DISTRIBUIÇÃO ESPACIAL E CARACTERIZAÇÃO DE POSTURAS DE Spodoptera eridania, EM PLANTAS DE BATATA, MEDIADAS PELO CLORFENAPIR

Abstract

Spodoptera eridania (Cramer) (Lepidoptera: Noctuidae) is part of the caterpillar species occurring in soybean, Glycine max (L.) (Fabaceae). With losses as a defoliator in potato plants, Solanum tuberosum L. (Solanaceae), cultivated in the Brazilian Cerrado biome. Insecticides can force behavioral changes in agricultural pests. However, S. eridania adaptability mediated by insecticides, focusing on the oviposition of adult females, in potato plants, is still little explored. This information may help to understand how these polyphagous insects have adapted to crops comprised of green bridges, such as soybean-potato. The objective was to evaluate S. eridania spatial distribution and clutch characterization, in potato plants, with and without spraying with the insecticide chlorfenapyr. Clutch collection occurred from the 7th to 91st day after planting (DAP) of potato, allowing inferences about its distribution throughout the plant cycle. Clutch spatial distribution, within the plant, was quantified in Ágata cultivar, in areas treated or not with the insecticide. And depending on the lower, middle, or upper thirds. Clutches were also recorded as to which leaf face were collected (adaxial or abaxial). And, finally, the presence of scales, covering the eggs in the clutches, was recorded on a grade comprising high density, low or no scales. From the 28th DAP, the first S. eridania clutches were collected, until the 63rd DAP, totaling 322 collections, regardless of the treatments. 90% of clutches were collected in the upper and middle thirds, with a minority in the lower (10%). Spodoptera eridania females preferred to lay eggs in the middle third of the sprayed plants. While, without spraying, the preference occurred in the upper third of potato plants. 93.00 ± 1.20% of the eggs were deposited on the abaxial surface with chlorfenapyr, but with no significant difference in the plots without insecticide. The percentage of S. eridania eggs with high density of scales, low or without scales did not vary significantly between treatments. However, most clutches collected, regardless of treatments, contained a high density of scales covering the eggs. These results are discussed in terms of better understanding the relationship between S. eridania as an emerging pest in potato plants and how this adaptation has been favored using insecticides.