OCCURRENCE OF BEET ARMYWORM, SPODOPTERA-E XIGUA (HUBNER) (LEPIDOPTERA, NOCTUIDAE) ON YOUNG GROWING STAGE OF GARDEN PEA, PISUM-SATIVUM L

The seasonal abundance of larvae of the beet armyworm, Spodoptera exig ua (HUBNER), was surveyed by counting in garden-pea, Pisum sativum L., fields in Yamakawa Town in Kagoshima Prefecture, Japan, in 1992 and 1 993. S. exigua larvae were found after the plant height reached about 10 cm, with the maximum occurrence at around 13 to 26 cm. After the pl ant reached about 30 cm, the number of the larvae remained at less tha n three per 100 plants until late November. This pattern was observed in all fields irrespective of the seeding time From mid-August to earl y October. A delay of about 10 days in seeding time (late August) redu ced the maximum abundance of larvae to < 50% of that in fields seeded in mid-August. Further delayed seeding (early October) reduced the max imum abundance to 10%-20%. Pheromone trap catches from August 1992 to March 1994 showed six occurrence peaks for nine traps in 1993. The fir st peak occurred in late April, the 2nd to 4th between June and August , the 5th in late September to early October, and the last in mid- to late-November. The 5th and 6th peaks also occurred around the same tim e in 1992.