Effects of wheat/oilseed rape and wheat/pea associations on the diversity of aphids and aphidophagous beneficials

This study was conducted in the Shandong province (China) to better characterize the effect of wheat/oilseed rape and wheat/pea associations on the populations of aphids and aphidophagous beneficials. At specific times of the season, the observations on wheat tillers confirm the resource concentration and the enemy hypotheses. In fact, aphids were more abundant in the pure stand of wheat, while more ladybirds were observed in the associations. As for the trapping of aphidophagous beneficials, the parasitoid species Aphidius gifuensis (Ashmead) was prevalent. Among predators, Propylea japonica (Thunberg) and Harmonia axyridis (Pallas) were the most abundant species. Few lacewings and hoverflies were trapped. This study shows a beneficial effect of crop associations on the control of aphid populations.