THE EFFECTIVENESS OF SPINOSAD AGAINST GRANARY

Synthetic pesticides all over the world have traditionally been used as grain protectants (Arthur 1996). However, the number of pesticides currently registered for used is decreasing due to concerns over food and environmental safety and development of resistant pest populations. With the continuing requirement for residue-free grain, the need to assess alternative compounds is of increasing importance. Spinosad is an insecticide based on a fermentation product of the bacterium Saccharopolyspora spinosa Mertz & Yao, which was discovered during the 1980s (Mertz and Yao, 1990). It is effective at 1 mg (a.i.)/kg of grain against several species of stored product insects according to laboratory tests (Fang et al. 2002 a,b; Toews and Subramanyam 2003; Huang et al. 2004). Previous tests conducted with a liquid spinosad formulation have shown it to be highly effective against several stored-grain insects at 1 mg(a.i.)/kg (Fang et al. 2002 a,b; Toews and Subramanyam 2003), but very little work has been done with dust formulations (Nikpay 2007). Thus, the aim of our study was to assess the efficacy of a dust formulation (D