SIMULATING DAMAGE OF LEAFMINER, HYDRELLIA PROSTERNALIS AND ITS EFFECT ON RICE GROWTH CHARACTERISTICS AND GRAIN YIELD

Abstract

Rice a vital food crop, in Egypt, particularly with the shortage of wheat production. Rice plants are subjected to several insect infestations which impair the productivity, consequently the growers tend to use insecticides for pest control. Unfortunately, they use these chemical insecticides regardless of insect infestation level. The current investigation was carried out at the Experimental Farm of Rice Research and Training Center, Sakha Agricultural Research Station during 2013 and 2014 rice seasons. Six defoliation levels; 0, 20, 40, 60, 80 and 100% were applied one month after transplanting to find out the effect of leaf removal on rice growth characteristics and yield. The whole leaves, at certain levels, were cut by hand. Leaf chlorophyll content was not affected by any of simulation levels. Plant height, leaf area index and dry matter content were not reduced due to defoliation up to 40 or 60%. These characteristics displayed significant reduction at 80 or 100% defoliation. As for yield components, the panicle weight was not significantly reduced up to 40% defoliation, but at levels of 60, 80 or 100% defoliation, the panicle weight was significant negatively affected. Also, the 1000-grain weight was significantly reduced at higher levels of defoliation (80-100%) compared to lower ones (20-60%). The grain yield was reduced by 14-17%, 21 and 34% at 60, 80 and 100% defoliation, respectively. Thus, rice leafminer infestation up to 40% could be considered not alarming to the rice growers.