Phytophagous insects in cotton crop residues during the fallow period in the state of Mato Grosso do Sul, Brazil

Abstract: The objective of this work was to analyze the faunistic composition of the insect pests that occur during the fallow period in cotton (Gossypium hirsutum) crop residues in the state of Mato Grosso do Sul, Brazil. The study sites were the municipalities of Alcinópolis, Chapadão do Sul, Costa Rica, Aral Moreira, Dourados, and Sidrolândia. A sampling design with two replicates per municipality was used. Each replicate comprised 100 random points, and each point corresponded to a cotton plant that was entirely inspected, to count the insect pests on it. The obtained fauna was analyzed and a rarefaction curve of the species was generated. During the evaluation period, a total of 23 species were recorded in the cotton crop residue, and the most frequent and abundant were Bemisia tabaci, Aphis gossypii, Frankliniella schultzei, and Anthonomus grandis. The caterpillars were predominantly found on the non-Bt cotton crops in Dourados, and Chapadão do Sul was the municipality that exhibited the greatest species diversity. Despite being mandatory, the destruction of cotton stalks during the fallow period was not able to completely eliminate the insect pests during the study period; among these insect pests, A. grandis stands out, a species that affects the dynamics of cotton pest control.