Biochemical traits of cucumber genotypes in relation to leaf infestation by Aulacophora foveicollis Lucas (Coleoptera: Chrysomelidae)

Abstract

The present study was carried out in cucumber, Cucumis sativus L. to identify the resistant sources for red pumpkin beetle during 2009 and 2010. The study of red pumpkin beetle resistance or tolerance was carried out in open field conditions without spraying any insecticide. Plants genotypes possess different biochemical properties, which resultantly induce in them different mechanisms of resistance. This mechanism enables the plants to avoid, tolerate or recover from the effects caused by insect pest. The results of the present studies revealed that there were significant variation in tested cucumber genotypes for percentage leaf infestation and beetle density per plant. Nepal Local was found least susceptible to Aulacophora foveicollis followed by Sikkim Cucumber, IC-355960, and IC-429994 whereas; Khira Paprola was most susceptible followed by Mohini-5300 and KCU-006 over check Khira-90. There was a significant positive correlation of per cent leaf infestation and number of beetles per plant with cucurbitacin content, non-significant correlation with total sugars, total free amino acids and total phenols.