STUDIES ON ECONOMIC THRESHOLD OF CONTROLLINGRICE LEAF ROLLER,CN APHALOCROCISMEDINALIS GUENEE
稻纵卷叶螟经济阈值的研究

In this study, not only the amount of feeding rice leaves by the larvae of leaf roller in various instars has been measured in the laboratory, but also the grain yield, the percentage of empty grain,the rate of yield loss and the weight of 1,000 grains per plot have been surveyed in the paddy field planted to various rice varieties and encroached by the larvae of rice leaf roller in various population densities. Besides, the relationship between the area of injured flag leaves and the yield loss per plot, t...`