Field screening of improved rice genotypes against the Asian rice gall midge (Orseolia oryzae Wood-Mason)

摘要

Asian rice gall midge (Orseolia oryzae Wood-Mason) is a serious pest in most of the rice growing areas in India particularly when high dose of nitrogen is used. In order to know the reaction of popular high yielding varieties (HYVs) and few improved genotypes to gall midge 87 genotypes were screened under natural field condition at 50-62 days after transplanting at zero and 120 kg N ha' based on appearance of silver shoot. Few genotypes from early group like Ananga, Annada, Kharavela and Shaktiman showed highly resistant reaction at both the level of nitrogen with 0% silver shoot. Cultivar Jajati and Suraksha showed moderately resistant reaction in mid group and Chaitanya in late group. Other cultivars/genotypes showed high infestation of gall midgeas observed from the incidence of silver shoots and are classified as either susceptible or highly susceptible at 120 kg N ha~(-1) level. Under high N level invariably there was high incidence of gall midge in most of the genotypes than the zero N level.