Pyrethroid Resistance in the Bollworm Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) in West Africa
Mar 7, 2019
The sensitivity of bollworm, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) to pyrethroids has been monitored in co-operation with CIRAD-CA in research laboratories of National Research Institutes in West and Central Africa for more that ten years. This survey over the last three years, enabled observations of a tendency for resistance to pyrethroids to develop in bollworm. At the same time, loss of efficacy of pyrethroid based sprays has been observed in farmers’ fields in Benin, Burkina Faso, Côte d’Ivoire and Mali. The LD50 recorded in the laboratory on different strains of H. armigera in 1997 and 1998 leads to the factors of resistance varying from 10 to 100 for cypermethrin and deltamethrin. Short term proposals are 1) the implementation of a field survey using the vial test method to learn more about spatial re-partition of the resistant population; b) calendar based spraying programmes with reduced use of pyrethroids; and c) threshold based interventions to control bollworm.