Control of the African army worm Spodoptera exempta walker (lepidoptera: noctuidae) in kenyan fields with highly effective strains of Bacillus thuringiensis berliner

Abstract

Good control of second and third instar larvae of Spodoptera exempta was obtained in cereal fields using spray application of powder preparations of different Bacillus thuringiensis (Bt) strains: Bt24 (var. entomocidus), IH‐A (var. aizawai) and K26–21 (new isolate). These Bt preparations also protected cereal crops from damage caused by fourth to sixth instar larvae, but lower rates of larval mortality were obtained (50%‐80%). Spray applications of Bt preparations combined with a ‘sweeping out’ operation using a Californian sweep net in grass fields surrounding susceptible crops, were shown to be effective in preventing massive migration of large larvae to the crops, especially in small farms.

Keywords:

• African armyworm
• Spodoptera exempta
• Bacillus thuringiensis
• biological control