Insecticides to control onion thrips (Thrips tabaci Lind.)

Abstract

By the late 1960's, DDT no longer afforded effective control of Thrips tabaci Lind. on onion in the Lockyer Valley, Queensland [see RAE/A 46, p. 478], and in 1969-70, 16 insecticides were tested in high-volume sprays for the control of the thrips. The results were assessed in terms of the numbers of thrips remaining on the plants following treatment. Although none of the materials tested afforded good control, the best results were obtained with 0.05% omethoate and methidathion at 1120 or 1685 litres/ha. A rapid increase in populations occurred during the second week after treatment, indicating that improved control could be achieved with a second application 7-10 days after the first, rather than at 14 days. The previously accepted standard treatment with DDT failed completely.