A comparison of efficacies of bran-based baits containing diflubenzuron, teflubenzuron, and fenitrothion against desert locust, Schistocerca gregaria (Forsk.) (Orthoptera:Acrididae)

Bioassays of two insect growth regulators (IGRs), diflubenzuron (Dimilin) and teflubenzuron (Nomolt), and an insecticide, fenitrothion (Dicofen), delivered in bran baits to the fifth instar hoppers of the desert locus ( Schistocerca gregaria (Forsk.)) were conducted in the laboratory. Neither of the IGRs showed repellent effects, but fenitrothion induced repellency at doses greater than 250 g ml-1. Fenitrothion was, however, shown to be the most efficacious, both in terms of its speed of action and the concentration required to cause 100% mortality of treated insects. Bait incorporating this insecticide caused 100% mortality at 100 g ml-1. Of the two IGRs, teflubenzuron was shown to be the more toxic and gave positive, significant probit regression. The toxicity of diflubenzuron was found to be inconsistent and no significant probit regression was found. Both diflubenzuron and teflubenzuron caused abortive moult, and most survivors developed twisted or mis-shapen wings. Incorporation of these toxicants into bran baits could serve as a means of controlling locusts.

Keywords:

• Bait
• Diflubenzuron
• Fenitrothion
• Schistocerca Gregaria
• Teflubenzuron