Hexane, ethanol and acetone extracts of cayenne pepper, sweet pepper and long cayenne pepper as funigant toxcity against Sitophilus zeamais (MOTSCH) coleoptera; curculionidae infesting stored maize grains

Organic solvents (Hexane, Ethanol and Acetone) extracts from fruits of Cayenne pepper, Sweet pepper and long-cayenne pepper were evaluated for their fumigant toxicity against the maize weevil Sitophilus zeamais and damage to grains (T-swan variety), under laboratory conditions. Bioassays were conducted at five concentration levels of 0.5, 1.0., 2.0, 5.0 and 10.0ml/20g maize grain. Parameters assessed were; adult mortality, adult emergence, grain damage and weight loss due to infestation by S. zeamais. Results indicated that, Cayenne pepper fumigant from hexane extracts at 0.5–10ml/20g grains caused significant (P<0.05) reduction in adult mortality and adult emergence by S. zeamais, reduced grain damage and grain weight loss due to infestation. Adult mortality was found to be linearly and positively correlated with increasing concentration of extracts (r=+0.80). In contrast, adult emergence, mean grain damage and mean grain loss were negatively correlated with increasing concentration of extract with an average correlation coefficient (r) of –0.48. Sweet pepper and long Cayenne pepper fumigant showed low fumigant toxicity in comparison with solvents controls with highest values in all parameters assessed. Hexane extracts of Cayenne pepper as fumigant at 0.5–10.0ml/20g maize grain significantly by resulted in 100% adult mortality and 0.0% –1.25%. F₁ adult emergence, grain damage and weight loss at 1.0ml -10.0ml/20g maize grain. While, acetone and ethanol pepper fumigants were ineffective.