Handsen Tibugari

Resistance Status of Cotton Pests in the Era of Zimbabwe Land Reform: Cotton Insecticide Resistance Management Strategies Handsen Tibugari

A study to investigate the resistance status of Helicoverpa armigera (Hübner) to fenvalerate 20 EC (Cyano (3-phenoxyphenyl) methyl 4-chloro-?-(1-methylethyl)benzene acetate) and Tetranychus spp. to amitraz 20 EC (n'-(2,4-dimethylphenyl)-n-[[(2,4- dimethylphenyl)imino]methyl]-n-) in view of the Zimbabwe Land Reform Programme was carried out at the Cotton Research Institute (CRI) during the 2005/06 cotton growing season. Field populations of H. armigera and Tetranychus spp. were collected from cotton growing areas of Sanyati, Umguza, Chisumbanje, Chinhoyi and the CRI in Kadoma and exposed to bioassays. The African bollworm leaf disc technique and the red spider mite attached leaf-dipping technique were used to assess responses of the African bollworm and red spider mite (respectively) to the pesticides. Susceptible laboratory populations served as the standard populations and their responses were compared with those of the field populations. The graphical method and MSTAT-C probit analysis computer programme were use.