LAUSR

The extracts obtained from Neem tree ( Azadirachta indica ) have been worldwide used indigenously as an insect pest antifeedant, and are known to be used by traditional medicine practitioners. The study was undertaken to investigate the impact of the synthetic pesticides and neem plant extracts on pollinators and crop yield of Pigeon Peas ( Cajanus Cajan ), and usage of the neem extracts on the field for pest management. The plant extracts were obtained in both aqueous and organic solvents. The insect pest infestation was more pronounced on untreated pigeon pea crop field compared to the field treated with neem extract or pesticide Dimethoate field. The field treated with neem plant extracts showed high frequency (abundance) and diversity in the numbers of pollinators of families Megachilidae and Apidae compared to the field treated with the pesticide Dimethoate. The activity of the active extracts was also performed in the dual-choice tests and No-Choice tests at different concentrations. The seed yield was high for neem extract treated field (2774 kg ha −1 ) than dimethoate treated (1602.8 kg ha −1 ) and untreated crop (1161.12 kg ha −1 ). Therefore the finding showed that neem based pest control is more efficient and increased yield production than synthetic pesticides/insecticides treatment. The research findings and observations from this report proved that beneficial insects are not affected or harmed with application of Neem plant extracts, and can continue to perform their valued services even after the application of Neem plant extracts, whereas their numbers decreased significantly on treated plants with synthetic pesticides. This is an indication that the most significant alternative strategies for insect control is the use of botanical pesticides particularly Neem extracts, and may be the most efficient means to replace a wide range of synthetic pesticides. To our knowledge, this is the first study that was done in East Africa specifically in one of the hottest province (Eastern province) of Rwanda, and can help to contribute in plant protection as the use of dimethoate is prohibited in various parts of the word.