Outbreaks of Chrysodeixis includens (Walker) (Lepidoptera: Noctuidae) in common bean and castor bean in São Paulo State, Brazil

Abstract

Since 2009, increasing populations of Chrysodeixis includens (Walker) (Lepidoptera: Noctuidae) have been observed in cultivated common bean (Phaseolus vulgaris L.) and castor bean (Ricinus communis L.) at the Lageado Experimental Farm, belonging to the FCA/UNESP, Botucatu, São Paulo State, Brazil. Defoliations around 80% and 50% were observed in the common bean cv. Pérola and castor bean cv. IAC-2028, respectively. Samples of individuals (caterpillars and pupae) were collected in the field, and kept in laboratory until adult emergence aiming to confirm the species. These are new observations for common bean in São Paulo State and, in the case of castor bean, unpublished in Brazil. It suggests that C. includens has adapted to attack other agricultural crops, demanding attention of common bean and castor bean producers.Key words: herbivory, alternative hosts, soybean looper.Surtos populacionais de Chrysodeixis includens (Walker) (Lepidoptera: Noctuidae) em feijoeiro e mamoneira no Estado de São Paulo, Brasil ResumoDesde 2009, populações crescentes de Chrysodeixis includens (Walker) (Lepidoptera: Noctuidae) vêm sendo observadas em lavouras de feijoeiro comum (Phaseolus vulgaris L.) e mamoneira (Ricinus communis L.), na Fazenda Experimental Lageado, pertencente à FCA/UNESP, Campus de Botucatu, Estado de São Paulo, Brasil. Desfolhas ao redor de 80% e 50% foram constatadas em feijoeiro Pérola e em mamoneira IAC-2028, respectivamente. Amostras de indivíduos (lagartas e pupas) foram coletadas a campo e mantidas em laboratório até a emergência dos adultos para confirmação da espécie. Essas observações em feijoeiro são inéditas para o estado de São Paulo e, no caso da mamoneira, inéditas no Brasil, sugerindo que o inseto vem se adaptando e atacando outras culturas de interesse agrícola, exigindo maior atenção por parte dos produtores de feijão e mamona.Palavras-chave: herbivoria, hospedeiros alternativos, lagarta falsa-medideira.

Natural resistance of soybean cultivars to the soybean looper larva Chrysodeixis includens (Lepidoptera: Noctuidae)

“…Specht et al (2016) assessed the reproduction potential of S. eridania in soybean and noticed that the number of copulated females was not affected by the size of pupae; however, differences were observed while analyzing egg fertility and adult longevity. Souza et al (2014) studied ten soybean cultivars and found that the duration and survival rate of the larval stage, the duration of the pupal stage, cycle duration, and larval weight were the main biological variables that contributed to the evaluation of the antibiosis effect on S. eridania. In the present study, the same evaluated variables also played an important role in determining the effect of soybean antibiosis on C. includens.…”

“…According to Souza et al (2014), the PI 227687 and PI 227682 soybean cultivars expressed high antibiosis effects on S. eridania, and IAC 100 and DM 339 were found to provide moderate resistance, extending the life cycle of this insect. Boiça Júnior et al (2015) also observed that the Dowling cultivar extended the duration of the larval stage of S. cosmioides, which was considered as an indicative of low-quality food.…”

“…Considering that cultivars can slow insect development, affecting population dynamics and pest control methods, further work should be conducted on other plant resistance variables, such as oviposition antixenosis, in order to use the obtained information to recommend new cultivars or to improve soybean breeding programs (Souza et al, 2014;Boiça Júnior et al, 2015).…”

“…to its: occurrence in all states of the country; high polyphagia, with 175 species of host plants; and resistance to control measures, such as the application of insecticides, which can be explained by the habit of the species taking shelter in the middle and lower thirds of the plant (Hoffmann-Campo et al, 2012;Baldin et al, 2014;Specht et al, 2015). The incorrect use of insecticides and fungicides on soybean has also been identified as a factor that has contributed to the increase of this insect population, particularly by contributing to a high mortality of biological control agents (Sosa-Gómez et al, 2010).…”

Sublethal Doses of Insecticides Affect the Fecundity and Fertility of the <i>Chrysodeixis includens</i>?

“…The use of chemicals and transgenic plants is a major control measure employed in the management of C. includens [1] [2]. Among the commonly used insecticides, there is an obstacle due to two aspects: resistant, and the lack of knowledge about the lethal and sublethal effects of insecticides on the pest [6] [7].…”