The effect of planting different species of border plants on the population density of thrips (Thrips tabaci Lind), and syrphid predators (Toxomerus spp.), population density were evaluated at EPAGRI, Santa Catarina State, Brazil. The research was carried out from August to December 1998. The treatments were onion monoculture; onion intercropped with buck wheat (Fagopyrum esculentum Moench) (Poligonaceae); onion intercropped with fodder radish (Raphanus sativus L. var. oleiferus Metzg.); onion intercropped with carrots (Daucus carota L.) Nantes and Brasília cultivars; onion intercropped with maize (Zea mays L.); onion intercropped with Eruca sativa and weed. The onion thrips and syrphid predators population density were similar in onion monoculture and policulture. The yields were similar in onion monoculture and policulture, suggesting the possibility to intercrop onion without losses.
Allium cepa; Thrips tabaci; insect; vegetal diversity; policulture; agroecology