Relative Susceptibility of Rice Genotypes to Lesser Grain Weevil Sitophilus oryzae (L.)

A total of 11 rice genotypes were screened for their relative susceptibility to the lesser grain weevil Sitophilus oryzae (L.), under no-choice and free-choice conditions at Post-harvest Technology Centre, Bapatla during 2022-23. Under free-choice conditions on rough rice, the variety Teja recorded the highest adult population (61.33) of S. oryzae, while the advanced culture BPT 3111 recorded the lowest (18.0) at 60 days after release (DAR). In milled rice, BPT 2841 was the most susceptible genotype, recording the highest weevil populations under both free-choice (110.33) and no-choice (112.67) conditions. In contrast, the genotypes Bapatla Mahsuri and BPT 3111 were least preferred, with significantly lower adult weevil populations in milled rice under free-choice (12.33 and 13.33, respectively) and no-choice (49.67 and 47.67, respectively) conditions. The high susceptibility of BPT rice 2841 was further confirmed in the dual choice test, where it supported the maximum progeny emergence (327.50 adults), higher percent grain weight loss (2.40) and a slightly shorter development period (47.17 days) compared with Bapatla Mahsuri that recorded fewer progeny (56.67 adults), lower weight loss (0.49 %) and a longer development period (48.37 days). Overall, both rough and milled rice grains of BPT 3111 were consistently less susceptible to rice weevil, indicating its potential as a relatively resistant genotype under storage conditions.