Seasonal Fluctuations in the Abundance of the Monkey Pod Moth, Polydesrna umbricola, in Hawanii123

Abstract

The monkey pod moth, Polydesma umbricola Boisduval, is a serious pest of the monkey pod tree, Samanea Saman (jacq.) Merrill, in Hawaii. Its larvae feed on the fresh foliage of the trees, causing defoliation and death of the terminal branches. During 1963-64 its seasonal abundance was investigated by making monthly counts of the larvae trapped in specially made burlap bands Wrapped around the tree trunks. The pest was abundant in March and September 1963, and again in May and June 1964. These population peaks occurred when there was an abundance of fresh foliage on the trees. From May to July 1963, its numbers fluctuated at a much lower level in spite of the abundance of fresh foliage. This differential was undoubtedly due to the activities of its numerous parasites and predators. The black witch moth, Otosema odora (L.), shares the same habitat with P. umbricola , but because of low numbers it does not seem to influence the abundance of the latter.