Effect of chlorpyrifos on survival, growth and reproductive performance of Eudrilus eugeniae (Kinberg)

Abstract

The present laboratory study was conducted to determine the effect of chlorpyrifos on growth and reproduction of the earthworm Eudrilus eugeniae. Chlorpyrifos was mixed with soil substrate at four different dose formulations i.e. D1 (2.5ml/1000ml); D2 (5.0ml/1000ml); D3 (7.5ml/1000ml); D4 (10.0ml/1000ml). Soil substrate withoutchlorpyrifos served as control. Growth and survival rates were determined till four weeks and effects on reproduction are assessed after eight weeks of exposure. A non significant decrease (p > 0.05) was observed in body weight of earthworms which was recorded on day 1, 2, 3, 7, 10 and 14. A dose dependent effect on cocoon production and survivability of hatchlings was observed in all treated groups. The effect of chlorpyrifos on life cycle of earthworm was more in dose D3 (54.25 days) when compared to control (28.75 days) while no worm survived in D4 dose. The present study revealed that chlorpyrifos at high dose levels(7.5ml/1000ml and 10.0ml/1000ml) affect the reproduction and growth of earthworms, primary bioindicators of soil fauna, whereas the base dose (5.0ml/1000ml) may be considered as safe for soil applications.