Synergistic effect of garlic oil and Bacillus thuringiensis toward Spodoptera exigua

In this work we evaluated the synergistic effect of pure garlic oil combined with the spore-crystal complex of Bacillus thuringiensis HD133 to kill Spodoptera exigua larvae. Toxicity bioassays were conducted with 75 neonate larvae per treatment and a control, to determine mortality seven days after and growth inhibition rate four days after. Individual results indicated that 5% pure garlic oil caused 80% mortality and the spore-crystal complex at a concentration of 80 µg/ml caused 37% mortality. Combination of both agents at the same concentrations caused 100% mortality in neonate larvae. The growth inhibition rate caused by the spore-crystal complex and the pure garlic oil was 93% and 34% respectively for survivor larvae. A synergistic effect is observed when pure garlic oil and the spore-crystal complex are combined to kill S. exigua larvae. This combination can be a valuable tool in the bio rational control of S. exigua.