<b>Solvation Study of Neem Oil in Aqueous Sodium Dodecyl Sulphate at different Temperatures</b> The plant diseases have significant role in agriculture in terms of reduction in yield and economy. In agriculture, for thousands of years, people have been using neem oil as a natural insecticide, fungicide and bactericide. Neem pesticides have been widely used to kill or manage the population of pest. Neem oil is hydrophobic in nature in order to emulsify it in water for application purpose, it must be formulated with appropriate surfactants. In the present study, neem oil was mixed with sodium dodecyl sulphate SDS . The density, viscosity and ultrasonic velocity of aqueous solutions of SDS with neem oil have been measured. The compressibility behaviour of solutions provides very useful information related to solute and solvent interactions. The solubility of neem oil has been investigated by the estimated values of solvation parameters. The experimental data have been used to calculate the solvation parameters such as adiabatic compressibility, molal hydration number, apparent molal compressibility, apparent molal volume, limiting apparent molal compressibility, limiting apparent molal volume and their constants and viscosity co efficients A and B of Jones Dole equation. Based on the results, the nature and types of interactions in the solutions are discussed. The growth performance of cowpea crop in pot culture experiment is also analysed. After manifestation, periodical records of symptoms of diseases due to insects are noted. The biometric observations of crops at frequent intervals are enumerated. The results obtained from ultrasonic method and pot culture experiment are in consonant with each other. SDS neem oil adiabatic compressibility hydration number apparent molal compressibility apparent molal volume pot culture experiment 652-661 Issue-1 Volume-2 P. seethalakshmi | K. Renuka Devi | R.Seema | J. Benazir Jiya