Assessing the potential of trap cropping in the management of different insect taxa on white cabbage

Abstract

This study set out to explore the influence of trap crops designated for the management of Crocidolomia pavonana (Fab.) on two other frequent pests of cabbage: diamondback moth [Plutella xylostella (L.) and cabbage aphid (Brevicoryne brassicae (L.)]. The three pests were offered six hosts in the genus Brassica: kale (B). oleracea var. acephala), cauliflower (B. oleracea var. botrytis), broccoli (B. oleracea var. italica), Chinese cabbage (B. campestris L. ssp. pekinensis), Indian mustard (B. juncea (L.) Czern.), and white cabbage (B). oleracea var. capitata) in multiple (where all the six were offered at the same time) and two-crop trials (where each of the different hosts was paired with cabbage, including a control of cabbage in monoculture) in field trials. Oviposition was considered as a measure of preference for C. pavonana and P. xylostella while colonization and reproduction were measures of preference for B. brassicae. The treatments were arranged in a complete randomized block design with four blocks. The experiment was carried out in the field in 2007 and 2008. The results indicated that C. pavonana oviposition on cabbage was consistently lowered in trap crop treatments when compared with monoculture. The results for P. xylostella and B. brassicae were not as consistent and there was a great deal of variation. It was clear, however, that trap cropping for the control of C. pavonana would not worsen pest problems with the diamondback moth or the cabbage aphid.