Bioatividade do extrato aquoso de sementes de nim sobre Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae) em três formas de aplicação | Bioactivity of aqueous neem seeds extract on the Tuta absoluta (Meyrick, 1917) (Lepidoptera: Gelechiidae) in three ways of application

This work, aimed to study the translaminar, systemic and contact action of aqueous neem seeds extracts on the tomato leafminer Tuta absoluta (Meyrick). Three experiments with aqueous neem seeds extracts at concentrations of 0.5; 1.0; 5.0 and 10.0g/100 mL of water were conducted. These extracts were applied in the soil, in adaxial surface of the tomato plant foliole and directly over the insect. When the extracts were applied in the soil of pots containing tomato plants, the larval mortality rate was 48.3% to 100.0%, indicating that the extracts were absorbed and transferred inside the plant. There was also a larval mortality of 57.0% to 100.0% when the extracts were applied over the foliole adaxial surface, which shows the translaminar action. When the extracts were applied directly over larvae six days old, the larval mortality rate was 52.4% to 95.4%, which shows the action of contact of the extracts and its potential to control the tomato leafminer.

No presente trabalho, avaliaram-se as atividades translaminar, sistêmica e de contato do extrato aquoso de sementes de Azadirachta indica A. Juss. (nim) sobre a traça-do-tomateiro Tuta absoluta (Meyrick). Foram realizados três experimentos envolvendo extratos aquosos de sementes de nim em concentrações de 0,5; 1,0; 5,0 e 10,0 g por 100 mL de água. Esses extratos foram aplicados no solo, na superfície adaxial de folíolos de tomateiro e diretamente sobre as lagartas. Quando os extratos foram aplicados no solo, em vasos contendo plantas de tomate, houve mortalidade de 48,3 a 100,0% das lagartas, indicando que foram absorvidos e translocados na planta. Também ocorreu mortalidade larval de 57,0 a 100,0% quando os extratos foram aplicados na superfície adaxial do folíolo, evidenciando o efeito translaminar. Quando foi aplicado diretamente sobre lagartas com seis dias de idade, observou-se mortalidade de 52,4 a 95,4%, demonstrando a ação de contato do composto e seu potencial para controle da traça-do-tomateiro.