Abstract
The beet armyworm, Spodoptera exigua (HUBNER) is well known as an important pest of various kinds of economic plants in many countries. In Japan, only a few reports on beet armyworm and its damage have been published.
Recently in Kagoshima Prefecture, the beet armyworm has been observed in green onion fields, causing serious damage.
The current studies on the ecology and control of the beet armyworm were initiated in 1985. The present report deals with the developmental biology of the beet armyworm in relation to temperature. In the laboratory experiments, the threshold temperatures for development and the effective thermal totals of egg, larva, pupa and egg to moth emergence were estimated to be 10.5, 15.3, 15.6 and 15.3C and 49, 162, 74 and 270 day-degrees, respectively.
