Studies on the biology and reproductive behaviour of yellow stem borer, Scirpophaga incertulas Wlk.

The biology of Scirpophaga incertulas Wlk studied at CRRI, Cuttack, Orissa revealed that average incubation, larval, pre-pupal, pupal, pre-oviposition, oviposition, post oviposition, male and female longevity, total life cycle of male and female were completed in 6.71, 34.74, 1.19, 7.52, 1.13, 1.32, 0.27, 2.64, 2.96, 52.6 and 55.4 days and 7.2, 39.38, 1.22, 8.06, 1.21, 1.41, 0.41, 2.75, 3.12, 58.69 and 62.14 days during Sept.-Oct. and Oct.- Nov., respectively. The fecundity, egg masses/adult, no. of eggs/eggmass, number of larvae emerged/eggmass, % adult emergence and sex ratio (male:female) is 142, 2, 112.8, 82.6, 52.38 and 1:1.88 in the moth of Sept.-Oct. and 160.7, 2.2, 126.3, 108, 57.26 and 1:2 during Oct.-Nov., respectively. Neonate larvae failed to make entry into fully matured 150 days old mother tillers. The larvae could survive beyond 20 days on cut stem pieces and spikelets inside the unopened boot leaf. They could survive up to 8th day on the mid rib of the leaf.