Black Head Caterpillar has severely affected the coconut yield in Krishna district. Thousands of coconut trees in north-east Krishna are affected by this pest and the infested trees have a burnt look with most of the mature leaves getting reduced to dead brown tissue. Only a few young leaves remain.
Besides regular coconut groves, coconut is cultivated on a large-scale on the bunds of the fish tanks as a secondary source of income. “The infestation has come from nowhere and the coconut yield has come down by 50 per cent,” said V. Ranga Rao who has lined his aquaculture tank on the Kaikaluru-Eluru Road with coconut trees.
Horticulture Assistant Director R. Rama Mohan told The Hindu that the only permanent solution to the infestation was biological control. This was done by releasing the natural enemies of the leaf-eating caterpillar on a large scale. Packets of larval parasites (cocoons) were available at the Agricultural Research Centre at Ambajipet in East Godavari District.
The natural enemy of the leaf eating caterpillar, a wasp, stings and paralyses it. The wasp then sucks on the juices in the caterpillar. Later it lays eggs in the body of the paralysed and dying caterpillar. The young caterpillars of the wasp on hatching feed on the leaf eating caterpillar.
The infested leaves should be pulled down and burnt and in case there was fresh infestation the farmers should go for ‘root-feeding’ of monocrotophos, Mr. Ram Mohan said. Root-feeding was done by cutting a root of the coconut tree and immersing it in a polythene bag of moncrotophos solution.
The pesticide was absorbed by the tree and the caterpillar which eat the leaves with the pesticide die. This was preferred because it was not practical to spray full grown coconut trees, Mr. Rama Mohan said. The Black Headed Caterpillar was a major problem in Sri Lanka destroying huge tracks of coconut.