WOUND-INDUCED CHANGES IN THE ACCEPTABILITY OF TOMATO TO LARVAE OF SPODOPTERA-LITTORALIS - A LABORATORY BIOASSAY

Leaves of tomato (cv. Moneymaker) were artificially damaged and offered to Spodoptera larvae at a range of intervals following damage. Grazing levels on these leaves were compared with those on undamaged leaves on the same or different plants. In separate experiments, 3 leaves in a middle position on the main stem were clipped and after 48 h grazing levels on undamaged leaves above and below those damaged were compared with similar leaves from control plants. Within 8 h, grazing levels on damaged leaves were significantly lower than those on control leaves; within 24 h, leaves adjacent to damaged ones were similarly affected. These effects persisted for at least 7 days and leaves above and below those damaged were affected. There was up to 9-fold reduction in area consumed. The possible ecological consequences of reduced palatability at these levels are discussed.