TOXIC AND REPELLENT EFFECTS OF THREE BOTANICAL OILS ON APHIS CRACCIVORA KOCH (HOMOPTERA: APHIDIDAE)

Abstract

In the present study, three botanical oils namely neem, karanja and mahogany were tested against the adult and nymph of Aphis craccivora Koch to evaluate the toxic and repellent effects under laboratory conditions in the Department of Entomology, Hajee Mohammad Danesh Science and Technology University, Dinajpur during September 2016 to January 2017. The results indicated that all the botanical oils had different levels of toxic and repellent effects and found effective for controlling bean aphid. Among the botanicals, the highest toxicity (mortality, 29.83%) was found in mahogany oil whereas karanja oil showed the lowest toxic effect (mortality, 22.96%) against the adults of bean aphid. Mahogany oil showed the highest repellent effect (77. 33%) i.e. class IV among all the botanical oils applied. On the contrary, karanja oil showed the lowest repellent (34.00%) effects, i.e. class II and neem oil belongs to the repellency class III. In case of nymph, the highest mortality was found in mahogany oil (mortality, 28. 62%) and the lowest was found in neem oil (mortality, 27.21%) though these are statistically identical. The highest repellency was found in the mahogany oil (77.33%) that belongs to the repellency class IV, whereas, the lowest repellency was found in karanja oil (55.00%) which was in the repellency class III. However, all botanical oils showed toxic and repellent effects against bean aphid but mahogany oil showed the highest performance among all the oils.