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.

Colonization and Spatial Distribution of Boll Weevil in Commercial Cotton Fields

“…The changes observed for boll weevil population such as early colonization of the fields and presence of weevils deep inside cotton fields before flowering stage are likely related to the maintenance of an active portion of boll weevil population off-season reported for Cerrado and Semiarid areas (Paula et al 2013, Grigolli et al 2015, Neves et al 2018, Silva et al 2018, with successful reproduction on cotton regrowth (Grigolli et al 2015, Silva et al 2018. The cultivation of herbicide-tolerant cotton varieties has hindered good control of both regrowth and spontaneous cotton plants inside soybean and corn fields, preceding cotton planting, or in the adjacencies of cotton fields.…”

“…Population control late season has a special impact (Showler & Robinson 2008), considering that weevils can survive the winter dry off-season conditions in the Cerrado and semiarid (Paula et al 2013, Grigolli et al 2015, Neves et al 2018, Silva et al 2018. Late season reproductive females lay their eggs on developing bolls, mostly not commercialized bolls from plant tops produced after physiological plant cutting (Neves et al 2010).…”

“…Thus, controlling boll weevil requires attention during the flowering-fruiting stages of cotton plants, which is when plants become susceptible to both adult feeding and reproduction, causing direct crop loss. Data from literature also report about plant colonization (Showler 2006, Spurgeon 2016) and maintenance in the field (Fernandes et al 2001, Grigolli et al 2015, Neves et al 2018, Silva et al 2018, but information is lacking about how commercial cotton fields are colonized by boll weevil as a function of the crop phenology and their bordering vegetation in the Brazilian Cerrado. The knowledge about the spatial distribution of the boll weevil occurrence might help control decisions such as delimiting the area to deploy the BWACT and areas to be treated with insecticides (i.e., field borders instead of spraying the whole field).…”

Mortality of the cotton boll weevil in drip and sprinkler irrigated cotton crops

“…Over 260 insect species feed on cotton plants throughout their phenological cycle (Allen et al, 2018) with 10% being pests (Ribeiro et al, 2015;Silva et al, 2018). The cotton boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), is a key pest, reducing cotton crop productivity by up to 60% .…”

Genotype plus genotype by-environment interaction biplot and genetic diversity analyses on multi-environment trials data of yield and technological traits of cotton cultivars

“…Pakistan, and Brazil (CONAB, 2018). In Brazil, the Midwest region is mainly responsible for producing cotton, corresponding to over 70% of the total cultivated area (SILVA et al, 2018).…”