Abstract

Valuable contributions have been made to investigate the effect of temperature and humidity on the development, growth, metabolism, longevity, fecundity, distribution etc. of various insects particularly storage pests, predators and parasites, and relatively fewer crop pests (Cook, 1927; Pruthi and Pradhan, 1945; Pradhan and Vishwanathan, 1959; Narayanan et al., 1962 etc.), but very little has been studied to assess the overall population incidence during different seasons, and consequently no estimate of actual losses even on 'guesstimates' are available. Simultaneously, on the other hand, it becomes imperative to device suitable chemical control for the population reduction, since the loss caused by insect pests, in general, is a function of their population incidence. With this view, therefore, a study was undertaken in lucerne (Medicago sativa Lin.) which is an important fodder crop throughout Rajasthan, harbouring a large and varied insect population responsible for substantial tonnage besides considerable nuisance to feeding animals. For studies on frequency of pest infestation in case of maize borers and lucerne weevil, vide Kushwaha and Jain (1963 a,b)

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