Insecticides to control sorghum midge Contarinia sorghicola (Coq.)

Abstract

To determine a suitable alternative to DDT for the control of Contarinia sorghicola (Coq.) on sorghum, 7 insecticides (including DDT) were tested as high-volume sprays at intervals of 3-4 days during the flowering period in Queensland in 1969-71. Efficacy was assessed in terms of seed set. Monocrotophos, diazinon and carbaryl showed promise in screening trials, and were carried through to dosage level trials. Monocrotophos at 280 g/ha was the most effective but has been reported to be phytotoxic to sorghum. The next most effective compound, diazinon (applied at 280 g/ha), has become a general recommendation for the control of C. sorghicola in Queensland. ADDITIONAL ABSTRACT: In field trials on the Darling Downs in Queensland in 1969-71 the effect of 7 insecticides on the grain yield of plants infested with sorghum midge was studied. Monocrotophos, DDT, diazinon and carbaryl at 730 1/ha increased sorghum grain yield from 1.51 to 5.23, 6.02, 4.48 and 4.85 kg/plot, resp.