Efficient dose of thiamethoxam as a seed treatment product to reduce early damage of cotton leafhoppers Amrasca biguttula (Hemiptera: Cicadellidae) in Côte d'Ivoire

Abstract

Over the past decade, leafhoppers have become major cotton pests. In June 2022, a new species, Amrasca biguttula, appeared in Côte d'Ivoire and has caused losses of more than 50% of cotton production. To manage early infestations of this pest, the study was conducted with a view to determine an effective dose of thiamethoxam as a seed treatment for cotton. The effects of five doses (from 1 to 5 g of thiamethoxam/kg of seed) on leafhopper germination, growth and damage were evaluated. The results showed a better emergence rate and better growth with the 4 and 5 g of thiamethoxam/kg of seed. The use of 3 to 5 g of thiamethoxam/kg of seed significantly reduced damages (p< 0.001), with reduction rates of 60 to 80%. In conclusion, 3 to 5 g of thiamethoxam per kilogram of seed had an influence on the infestation levels of the leafhopper Amrasca biguttula. Thus, seed treatment with these doses will help manage early infestations of this leafhopper during the first 30 days after germination before the start of the insecticide treatment program.