Cover crop intercropping increases biological control in coffee crops

Abstract

Losses in coffee crops due to the pest attack harm up to 50% of production. In an attempt to control the progress of these herbivores, chemical inputs are used on crops, but with limited success and negative impact on biodiversity and on human health. We investigated in a field experiment whether cover crop intercropping with coffee would reduce coffee pest population by increasing natural enemy abundance. The cover crops Crotalaria juncea and Fagopyrum esculentum were selected based on agronomic traits and on the provision of food resources to natural enemies. They were tested in plots in a single cultivation and in mix combination intercropped with coffee. The control treatment was represented by coffee monoculture with bare soil. Predation rate of a key coffee pest, the coffee leaf miner Leucoptera coffeella, was higher in intercropped plots than in the monoculture. Increased parasitism rate of L. coffeella was found in plots intercropped with F. esculentum. However, during the experimental period, L. coffeella abundance was not affected by the cover crops. Phytophagous mites from Tetranychidae family were less abundant when coffee was intercropped with C. juncea. Their predators, Phytoseiidae mites, were more abundant on coffee intercropped with C. juncea and C. juncea plus F. esculentum. Diversification of coffee crops by intercropping with cover crops promotes biological control of phytophagous mites and shows potential for coffee leaf miner control. These results, together with the improvement of chemical, physical and biological characteristics of the soil and reduced weed competition, make cover crop intercropping a suitable strategy for coffee cultivation.