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Effect of Post-Treatment Temperature on the Insecticidal Activity of Neem, Azadirachta indica A. Juss. Seed Extract on Schistocerca gregaria (Forskal): A Preliminary Report

  • J. M. KabaruEmail author
  • R. W. Mwangi
Short Communication

Abstract

The influence of post-treatment temperature on the insecticidal activity of Azadirachta indica (A. Juss) seed extract against the desert locust, Schistocerca gregaria (Forskål) is reported. In tests on adults, the toxicity of crude A. indica seed extract increased by about 10-fold when the post-treatment temperature was raised from 22°C to 40°C. This temperature-dependent toxicity was observed in insects treated either topically or via injection. This phenomenon could partly explain the wide variability in efficacy of neem extracts reported by different investigators.

Key Words

botanical insecticides neem temperature effects Azadirachta indica Schistocerca gregaria 

Résumé

L’article expose l’influence des températures après traitement, sur l’activité insecticide des extraits de graines du nime, Azadirachta indica (A. Juss), utilisés dans la lutte contre le criquet du désert, Schistocerca gregaria Forskål. Au cours des essais sur les adultes, les extraits bruts obtenus des graines de A. indica ont accru leur activité par 10 fois, quand la température après traitement passait de 20°C à 40°C. Cette interdépendance de la toxicité et la température fut observée chez les insectes traités par application externe ou par injection. Ce phénomène pourrait expliquer en partie, la grande variabilité d’efficacité des extraits de nime rapportée par plusieurs chercheurs.

Mots Clés

insecticides botaniques nim effets thermiques Azadirachta indica Schistocerca gregaria 

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Copyright information

© ICIPE 2000

Authors and Affiliations

  1. 1.Department of ZoologyUniversity of NairobiNairobiKenya
  2. 2.Research and Extension DivisionEgerton UniversityNjoroKenya

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