Effect of neem oil based nanoemulsion on egg parasitoid, Trichogramma chilonis (Ishii) (Hymenoptera: Trichogrammatidae)

Abstract

Botanical biopesticides are alternative to hazardous synthetic insecticides. In the present study neem oil based nanoemulsion was synthesized using neem oil and tween 80. The particle size was estimated as 159.2 nm. The emulsion was characterized using particle size analyzer and TEM to confirm the formation of nano emulsion of neem oil. Trichogramma chilonis (Ishii) is an effective egg parasitoid of lepidopterous pests. It controls pests in eggs stage prior to its damaging to crops. The parasitoid is vulnerable to insecticides or oil sprays applied to the crops. The present study revealed the effects of neem nanoemulsion with T. chilonis under the controlled laboratory conditions. Different concentrations i.e., 50, 100, 500, 1000, 5000, 10000 ppm were tested on T. chilonis. The biological effects viz., per cent parasitism, adult emergence were found significantly reduced and increased mortality in all the concentrations of macroemulsion of neem oil (66.78 ± 0.50, 71.69± 1.02; 48.45 ± 0.35, 52.26 ± 0.60; 31.75 ± 0.35, 26.00 ± 0.39 in 10000 and 5000 ppm, respectively) as compared with nanoemulsion (75.40 ± 0.03, 78.26 ± 0.29; 52.50 ± 0.52, 57.85 ± 0.60; 19.57 ± 0.27, 16.25 ± 0.25 in 10000 and 5000 ppm, respectively and control (88.00 ± 0.12; 82.00 ± 1.26; 2.25 ± 0.02, respectively). These studies showed that the 10000 and 5000 ppm concentrations of nanoemulsion of neem oil were found less toxic to T. chilonis