Biology and Management of Legume Flower Thrips (Megalurothrips sjostedti) (Thysanoptera: Thripidae), a Major Insect Pest of Cowpea: A Review

Legume flower thrips, Megalurothrips sjostedti, is a serious insect pest of leguminous plants particularly cowpea. It attacks cowpea from pre-flowering to flowering stages. The insect is commonly found in tropical Africa and has been recorded to cause yield loss of up to 100%. Megalurothrips and undergoes gradual type of metamorphosis in which both nymph and adults cause damage by piercing the plant tissues and sucking up the released plant juices. Chemical control measures have been the mainstay and most widely used for its control due to its physical and immediate action, despites its several drawbacks. However, there are other control measures such as cultural (e.g. irrigation, tillage operation, planting date, crop rotation and intercropping) and botanicals (e.g. Piper nigrum) that have been developed as alternatives to synthetic chemical insecticides. Moreover, the use of biocontrol agents like predatory thrips and predatory mites (e.g. Amblyseius spp) and entomopathogenic fungi isolates (e.g. Beauveria bassiana, Metarhizium anisopliae), are also promising in suppression of pest thrips in both indoor and outdoor crops. More research is also needed on biology, economic importance, insecticides resistance techniques and biological control agents of M. sjostedti to provide appropriate control methods and increase cowpea production.