Effect of Cosmos, Crotalaria, Foeniculum, and Canavalia species, single-cropped or mixes, on the community of predatory arthropods

Abstract

Some plants can attract natural enemy by offering resources such as alternative food and refuge. However, studies need to be conducted before agricultural landscape diversification is implement. Our objective was to determine the best floristic compositions of cosmos ( Cosmos sulphureus—Asteraceae), showy rattlepod ( Crotalaria spectabilis—Fabaceae), fennel ( Foeniculum vulgare—Apiaceae), and jack bean ( Canavalia ensiformis—Fabaceae) to attract and maintain predatory arthropods, and know the potential of these treatments for future use in diversifying agricultural systems. The experimental design consisted in seven treatments of four species in single-crop, intercrops in three densities called mix1, mix2, and mix3, and the control (weeds). For the arthropod families classified as very frequent and constant, population dynamics in intercropping treatments was plotted according to the plant phenology. We conclude that all plants cultivated in single-cropping and intercropping treatments showed high predator richness and can potentially be used to diversify cultivated areas. Sulfur cosmos as a single crop and three mixes attracts higher numbers and greater family richness. Spider families—Oxyopidae, Araneidae and Thomisidae—and insects—Chrysopidae and Coccinellidae are more frequents. The dynamics of the predator populations varied according to the mixes treatment.