Diversity of the arthropod fauna in organically grown garlic intercropped with fodder radish

Abstract

The cultivation of garlic faces several problems, which include pest attack, and the diversification of habitat through intercropping with attractive plants comes up as a method to pest management. The objective of this research was to verify the effect of the association of garlic with fodder radish on richness, abundance and diversity of arthropods under organic production system in Lavras, MG, Brazil. The treatments were composed of garlic in monoculture and garlic in association with fodder radish, in plots of 40 garlic plants, intercropped or not with two lines of fodder radish. Weekly, 25 samples were collected for a period of 10 weeks (n=250). Species accumulation curves, species richness, abundance, and diversity index were determined, and T or Mann-Whitney tests were used for analysis. The 250 samples collected were sufficient to register the majority of species present in garlic. Richness and abundance were higher in diversified garlic whereas diversity was higher in monoculture. Diversified system increased the overall richness of phytophagous species and parasitoids. The abundance of T. tabaci decreased, while increased the presence of A. fabae, demonstrating that the association was potentially beneficent to the culture. The possible reasons for these results are discussed, and future works should focus in the ecological mechanisms involved in crop diversification of organic garlic.