Protection of stored grain currently relies on synthetic pesticides such as the fumigant phosphine or dust formulations such as pirimiphos methyl (Anonymous 1995). However, the widespread use of these pesticides have significant drawbacks including increased cost, handling hazards, concern about pesticide residues on grains, and threat to human health and environment (Paster and Bullerman 1988). Public awareness of these risks has increased interest in finding safer insecticides or alternative stored product protectants to replace synthetic chemical pesticides. One such alternative is the use of natural plant protectants that have pesticidal activity, because they tend to have low mammalian toxicity, less environmental effects and wide public acceptance (Liu and Ho 1999; Hamilton-Kemp et al. 2000; Singh and Tripathi 1999; Paster et al. 1995; Don-Pedro 1996).