Farm management practices and farmers' perceptions of stalk-borers of maize and sorghum in Lesotho

Abstract

A survey was conducted to gain insight into the perceptions of Lesotho's farmers with regard to insect pests of maize and sorghum, to identify management practices that could impact on stalk-borer numbers and to shed light on other farming practices such as variety selection and crop residue management. Field studies were conducted to determine the incidence and distribution of Busseola fusca (Lepidoptera: Noctuidae) and Chilo partellus (Lepidoptera: Pyralidae) larvae in sorghum and maize residues and to determine the effect of certain crop residue management practices on stalk-borer survival. Results indicated that farmers regard stalk-borers as important pests that sometimes need to be controlled. However, most farmers never apply control measures, mainly due to lack of resources. Residues of maize and sorghum plants are largely used as animal fodder with maize being cut and fed to animals after harvest. Sorghum crop residues are largely left on fields after harvest to be used by free-grazing animals. While stacks of maize stalks were not important in the winter survival of B. fusca larvae, stacking of sorghum ensures winter survival of C. partellus larvae. Detasselling of maize plants is commonly done at plant senescence and the upper halves of plants are fed to animals. Detasselling of maize plants had no effect on the number of borer larvae in plants at harvest.