resistant to lambda-cyhalothrin (RR = 19.6 to 68.2) and deltamethrin (RR = 19.3 to 37.2), and minimally to moderately resistant to profenofos (RR = 9.80 to 12.11), methoxyfenozide (RR = 6.0 to 11.8) and thiodicarb (RR = 5.6 to 11.5). Resistance was low for emamectin benzoate (RR = 1.7 to 5.2), chlorpyrifos (RR = 3.5 to 9.6), and lufenuron (RR = 1.0 to 2.2). Pairwise comparison of the log LC50 of the insecticides against all populations showed a correlation among the various insecticides, suggesting possible development of cross-resistance.
Certain plant-derived essential oils are classified as ‘minimum risk' pesticides that require no registration with the Environmental Protection Agency and, therefore, have become attractive in formulations of pest-control products. In Petri dish assays, fumigation of a pyrethroid-susceptible strain of bed bugs, Cimex lectularius L. (Hemiptera: Cimicidae), with various essential oils results in mortality that approaches or equals 100% after 5 d. However, when bed bugs were exposed to the same essential oils in sealed, commercial trash bags for 5 d, only rosemary oil killed greater than 99% of the bed bugs. These results are compared with a commercial product that contains cold-pressed neem oil that killed 100% of the exposed bed bugs in both the Petri dish and trash bag studies.
Injury to sunflower blossoms by the European sunflower moth, Homoeosoma nebulella Denis & Schiffermüller, significantly diminishes the harvest of sunflower seeds per hectare in commercial production in the Ganja-Ghazakh crop-growing region of the Republic of Azerbaijan. Annual seed losses of ~460 kg/ha can occur. Economic thresholds (ET), at which time insecticides or other remedial actions should be used to avoid exceeding the economic injury level (EIL), were determined for each of the two generations of H. nebulella that occur annually. The EIL was five to six eggs or large (≥third instar) larvae per blossom for the first generation, or about one egg or small (first or second instar) larvae per blossom for the second generation. The ET for adults caught in pheromone traps was 25.7 per day for the first generation and 3.7 per day for the second generation. Results also indicate that preventative or remedial actions should be used against the second generation of this pest, but such actions do not appear necessary to limit damage caused by the first generation.
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