Author(s):

Vineeta Yadav, Shadab Ahmad and Kaneez Zahra

Abstract: Now a day, some botanicals have been used in crop fields and home applications as alternative to synthetic pesticides, to reduce the negative impacts to the environment. Present study was aimed to investigate the acute toxicity of biopesticide, Neem- Oil (NO) and the effective concentrations of Moringa leaf extract (MLE) on the mortality of zebra fish, Danio rerio. The four day acute bioassay test was performed using direct interpolation method and probit analysis. 130 adult zebra fishes were randomly selected and exposed to different concentrations of neem- oil and mortality rates were recorded. In direct interpolation method graphs were plotted between % mortalities and concentrations of toxicant at 24, 48, 72 and 96 hrs and LC₅₀ values were found as 3.2 ml/l, 2.6 ml/l, 2.2 ml/l and 1.8 ml/l respectively. Obtained data from direct interpolation method were computed by the probit analysis (statistical method) using Finney’s table. The LC₅₀ values at different exposure periods were found to be 3.155 ml/l for 24 hrs, 2.582 ml/l for 48 hrs, 2.162 ml/l for 72 hrs and 1.717 ml/l for 96 hrs. The upper confidence limits were 3.703, 2.971, 2.484 and 1.995 whereas lower confidence limits were 2.607, 2.193, 1.840 and 1.439 respectively. To assess the effective concentrations of MLE 110 fishes were exposed to different concentrations of MLE alongwith 24 and 96 hrs LC₅₀ of NO. On increasing the concentrations of MLE from 2-8 ml/l mortality rate decreased. Fishes remain alive at 8 ml/l and 6 ml/l of MLE against 24 and 96 hrs LC₅₀ of NO respectively. In the light of results, MLE can be suggested as the effective remedy against NO –induced mortality in zebra fishes.

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