Seletividade fisiológica de inseticidas usados na cultura do milho para o predador Doru luteipes (Scudder) (Dermaptera: Forficulidae)

Abstract

The earwig Doru luteipes (Sccuder) (Dermaptera: Forficulidae) is able to prey on eggs and small caterpillars of some species of lepidoptera that can feed on corn plants and therefore must be preserved. The objective of this work was to evaluate the selectivity of the compounds flubendiamide, imidacloprid + betaciflutrina, metaflumizone and Baculovirus Spodoptera frugiperda, in their highest doses in the control of pests in corn fields, for D. luteipes in its immature and adult stages. Imidacloprid + betaciflutrin when applied on corn leaf surface caused total nymph mortality in 72 hours and when ingested through treated S. frugiperda eggs presented total mortality in 6 days. This compound also caused a reduction in insect predation. Metaflumizone applied to the surface of maize leaves caused total mortality of nymphs in 13 days and when ingested it caused high mortality, but did not reach 100% in the period of 15 days. It also reduced the predation of the nymphs, but did not decrease the tibia size, weight, sex ratio or longevity of adults from these treated nymphs. Flubendiamide and Baculovirus Spodoptera frugiperda did not reduce any biological parameters evaluated. In adult bioassays, imidacloprid + betaciflutrin reduced adult survival, causing total mortality in 12 days, but did not reach 100% when adults were exposed through a contaminated surface. It also led to a significant reduction in adult predation and reduced the walking behavior of adults cantaminaminated by ingestion. Metaflumizone reduced adult survival, the reduction being more pronounced when exposed to contact with a contaminated surface, and also decreased both predation and walking. Due to the low toxicity conferred by flubendiamide and Baculovirus Spodoptera frugiperda to D. luteipes in their immature and adult stages, these insecticides should be prioritized in integrated pest management programs aimed at the preservation of this species of predator in corn crops.