Chrysodeixis includens EM PLANTAS DE BATATA: DISTRIBUIÇÃO TEMPORAL, CONTROLE EM CAMPO, DANO FOLIAR E IMPACTO NA PRODUÇÃO DE TUBÉRCULOS

Abstract

Potato is one of the most important sources of energy for the population worldwide. However, plants of this Solanaceae have great hostability to herbivores, such as defoliating caterpillars. Chrysodeixis includens (Lepidoptera: Noctuidae) has been benefited by green bridges between soybean-potato in the Cerrado biome. Therefore, a serious threat to agricultural production and food security. Cases of insecticide resistance, for this polyphagous insect, are been recorded in Brazil. Field research that can generate information for use in Integrated Pest Management programs against C. includens in potatoes plants must be urgently explored. We investigated the temporal distribution in C. includens caterpillars, on potato plants (cv. Ágata). We compared the control efficiency (CE%) of six moderately toxic insecticides (indoxacarb, cyantraniliprole, chlorfenapyr, thiamethoxam+abamectin, cyantraniliprole+abamectin and spinetoram). As well as the microbiological fungus (Beauveria bassiana) and the vírus (ChinNPV+HearNPV) against caterpillars. Defoliation damage (%) caused by the caterpillars and, finally, components of tuber production were quantified. Chrysodeixis includens caterpillars ocurred at 40 DAP (days after planting) until 89 DAP. Temporal distribution of caterpillars was modeled by 1st order polynomial regression equations. But with cyantraniliprole, fungus and absolute control showing 2nd order responses. The CE% also varied between treatments, ranging from 32.45% to 93.89%. The population fluctuation of caterpillars was dependent on their size, time and treatments. Caterpillars with body length between 4 and 6 mm were more abundant. Defoliation damage occurred mostly in the lower and middle thirds, than in the upper ones. The spinetoram treatment better contained caterpillar defoliation with only 18.08%, at 28 DaAP (days after aplication). All potato production components were superior with all insecticides, as well as with vírus application. But inferior when the fungus was used. Our findings provide valuable information to predict the population dynamics of C. includens in potato plants. We present efficient ways of caterpillars control, with an environmentally friendly approach, resulting in lower values of defoliation and without risk of loss in the quality and yield of tubers. The clear differences observed between treatments, in addition to the signs of adaptability that C. includens presented, in potato plants, are discussed in detail.