Potentiality of Chinese cabbage (Brassica rapa subsp pekinensis) as a trap crop for diamondback moth (Plutella xylostella) management in cabbage

摘要

Laboratory, net house and field experiments were conducted at Varanasi during 2003-07 to study a few biological parameters and ovipositional preference of diamondback moth (Plutella xylostella L.) among 6 crucifers for searching an effective and alternative host other than mustard (Brassica juncea) with potential of being used as trap crop for management of diamondback moth in cabbage (Brassica oleracea var. capitata). Although the larval weight was significantly more in Chinese cabbage, the larval period of diamondback moth was significantly more prolonged on Chinese cabbage (10.44 days) than other cruciferous hosts. In laboratory experiments, both no-choice and free-choice tests consistently showed almost two-fold preference by diamondback moth for oviposition on Chinese cabbage over cabbage. In the net house, under free-choice situation also the egg laying preference on Chinese cabbage was significantly higher (377 eggs/plant) than mustard (148.50 eggs/plant) and cabbage (114.50 eggs/plant). The larval population at two intervals after release (10 and 15 days) of adults among the test crucifers inside the field screen cage also confirmed maximum attractiveness of Chinese cabbage over mustard and cabbage for egg laying and larval survival. Considering these facts and better agronomic feasibility of Chinese cabbage as an ideal alternative to mustard for use as a trap crop in the management of diamondback moth of cabbage.