Temporal variation and spatial distribution of the pest insect Edessa meditabunda in cotton (Gossypium hirsutum) as an alternative host plant

Rafael Azevedo Da Silva,Matheus Dalla Cort Pereira,Paulo Eduardo Degrande,Ellen Patrícia De Souza

doi:10.1590/1806-9665-rbent-2021-0029

Abstract

Cotton is an alternative host for Edessa meditabunda (Hemiptera: Pentatomidae), especially after the soybean harvest in surrounding areas, when large numbers of insects invade cotton fields and damage reproductive structures such as flowers and developing bolls. However, no studies on its occurrence and spatial distribution have been conducted in cotton. Therefore, this study was aimed to assess the temporal variation and spatial distribution of E. meditabunda in the alternative host plant, Gossypium hirsutum. The study was carried out in an area of 1.1 ha planted with cotton that was divided in 64 plots of 169 m2 each, where entire cotton plants were examined weekly and E. meditabunda nymphs and adults were counted. Dispersion rates and theoretical frequency distributions were calculated and analyzed with significance level at 5%. Assessments were carried out from seedling emergence until the appearance of bolls, but E. meditabunda was present only during the reproductive stage of cotton plants. This study detected the dispersal of this stink bug from late-cycle soybean fields to cotton, indicating cotton’s potential as an alternative host plant, providing shelter and food. Based on aggregation indices, the spatial distribution of nymphs and adults in cotton was aggregated at the beginning of the infestation, but tended toward randomness as bolls reached maturity. The occurrence of E. meditabunda in cotton was best described by the Poisson distribution with significance level at 5%.

Highlights

The stink bug Edessa meditabunda (Fabricius, 1794) (Hemiptera: Pentatomidae) is a Neotropical insect pest associated with many species of Solanaceae and Fabaceae, as well as cotton, eggplant, tobacco, sunflower, papaya, and grapes
Assessments were carried out from seedling emergence until the first appearance of bolls, but the occurrence of E. meditabunda was observed only during the reproductive stage of cotton, comprising the interval between 55 and 91 Days After the Emergence (DAE), with higher occurrence when the first flowers appeared at 70 DAE and a decrease in subsequent evaluations (77, 84, and 91 DAE), and disappearance after 91 DAE
At 55 and 70 DAE, nymphs, adults, and the total population of E. meditabunda had an aggregated distribution based on the variance-to-mean ratio and Morisita Index, while a random pattern was observed in the other evaluations

Summary

Introduction

The stink bug Edessa meditabunda (Fabricius, 1794) (Hemiptera: Pentatomidae) is a Neotropical insect pest associated with many species of Solanaceae and Fabaceae, as well as cotton, eggplant, tobacco, sunflower, papaya, and grapes. Phytophagous stink bugs of the Pentatomidae family have been considered occasional pests and of secondary importance in cotton in Brazil in the last few years. They are being frequently reported in significant numbers in Brazilian cotton-growing areas (Soria et al, 2009). This can be explained by the fact that when soybean is harvested and cotton fields are in proximity, the latter serves as shelter and food source, providing the conditions to support stink bugs until their preferred host plant is available (Azambuja et al, 2015). The management of stink bugs in cotton agroecosystems is a major concern in several countries in the Americas (Sosa-Gómez et al, 2019)

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