Resistance to Nephotettix virescens in Rice Varieties12

Greenhouse evaluations of 879 rice varieties and selections revealed that several are highly resistant to Nephotettix virescens (Distant), Resistant varieties generally were not preferred by adults and nymphs. Also, insects caged on these plants suffered high mortality, On highly resistant varieties, only 0-3% of the 1st in stars reached the adult stage, whereas on susceptible varieties 76-90% became adults. Except for a few varieties on which different in stars had different mortality rates, all in stars had identical mortality rates on resistant varieties. Adults had 4 to 8 times longer life spans and laid about 15 times more eggs on susceptible than 011 resistant varieties. The population declined rapidly on resistant varieties. Whereas it increased cumulatively on susceptible varieties. The insect made more probing punctures in the most resistant varieties than in the susceptible varieties but did little feeding; consequently, resistant varieties were seldom damaged. Histological studies of the leaf blades of resistant and susceptible varieties revealed no mechanical barrier to the insect’s feeding.