The Department of Horticulture is motivating farmers in Shimoga district to adopt biological methods to control root grub disease in arecanut crop.
A research conducted by scientists of the National Bureau of Agriculturally Important Insects (NBAII), Bangalore, has proved that Heterorhabditis Indica, a variety of entomopathogenic nematode, can control root feeding pests.
The root grub disease is caused by insects that belong to the Leucopholis Lepidophora species.
The insects damage the roots of the arecanut palm owing to which the supply of nutrients from the soil gets blocked.
The leaves of the infected arecanut palm turn yellow and if untreated, the palm dies in a short span of time.
According to an estimate, more than 1,500 acres of arecanut plantation in the district is infected with root grub disease.
The problem is acute in arecanut plantations located on the fringes of forests. So far, chlorpyrifos pesticide was used to control the disease.
Deputy Director of the Department of Horticulture M. Vishwanath told The Hindu that the excessive usage of chlorpyrifos killed beneficial microorganisms in the soil.
The powder formulation of Heterorhabditis Indica can be applied to the roots of arecanut palms when there is high moisture content in the soil.
The nematodes kill the pests within 96 hours.
At least 6 to 8 kg of powder is required for an acre of land. The expense to treat an acre of infected plantation using this method would be around Rs. 3,000.
The expense incurred to control the disease through chemical methods would also be the same.
Mr. Vishwanath said that studies say that nematodes do not have adverse effects on non-targets.
He said that few companies engaged in selling agriculture inputs have obtained NBAII’s permission to market the powder formulation of Heterorhabditis Indica.
The powder can be mixed with coco peat or cow dung and applied to the root of arecanut palm.
The department plans to organise awareness programmes on the biological method various parts of the district, he said.