Life Cycle

In Maharashtra internode borer remains active throughout the year. About 5-6 generations are completed in one year. The moth lay eggs in masses usually on the upper surface of the leaf. The number of eggs in one mass varies from 5-60. The maximum number of eggs laid by a female in 415 and the minimum number of egg masses laid by a female is approximately fifty. The eggs hatch into larvae in about 5-7 days. The larvae enter into stem by burrowing through the internode. The larval period lasts for 25-35 days, after that they are converted into pupa. Before pupation the fully grown larva comes out of the tunnel formed into the stem and take shelter under the tightly fitting leaf sheath on the cane. There it secretes a silken cocoon and undergoes pupation in that. The pupal life lasts for 8-10 days and then adults emerges out. The life span of adults is approximately 3-5 days.

Nature of Damage

The crop is mostly attacked after the third month of planting till the harvesting is done. The caterpillars bore into the cane near the nodes hence it is called as internode borer.After entering into the cane, larva plugs the entry hole with excreta. The larvae move within the stem tissues damaging the nodes. Fresh borer attack is mostly found in the top five immature internodes. Caterpillars bore at the nodal region and enter the stem and tunnel up-wards in a characteristic spiral fashion. Entrance hole is usually plugged with excreta. Larvae feed and multiply in water shoots. One larvae found in a single cane damages 1-3 internodes. The length and girth of the infected internodes get reduced. Yield loss and juice quality deterioration occurs when the infestation is severe. Even 10% of the attack by this pest not only results in the loss of weight of the cane but it also causes deterioration in the quality of the sugar.

High dosage of nitrogen, waterlogged condition and presence of water shoots favors buildup of pest.