Seletividade de inseticidas utilizados na cultura da soja ao predador Podisus nigrispinus (Hemiptera: Pentatomidae)

The selectivity of different insecticides to nymphs and adults of Podisus nigrispinus was evaluated in this study. Tests were carried out in the laboratory according to IOBC standard protocol. We evaluated different active ingredients that were applied using a Potter tower. Insect survival was assessed at 24-hour intervals for up to five days after exposure to treatments. Adult survivors of each treatment were assigned to breeding-pairs to evaluate possible effects on fertility. The pyrethroids bifenthrin, zeta-cypermethrin, beta-cyfluthrin, lambda-cyhalothrin and deltamethrin alone or in mixtures with neonicotinoids and diamides, such as beta-cyfluthrin + imidacloprid, lambda-cyhalothrin + thiamethoxan and chlorantraniliprole + lambda-cyhalothrin, as well as the organophosphate, chlorpyrifos, were the most harmful (class 4 classification) insecticides for the preservation of P. nigrispinus for both nymph and adult predators. Conversely, the insecticide growth regulators (IGRs) lufenuron, teflubenzuron, triflumuron, tebufenozide and novaluron were classified as harmful (class 4) only for P. nigrispinus nymphs. These products were classified as harmless (class 1) and slightly harmful (class 2) for adult predators. Among the evaluated products, the most selective for P. nigrispinus were those belonging to the spinosyns (spinosad and spinetoram) and the diamides group (flubendiamide and chlorantraniliprole), which were classified as harmless (class 1) and slightly harmful (class 2) for both P. nigrispinus nymphs and adults. Next, the most selective product was methoxyfenozide, which ranged between slightly harmful (class 2) and moderately harmful (class 3) to nymphs and harmless (class 1) to adults of the natural enemy.A seletividade de diferentes inseticidas para ninfas e adultos de Podisus nigrispinus foi avaliada neste estudo. Os testes foram realizados em laboratório de acordo com protocolo padrão da IOBC. Foram avaliados diferentes ingredientes ativos que foram aplicados usando uma torre Potter. A sobrevivência dos insetos foi avaliada em intervalos de 24 horas por até cinco dias após a exposição aos tratamentos. Os sobreviventes adultos de cada tratamento foram distribuídos em casais para avaliar possíveis efeitos sobre a fertilidade. Os piretróides bifentrina, zeta-cipermetrina, beta-citflutrina, lambda-cialotrina e deltametrina isolados ou em misturas com neonicotinóides e diamidas, tais como beta-citflutrina + imidacloprid, lambda-cialotrina + tiametoxano e clorantraniliprole + lambda-cialotrina, bem como o organofosforado, clorpirifós, foram os inseticidas mais nocivos (classe 4) para a preservação de ninfas e adultos do predador P. nigrispinus. Por outro lado, os reguladores de crescimento de inseticidas (IGRs) lufenuron, teflubenzuron, triflumuron, tebufenozide e novaluron foram classificados como nocivos (classe 4) apenas para ninfas de P. nigrispinus. Estes produtos foram classificados como inofensivos (classe 1) e levemente nocivo (classe 2) para os predadores adultos. Entre os produtos avaliados, os mais seletivos para P. nigrispinus foram aqueles pertencentes às espinosinas (spinosad e spinetoram) e ao grupo das diamidas (flubendiamida e clorantraniliprole) classificados como inofensivos (classe 1) e levemente nocivos (classe 2) para ninfas e adultos de P. nigrispinus. Em seguida, o produto mais seletivo foi methoxyfenozide, que variou entre ligeiramente prejudicial (classe 2) e moderadamente prejudicial (classe 3) para ninfas e inofensivo (classe 1) para adultos do inimigo natural

Biology and nutrition of Spodoptera frugiperda (Lepidoptera: Noctuidae) fed on different food sources

We studied Spodoptera frugiperda development using different food sources in the laboratory and field. Newly hatched larvae were fed soybean, cotton, maize, wheat, and oat leaves. An artificial diet was used as the control. Duration of pre-pupal, pupal, and larva-adult period, pupal weight, sex ratio, survival, larva feeding preferences, oviposition preferences, and nutritional quality of different hosts were evaluated. Insects fed on wheat showed the shortest larva-adult period. The insects fed on cotton and soybean had longer larval development cycles and pupae of lower weight. Feeding preference was evident for third instar larvae and did not differ between wheat, oat, maize, and soybean, which were the preferred hosts. Moths oviposited to a greater extent on the upper canopy of wheat than that of other plants in both the no-choice and free-choice tests. Treatments influenced insect growth, food consumption, and digestion when nutritional variables were analyzed. Thus, grasses were better hosts for S. frugiperda development. Cotton was the least preferred food, followed by soybean. The present study can improve our understanding of S. frugiperda in these different crops and help in developing management strategies. Even though S. frugiperda is considered to be polyphagous, this pest is closely associated with grasses (maize, wheat, oat) and has lower potential as a soybean or cotton feeder. Howerver, S. frugiperda food intake regulation appears to be triggered by a complex of different mechanisms. Thus, S. frugiperda can also damage soybean and cotton and adapt to them in the absence of preferred hosts

Biology and nutrition of Spodoptera frugiperda (Lepidoptera: Noctuidae) fed on different food sources

ABSTRACT: We studied Spodoptera frugiperda development using different food sources in the laboratory and field. Newly hatched larvae were fed soybean, cotton, maize, wheat, and oat leaves. An artificial diet was used as the control. Duration of pre-pupal, pupal, and larva-adult period, pupal weight, sex ratio, survival, larva feeding preferences, oviposition preferences, and nutritional quality of different hosts were evaluated. Insects fed on wheat showed the shortest larva-adult period. The insects fed on cotton and soybean had longer larval development cycles and pupae of lower weight. Feeding preference was evident for third instar larvae and did not differ between wheat, oat, maize, and soybean, which were the preferred hosts. Moths oviposited to a greater extent on the upper canopy of wheat than that of other plants in both the no-choice and free-choice tests. Treatments influenced insect growth, food consumption, and digestion when nutritional variables were analyzed. Thus, grasses were better hosts for S. frugiperda development. Cotton was the least preferred food, followed by soybean. The present study can improve our understanding of S. frugiperda in these different crops and help in developing management strategies. Even though S. frugiperda is considered to be polyphagous, this pest is closely associated with grasses (maize, wheat, oat) and has lower potential as a soybean or cotton feeder. Howerver, S. frugiperda food intake regulation appears to be triggered by a complex of different mechanisms. Thus, S. frugiperda can also damage soybean and cotton and adapt to them in the absence of preferred hosts