Spatial and temporal distribution of cotton squares and small cotton bolls fallen on ground after damage by boll weevil and the efficiency of the equipment used to collect them

Abstract

Spatial and temporal distribution of cotton squares and small cotton bolls fallen on ground after damage by boll weevil... Ciência Rural, v.47, n.7, 2017. INTRODUCTIONCotton crop (Gossypium hirsutum L.) is attacked by a wide variety of phytophagous arthropods with potential to cause serious damage to culture (RIBEIRO et al., 2015). Among these, the boll weevil Anthonomus grandis Boheman (Coleoptera: Curculionidae) is a key pest of cotton in the new world (SALVADOR et al., 2014). This insect has spread throughout the cotton-producing regions of Brazil, which has led to a severe increase in the cost of production due to economic losses arising from the insect feeding behavior and oviposition on the cotton squares and bolls (SILVA & RAMALHO, 2013).The boll weevil is mainly controlled by application of chemical insecticide during the flowering period to protect cotton squares (SILVA & RAMALHO, 2013;SILVA & SILVA, 2015). Important alternatives to cotton insecticides include various types of cultural control tactics, as suggested elsewhere (GREENBERG et al., 2010).The collection of cotton squares and cotton bolls damaged by weevil and fallen on the ground is one such tactic that promises to be of great value to RURAL ENGINEERING

Infestation of Anthonomus grandis grandis (Coleoptera: Curculionidae) contributes to forming shelter structures in cotton plants

“…The relationship between boll weevil population density and damaged cotton reproductive structures (da Silva et al., 2017; Greenberg et al., 2003; Grigolli et al., 2017) is enhanced by the overlapping of generations synchronized with the phenological development of the cotton plants (da Silva et al., 2017; Showler et al., 2005). In this study, the number of green bolls was reduced in plants infested with the boll weevil throughout the evaluations, more severely in treatments with greater density of the insect.…”

“…The number of feeding and oviposition punctures per dry boll, in this study, was greater in treatments with a higher density of weevils. Boll weevil feeding and oviposition behaviour depend on population density and food availability (da Silva et al, 2017;Nussenbaum et al, 2018;Showler et al, 2005), however, only squares and green apples have been studied so far. The boll weevil, at low population density and proper food availability, makes a single oviposition puncture per square and prefers to feed on this structure (Nussenbaum et al, 2018;Showler, 2004Showler, , 2007.…”

Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae) induces the formation of shelter structures in cotton plants

“…The greater number of holes per dry boll in the six and eight pair treatments is the result of the feeding and oviposition behavior of the boll weevil, which depends on population density and food availability (Showler et al 2005, Silva et al 2017, Nussenbaum et al 2018. In low population density and with ample food availability, the boll weevil makes a single oviposition hole per ower bud and prefers to feed on this structure (Showler 2004, Showler 2007, Nussenbaum et al 2018.…”

“…Variability in the number of ower buds and bolls between treatments indicates a relationship between the weevil population density and damage to cotton reproductive structures (Greenberg et al 2003, Grigolli et al 2017, Silva et al 2017, which is enhanced by the overlapping of generations synchronized with the phenological development of the cotton plant (Showler et al 2005, Silva et al 2017. Injuries caused by weevils lead to abscission of ower buds and small green apples.…”

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

“…The cotton boll weevil (CBW) causes losses, such as high abscission of cotton squares (bud flowers) and abnormal opening of its capsules in all Brazilian cotton-producing regions due to its eating habits and oviposition in the plant reproductive structures (squares and small bolls) (Silva et al, , 2017. Cotton squares abscission occurs especially in those formed between 40 and 60 days old, depending on the cotton variety (Ribeiro et al, 2010;Pimenta et al, 2016).…”