Toxicidade de agroquímicos usados na cultura do milho na Espanha, sem e com chuva, para Chrysoperla carnea (Stephens, 1836) (Neuroptera: Chrysopidae) em laboratório e casa de vegetação

Abstract

This study aimed to evaluate the effects of the products deltamethrin (DECIS®1.5% EW, Pyrethroid, 12.45 mg a.i./L), chlorpyrifos (CHAS® 48% EC, Organophosphate, 960 mg a.i./L), λ-cyhalothrin (KARATE® 10% WG, Pyrethroid, 20 mg a.i./L), abamectin (APACHE®1.8% EC, Avermectin, 18 mg a.i./L), hexythiazox (PERFIL®10% WP, Carboxamide, 75 mg a.i./L) and pendimethalin (PENDALIN® 33 % EC, Dinitroaniline, 1.980 mg a.i./L), on third instar larvae and adults of Chrysoperla carnea (Stephens).This study consisted of two experiments. The first experiment, third instar larvae and adults of C. Carnea were exposed to glass plates treated with the products through application by Potter tower. The effects of the products were evaluated the mortality, pupation, emergence, fecundity, viability and sex rate of the insects. On the second experiment, maize plants were treated through pulverization with the insecticides deltametrin and chlorpyrifos in a greenhouse and 24 hours after application, some of these plants were submitted to 2mm of artificial rain. After 1, 4, 7, 14, 21 and 32 days the application of the products, leaves of these plants were detached and put in contact with the third instar larvae of C. carnea to evaluate the residual effects of these products on the mortality, pupation, emergence, fecundity, viability and sex rate of the insects. On the first experiment, it was observed that chlorpyrifos and daltametrin were respectively harmful and moderately harmful to third instar larvae and harmful to adults of C. carnea. The insecticide λ-cihalotrin was slightly harmful and harmful to larvae and adults of C. carnea respectively; abamectin e hexythiazox were slightly harmful to larvae and adults of C. carnea, while pendimethalin was harmless to the third instar larvae. On the second experiment, it was verified that the artificial rain affected the residual power of the insecticide chlorpyrifos, making it less toxic, therefore, it is recommended the release of third instar larvae of C. carnea only after 14 days of its application and after 32 days on the absence of rain. Deltametrin presented low residual power to third instar larvae of C. carnea on both, presence and absence of artificial rain and was classified as short live and can be recommended in integrated pest management programs on maize crop in Spain, seeking the preservation of this predator on this phase of development.