The behavior of Aphis gossypii and Aphis craccivora (Hemiptera: Aphididae) and of their predator Cycloneda sanguinea (Coleoptera: Coccinellidae) in cotton-cowpea intercropping systems.

Francisco S Fernandes,José B Malaquias,Bárbara D.B Santos,Wesley A.C Godoy,Francisco S Ramalho

doi:10.1590/0001-3765201820160212

Abstract

The intercropping is an important cultural practice commonly used in pest management. It is based on the principle that increased plant diversity in the agro-ecosystem can lead to reductions of pest populations in the crop. The current study aimed to assess the impact the colored fiber cotton-cowpea intercropped systems on Aphis gossypii and Aphis craccivora and on their predator Cycloneda sanguinea and the losses and the dispersion behavior of these aphids and their predator in these cropping systems. The experiment had a randomized block experimental design with two bioassays and four treatments. The number of apterous and alate aphids (A. gossypii) per cotton plant was 1.46 and 1.73 or 1.97 and 2.19 times highest in the solid cotton system than that found in the cotton-cowpea intercropped systems (S1) and (S2), respectively. On the other hand, the cotton-cowpea intercropped systems (S1 and S2) reduced, respectively, in 43% and 31% the number of apterousA. gossypiiper cotton plant compared to the control. Implementing cotton-cowpea intercropped system in the S1 scheme reduced A. gossypii infestation, favored the multiplication of C. sanguinea, and allowed obtaining heavier open bolls.

Highlights

Cotton (Gossypium hirsutum L.) cultivars with naturally colored fibers have worldwide demand in the textile industry and have added value to the crop for small farmers (Fernandes et al 2012a, Ramalho et al 2012a)
The number of aphids per cotton plant quantified in the cotton-cowpea intercropped cropping system (S3) (Fig. 1) (656 apterous and 88 alates) (Fig. 2) was similar to that of the solid cotton system (S4) (Fig. 1) (798 apterous and 136 alates) (Fig. 2)
The intercropping of different plant species is an important cultural practice commonly used in pest management; it is based on the principle that the reduction of insect pest populations in the crop may occur due to increased agro-ecosystem diversity (Risch 2005)

Summary

Introduction

Cotton (Gossypium hirsutum L.) cultivars with naturally colored fibers have worldwide demand in the textile industry and have added value to the crop for small farmers (Fernandes et al 2012a, Ramalho et al 2012a). Aphis gossypii damages cotton plants during both vegetative and reproductive stages (Ramalho et al 2012a, Fernandes et al 2012b) and many plant species including eggplants and okra (Leite et al 2006, 2007). Infestation in vegetative stages turn leaves shriveled, whereas infestation in reproductive stages, especially at fruit opening, fouls and reduces fiber quality (Almeida 2001). Severe attacks by A. gossypii may reduce leaf area and biomass, besides branching and plant height, harming the crop and results in economic losses (Sarwar et al 2014)

Methods

Results

Conclusion