MANEJO CONVENCIONAL PARA Liriomyza huidobrensis (DIPTERA: AGROMYZIDAE), COM DIVERSIDADE DE GRUPOS QUÍMICOS E IMPACTO SOBRE INIMIGOS NATURAIS, EM PLANTAS DE Solanum tuberosum

Abstract

Liriomyza spp. (Diptera: Agromyzidae) are cosmopolitan, generalist pests, with great genetic variability, atypical population explosions and resistance to insecticides already reported. Conventional management is still widely used against leaf miner larvae in potato plants. However, studies that point to promising synthetic chemical insecticides, with low toxicity, can help in good practices of use, in field conditions. And that includes managing the evolution of resistance to insecticides, with rotation of active ingredients under different MoA. The aim of the study was to fill existing gaps in knowledge about the management of Liriomyza huidobrensis (Diptera: Agromyzidae) adults and larvae, their spatial distribution in potato plants and the selectivity of insecticides to natural enemies associated with larvae. The treatments were six synthetic insecticides: (T1) spinetoram, (T2) chlorfenapyr, (T3) thiamethoxam+, so named because is a factory mixture involving abamectin, (T4) cyantraniliprole+, also containing abamectin in the formulation, (T5) cyantraniliprole, (T6) indoxacarb and, finally, an absolute control (T7), with only water. Yellow sticky traps were used to sample adults, but the number of mines was visually recorded for the upper, middle and lower thirds of the potato plants. Adult flies of Liriomyza huidobrensis were collected in greater numbers than mines. The insecticides evaluated, regardless of which, showed higher means of suppression for adult flies than for mines. Spinetoram (T1) and chlorfenapyr (T2) significantly reduced the number of mines plant-1. The amount of mines plant-1 showed an increasing behavior over time, regardless of the treatments. Liriomyza huidobrensis larvae were sampled in greater numbers in the upper and middle thirds than in the lower. In the upper and middle thirds, there was a greater oscillation in the number of mines plant-1 sampled, over time, when the insecticides were applied. The absolute number of parasitoids sampled was 2.21 times higher compared to the predator Chrysoperla externa. However, the amount of C. externa adults collected showed less oscillation, over time, under the effect of insecticides. Additional considerations about our results are discussed with an appeal to the philosophy of Integrated Pest Management in potato plants.