Yellow stem borer is a serious pest of rice throughout India and South East Asia. Stem borer occurs both in kharif and rabi seasons.
Moderate to severe incidence is noticed in nursery, planting to mid-tillering and panicle initiation stages. Heavy infestation results in 40-60 per cent yield loss.
Though considered predominantly as a monophagous pest, it has also has been reported from wild rice types, and other monocot weed plants present in the rice ecosystem.
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Damage symptoms
Symptoms of damage include presence of brown colored egg masses near leaf tip in nursery and early transplanted plants.
The egg masses are laid in oval patches of 80-150 eggs near the tip of leaf blade and they are covered with buff coloured hairs.
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Tiny pale yellow larvae hatch out from the eggs in 5 to 8 days, enter the leaf sheath, feed for 2-3 days and then bore into the stem near the node.
Usually only one larva is found inside the stem. The larva grows for a period of 40 days and pupates inside the stem in a white silken cocoon for 7-11 days. The entire life cycle lasts for 35-50 days depending upon the environment. The adults do not feed and live for 4-10 days.
Management measures
Use less susceptible varieties and adjust the dates of planting to evade the incidence of the pest.
Clip off the tip of the seedlings before transplanting and collect and destroyed stem borer egg masses present on the transplanted young rice plants
Soak the roots of the seedlings in 0.02 per cent chlorpyriphos for 12-14 hrs before transplanting to give protection from the attack of stem borer up to 30 days.
Avoid close planting and continuous water stagnation and pull out and destroy the affected dead heart tillers.
Set up light traps to attract and kill the moths.
Use TNAU YSB pheromone lures and traps from 15 days after transplantation with lure replacement on 25, 46 and 57 DAT traps to monitor and manage stem borer males
Harvest the crop up to the ground level and disturb the stubbles to destroy the diapausing larvae and pupae.
(J. Jayaraj is Professor and N. Muthukrishnan is Professor and Head, Department of Entomology, Agricultural College and Research Institute, Madurai 625 104, Phone :0452-2422956, email: agentomac@tnau.ac.in)