Neem (Azadirachta Indica A. Juss) callus induction and its larvaecidal activity against Anopheles Mosquito

The aim of this study was to establish an effective protocol for callus induction from the leaf explant of the neem (Azadirachta indica A.Juss) and to investigate its larvaecidal activity against the larvae of Anopheles mosquito. The effects of growth regulator, basal media strength, sucrose and crude aqueous extracts were investigated. Growth regulator effect was studied by using four different concentrations (0.5, 1.0, 1.5, and 2.0 mg/L) of indolyl- 3- acetic acid (IAA), indolyl- 3- butyric acid (IBA), naphthalene acetic acid (NAA) and 2,4-dichlorophenoxy – acetic acid (2,4-D) alone or in combination with 0.5 mg/l of 6-bezyladenine (BAP). IBA alone or in combination with BAP produced the highest callusing percentage and the best callusing degree compared to other auxin at the same concentrations. Auxin when supplied in combination with BAP did not induce any significant increases in callusing percentage or degree of callusing. However, the times required for callus to be developed was shortened and the quality of the induced callus was improved. Increase in callus growth on medium with low salt and sucrose concentration was greater than on medium supplemented with high salt and sucrose concentration.

The effect of crude aqueous extracts obtained from the neem leaf callus and neem fresh leaf against the larvae of Anopheles mosquito was investigated separately. Exposure of the larvae to 20 ml extracts of leaf callus and fresh leaf for 24 hours led to 100 and 63% mortality rate, respectively.