Pesticides for locust control

Abstract

The factors influencing the choice of insecticides for locust control are effectiveness, safety in use, relative cost, and the formulations available. The relative importance of these factors varies with the scale of control. In small scale control by farmers safety and simplicity are paramount and a BHG dust is commonly used, but in large scale control operations by specialized organizations more toxic formulations ultra-low-volume (u.l.v.) concentrates and methods of application requiring considerable skills can be used. The remarkable effectiveness of dieldrin as a stomach poison appears to be due to its conversion to photodieldrin after application. Gases of poisoning following large scale control operations are rare, and fatalities in man unknown. Alternatives to organochlorine insecticides include fenitrothion, already recommended and used on a large scale against adults. Against nymphs the correct dosage of fenitrothion would cost nearly 11 times as much as that of dieldrin. Recent experimental work with new insecticides has included safety tests with domestic animals and measurements of persistence. 1 pg deposits of cyanofenphos, decamethrin and mecarphon, as well as of dieldrin and photodieldrin, on wheat seedlings left in the open under tropical conditions for two days, killed 80 % or more first instar nymphs of the Desert Locust which fed on them.