Abstract

The successful storage of his grains free from insects is a serious problem for the ryot. The grains have to be stored for some time, longer or shorter, before a ryot can dispose them off for food or for seed and during this period they are liable to be spoiled in various ways: their suitability for food may deteriorate or they may suffer in their germi nating capacity; and insects contribute largely to this damage, the loss from which may amount to several lakhs of rupees in a year. It has been calculated that cholam (sorghum) grains alone are liable to damage upto 25 per cent during the course of storage for a year; in very bad cases it may be more. According to the Season and Crop Report for the year 1938-39 published by the Madras Government 1,265,300 tons of cholam were produced in this Presidency in that year, valued at Rs. 94,867,500. At a low estimate of 10 per cent the loss due to insects would come to 9 millions of rupees. This loss has been calculated to be caused by only one species of insect the rice weevil. If we take into consideration also other insects that take their toll, we can easily imagine, how great the loss caused to cholam grains in our presidency would be due to insects. Insects attack- ing grains are many; this paper deals with observations regarding only two of these, viz, the rice weevil on cholam and the paddy-borer beetle on paddy. The rice weevil, though commonly so called, is more a serious pest of cholam grains here than of paddy.

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