EFFECTS OF CONTACT DURATION OF 0.5% THIOTEPA ON THE ADULT VIVIPARAE AND SUBSEQUENT GENERATIONS OF THE PEA APHID, ACYRTHOSIPHON PISUM (HOMOPTERA: APHIDIDAE)

Abstract

The compound tris (1-aziridinyl) phosphine sulphide, known by the trivial name thiotepa, has been tested against few aphids. Considerable reduction in fecundity occurred due to thiotepa treatment of the cabbage aphid, Brevicoryne brassicae (L.) (Bonnemaison 1966). In 0.3% thiotepa-treated Aphis fabae Scop. a 90% decrease in reproductive capacity was observed by Steffan and Stüben (1976). Sharma and Thériault (1980) tested 0.5% thiotepa on various nymphal instars of the pea aphid, Acyrthosiphon pisum (Harris), and observed up to 83% decrease in fecundity of those treated in first and second instars. The third and fourth instar aphids were much less influenced by thiotepa. The effects of thiotepa on the adult viviparae of the pea aphid are unknown and nothing has been recorded on the transmissibility of thiotepa-caused sterility to progeny. Further to the results of Sharma and Thériault (1980) this paper describes the effects of two contact periods with 0.5% thiotepa on the adult viviparae of A. pisum and delayed effects on subsequent generations.