EFFECTS OF DROUGHT STRESSED COTTON ON BEET ARMYWORM OVIPOSITION PREFERENCE AND LARVAL GROWTH

摘要

The beet armyworm, Spodoptera exigua (Hübner), has been anecdotally reported to lay more eggs on drought stressed cotton plants than on non-stressed cotton plants. This study demonstrated that, using potted cotton plants grown in well watered conditions, and on water-deficit regimes of 1,500, 1,000, and 750 ml water/wk, beet armyworms deposited 3.3, 4.6, and 2.3 times more (P < 0.05) eggs on plants in the three respective water deficit regimes in a cage choice assay than on the well watered cottonplants. Third instars raised on the well watered cotton plants were 1.5, 2.3, and 2.6 times heavier than those raised on cotton plants grown in the 1,500, 1,000, and 750 ml water/wk regimes (P < 0.05), respectively. Pupal weights followed the same trend(P < 0.05). Although beet armyworms preferred to oviposit on water deficit stressed cotton plants, the larvae fared poorly.