Coimbatore
A severe outbreak of the black-headed caterpillar has emerged as a major concern for coconut growers in the northern parts of Sulur taluk in Tamil Nadu, with the destructive pest damaging plantations and threatening yields across several villages.
Farmers have urged the horticulture department to step up control measures as the infestation continues to spread. The outbreak was first reported from Mopperipalayam, where growers said several coconut trees have suffered extensive damage. They warned that the pest is now spreading to neighbouring villages, including Kaduvettipalayam, Kittampalayam and Paduvampalli, aided by the prevailing north and easterly winds.
The black-headed caterpillar (Opisina arenosella) is among the most destructive pests affecting coconut palms. The larvae feed on the underside of leaves by scraping away the green chlorophyll tissue, drastically reducing the tree’s ability to carry out photosynthesis. As the infestation worsens, the affected fronds dry up, leaf production declines, and coconut yield falls significantly, resulting in heavy losses for farmers. Growers in the affected villages said they have observed dried and discoloured fronds, along with insect excreta and silken webs on the underside of the leaves, indicating widespread infestation.
They have appealed to the horticulture department to intervene immediately before the pest spreads further and causes irreversible damage to plantations. Horticulture department officials have advised farmers to adopt an integrated pest management strategy to contain the outbreak. They recommended pruning and burning severely infested fronds to destroy larvae and pupae and prevent further multiplication of the pest. Officials also suggested biological control through the release of parasitic wasps, particularly Bracon species, which naturally attack the caterpillars. Considering the prevailing wind direction, parasitoids should preferably be released from the western side of plantations during the cooler hours of the day to improve their effectiveness.
As part of the control measures, farmers have been advised to install one light trap per acre between 7 p.m. and 11 p.m. to attract and eliminate adult moths before they lay eggs. Chemical control has been recommended only in severe cases. Officials advised targeted spraying on the silken webs beneath the fronds using approved insecticides such as Dichlorvos or formulations containing Malathion, Quinalphos or Phosphamidon at the prescribed dosage. As a preventive measure, farmers with plantations located within a three-kilometre radius of the affected villages have also been advised to proactively release parasitoids to minimise the risk of the infestation spreading further.