Azadirachtin biopesticide: A review of studies conducted on its analytical chemistry, environmental behaviour and biological effects

Abstract

This paper provides a brief review of studies conducted in our laboratory on the analytical chemistry, environmental behaviour and biological effects of azadirachtin‐A, a neem‐based pesticide. Azadirachtin‐A (AZ‐A) was isolated from samples of neem seed kernels, leaves, bark, root and stem, obtained from Kanthayapalayam, South India. The extracts were subjected to column cleanup and AZ‐A concentration was quantified by using a high‐performance liquid chromatographic (HPLC) method. A flow diagram is given describing the procedures involved. AZ‐A was also isolated from four commercial formulations and from several forestry substrates, and its concentration in each sample was quantified by HPLC. To investigate the environmental behaviour of AZ‐A, five studies were conducted: (i) persistence of AZ‐A on balsam fir and red oak foliage, (ii) dissipation of AZ‐A in forest nursery soils, (iii) leaching in sandy loam forest soil, (iv) adsorption and desorption of AZ‐A in sandy loam soil, and (v) rate of hydrolysis in buffer solutions and natural waters. A summary of the data is given in the paper. The biological effects of azadirachtin on two‐spotted spider mites infecting young trembling aspen plants was studied after applying AZ‐A and its four formulations onto aspen leaf discs. The repellency, oviposition deterrence, mortality and fecundity were investigated. The data indicated that the toxic effects were significantly influenced by AZ‐A concentration and formulation ingredients. Th…