Techniques For Predicting The Insecticide Dose Received By The Desert Locust, Schistocerca Gregaria (Orthoptera: Acrididae) When Settled

Khaled El-Gadgoud
National Committee for Desert Locust Control, Libya

Abstract

An equation was developed to assess the correlation between the number of droplets on the collected dead adults Schistocerca gregaria and the volume of these droplets. The correlation values indicated that the relationship between droplet numbers and their volumes was strongly positive. Both water and oil-based formulations produced a highly positive correlation between spray droplet number and their volumes for all locust positions. The two variables showed a highly significant relationship (P<0.01) for all positions tested. Regression equations were calculated for both water and oil-based formulations These were (y = 0.002(x) + 0.16) and (y = 0.0017(x) + 0.060), respectively. These two equations can be used to predict the volume of droplets from known droplet numbers. The regression equations (Pr) for all positions were used as essential parts of the equation. The prediction obtained through the equation developed suggested that locusts receive a very high dose of active ingredient if malathion and fenitrothion are applied at the recommended field application rate. It also suggested that the application rate can be reduced to one third for malathion and one fifth for fenitrothion.