Insecticidal Toxicity of Spilanthol from &amp;lt;i&amp;gt;Spilanthes acmella&amp;lt;/i&amp;gt; Murr. against &amp;lt;i&amp;gt;Plutella xylostella&amp;lt;/i&amp;gt; L.

Anuradha Sharma,Neeraj Kumar,Rameshwar Singh Rattan,Bikram Singh,Vishal Kumar

doi:10.4236/ajps.2012.311189

Abstract

The present study explored the Spilanthes acmella Murr. for insecticidal principle, a plant of high value. The seed extract showed insecticidal activity against Plutella xylostella. Further, bioassay guided isolation of bioactive compounds resulted in insecticidal active molecule, which was identified with the help of ESI-MS and NMR. Highest activity of 95 - 100 percent was observed at low dose of 2 g/l with spilanthol, while 60 - 70 and 80 - 90 percent mortality at 5 g/l in crude seed extracts prepared in methanol and hexane after 48 hours exposure, respectively. LC50 of 1.49, 5.14, 5.04, 11.75 g/l was observed with spilanthol, crude seed extract of methanol, hexane, deltamethrin, respectively. The findings indicate the potential of S. acmella with potent insecticidal toxicity for the management of P. xylostella and other insects of agricultural importance.

Highlights

Spilanthes acmella Murr. is an annual herb belonging to the compositae family distinguishable from other species by its yellow flower head; the leaves and flower have pungent taste accompanied by tingling and numbness on the tongue
Highest activity of 95 100 percent was observed at low dose of 2 g/l with spilanthol, while 60 - 70 and 80 - 90 percent mortality at 5 g/l in crude seed extracts prepared in methanol and hexane after 48 hours exposure, respectively
The findings indicate the potential of S. acmella with potent insecticidal toxicity for the management of P. xylostella and other insects of agricultural importance

Summary

Introduction

Spilanthes acmella Murr. is an annual herb belonging to the compositae family distinguishable from other species by its yellow flower head; the leaves and flower have pungent taste accompanied by tingling and numbness on the tongue. It is an oligophagous species that feeds on plant species of the family Brassicaceae [18], which include economically important crops such as cabbage, cauliflower, broccoli, canola and Brussels sprouts. As such it is a worldwide pest, costing over the past US$1 billion to control annually. Pesticides have dominated attempts to control P. xylostella for more than 40 years [19,20,21,22,23] It was the first crop insect reported to be resistant to DDT and in many crucifer-producing regions. The present investigations were focused on exploring the insecticidal activity of S. acmella extract and bioassay-guided isolation of its con-

Methods

Results

Discussion

Conclusion