Chemical control is the main method for controlling the tomato leafminer, Tuta absoluta (MEYRICK, 1917) (Lepidoptera: Gelechiidae). Reported techniques for the evaluation of insecticide toxicity to the tomato leafminer are not in agreement with field conditions and do not allow us to verify whether doses used in the field are efficient for control. Thus, the objective of this work was to develop a bioassay methodology to study the toxicity of insecticide formulations to T. absoluta that represent field conditions for fast-acting insecticides (neurotoxics and inhibitors of respiration) and slow-acting insecticides (Bacillus thuringiensis and insect growth regulators). The leaf-dip method was the most efficient method for toxicity studies of insecticides formulations to T. absoluta. We verified that bioassays with fast-acting insecticides should be performed with glass Petri dishes containing one tomato foliole from the 4 th leaf from the plant apex infested with 10 larvae of 3 rd instar and these bioassays can last 48 hours. Conversely, bioassays with slow-acting insecticides should be performed with two-liter transparent PET bottles containing the 4 th leaf from the plant apex, with their petioles immersed in a glass bottle containing 120 mL of water, and this leaf should be infested with 10 larvae of 2 nd instar and this bioassays can last seven days.Index terms: Susceptibility, tomato leafminer, chemical control, bioassay standardization, resistance survey. RESUMOO principal método utilizado no controle da traça-do-tomateiro Tuta absoluta (MEYRICK, 1917) (Lepidoptera: Gelechiidae) é a aplicação de inseticidas. As técnicas atuais de avaliação da toxicidade de inseticidas sobre essa praga não simulam a situação de campo e não possibilitam a verificação se as doses usadas no campo são eficientes no seu controle. Assim, neste trabalho, objetivouse desenvolver uma metodologia que represente as condições de campo para inseticidas de ação rápida (neurotóxicos e inibidores respiratórios) e de ação lenta (Bacillus thuringiensis e reguladores de crescimento. A metodologia mais eficiente para estudos de toxicidade de formulações comerciais a T. absoluta foi a imersão de folhas em calda inseticida. Para os bioensaios de inseticidas de ação rápida, sugere-se que estes sejam realizados em placas de Petri, contendo folíolos de tomate da 4ª folha a partir do ápice da planta, infestados com 10 larvas de 3º ínstar e eles podem durar 48 horas. Quanto aos bioensaios de toxicidade de inseticidas de ação lenta, sugere-se que sejam realizados em garrafas PET transparentes, de dois litros, contendo a 4ª folha de tomate a partir do ápice da planta infestada com 10 larvas de 2º ínstar e seu pecíolo inserido em vidro de 120 mL contendo água. Nesse caso, o bioensaio pode durar sete dias sem prejuízo na eficiência.Termos para indexação: Suscetibilidade, traça-do-tomateiro, controle químico, padronização de bioensaio, levantamento de resistência.

All three economic injury levels determined and the sequential sampling plans developed in this study are suitable for incorporation into integrated management programs for common bean pests because they can be used by farmers operating at various technological levels to make adequate and rapid decisions. © 2017 Society of Chemical Industry.

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Brevicoryne brassicae (L), Lipaphis erysimi (Kalt) and Myzus persicae (Sultzer) (Homoptera: Aphididae) form the aphid complex that causes great losses in Brassicaceae in tropical and subtropical regions. Knowledge of their population dynamics is important for the development of integrated pest management programmes. This study aimed to investigate the effects of cabbage phenology, climatic factors and natural enemies populations on the dynamics of these organisms, and the factors regulating their predators’ occurrence. The densities of aphids and their natural enemies and the climate were monitored for two years in 16 cabbage crops. The highest densities of the aphids occurred during periods of relative humidity (RH) drop, a condition that affects them positively. Regarding the predators, the factors affecting their abundance varied but RH was positively related to most of them. This study provides relevant insights into the factors that regulate the aphids in cabbage and for the decision‐making process of control of these severe pests.

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