Assessment of a cabbage/pak choï crop association to manage aphid and parasitoid populations on cabbage crops in Senegal

Abstract

In Senegal, vegetable production is an important area within the agricultural sector and contributes to improve the local diet. Damage caused by aphids in particular puts heavy pressure on vegetables production. Crop associations play an important role in controlling insect pests in some countries. The aims of this study include investigations into the diversity of aphid and parasitoid populations, and an  evaluation of the effects of crop associations between cabbage and pak choï. The experimental design used is a randomized block with four treatments and two controls, that is cabbage and pak choï , and two crop associations, that is pak choïn between cabbage rows, and pak choï around cabbage beds. Two aphid species,  Myzus persicae, and Lipaphis pseudobrassicae are identified. The Braconidae Diaeretiella rapae (Mac Intosh) (Hymenoptera: Braconidae) is the only parasitoid met during the study. Myzus persicae (Sulzer) is more abundant than Lipaphis pseudobrassicae (Davis). Myzus persicae and L. pseudobrassicae were not  controlled by the cabbage / pak choï associations. Aphids populations decreased during the heading phase of the cabbage. This preliminary study contributes to a better understanding of the potential use of crop associations to manage cabbage aphid populations in Senegal.

Keywords: Crop associations, Myzus persicae, Lipaphis pseudobrassicae,  Diaeretiella rapae, Brassicaceae, Senegal.