Coimbatore, April 2. (PTI): The Institute of Forest Genetics and Tree Breeding (IFGTB) has warned of a 'severe attack' of a tiny pest in all eucalyptus growing areas, which would spread fast to newer areas if left unattended.

Eucalyptus is a rather hardy species and is affected only by a few insect pests in India. Recently a severe attack by a new invasive gall insect was noticed by the Andhra Pradesh Forest Development Corporation, which was referred to the IFGTB here, its Director, Dr M Surya Prakash said.

After observation, scientists at IFGTB found that the insect is 'Leptocybe invasa,' a wasp measuring 1.1 to 1.4 MM, Surya Prakash said.

Though the pest is presumed to have originated from Australia, its occurrence was reported in 2000 from the Middle East. Subsequently it has spread to most Mediterranean countries and Northern and Eastern Africa.

In India, it was first noticed in 2002 at Marakkanam in Villupuram District in Tamil Nadu. It was restricted to a small pocket and was not observed to be serious.

The attack assumes greater significance since it has spread to other parts of India. An extensive survey by IFGTB in Tamil Nadu, Andhra Pradesh, Kerala and Puducherry in February-March 2007 revealed that the pest is spreading to newer areas and if left unattended, may become severe in all eucalyptus growing areas, Surya Prakash said.

Adult wasps lay eggs inside tender leaves and stem. The larvae after hatching, remain in a cavity formed within the plant tissues and feed on the plant sap. The injury to plant tissues results in formation of galls.

The pest attack was observed in nurseries, coppice shots and young plantations, with the affected seedling showing stunted growth and becoming unsuitable for planting, Surya Prakash said.

The attack was observed in the plantations of one to two years of age, leading to reduced vigor and drooping of branches. The problems needs to be addressed on priority as it may lead to heavy economic loss to farmers and other planting agencies.

Eucalyptus is an important pulpwood species, widely used as raw material in the paper and rayon industry in India, with pulp and paper mills and forest development corporations embarking on raising the plantations on a large-scale.

Several farmers are also taking up this plantation and it is estimated that about 80 lakh hectares are under eucalyptus cultivation in India, Surya Prakash said.

The present yield in eucalyptus clonal plantations ranges from 70-100 MT/HA on a five-year rotation. The current buying price of wood is Rs 2000 per ton at the felling site.

As interim measures to manage the pest, periodic monitoring of the infestations in nurseries and plantations should be adopted, mechanically remove the severely affected plants, parts and burning, avoid production, planting of highly susceptible clones and application of systemic insecticides.

To discuss and decide on the future course of action, leading entomologists from various research Institutes from India would meet here from April 10 to 13, Surya Prakash said.