Coffee institute finds solution to white stem borer

Century-old pest problem has devastated Arabica plantations across Karnataka

The Central Coffee Research Institute (CCRI), Balehonnur, under the Coffee Board, claims to have achieved a major breakthrough in its research to find a solution for the deadly white stem borer pest that has devastated Arabica coffee plantations across growing regions in Karnataka.

In order to find a suitable solution to this problem, which is prevalent for over 100 years in coffee plantations, the CCRI has carried out a series of field trials during 2014 to find out ways and means of killing the stages of coffee stem borer within the affected plants so as to prevent spread of infestation. A few methods like stem injection and root feeding of systemic pesticides, coating with sealer cum healer, stem wrapping with insecticide treated material among others were tried.

In one such experiment, the infested plants showing typical symptoms (of ridges on main stem, yellowing and slight wilting) were marked and the main stem was wrapped using gunny bag strips. The gunny bag cover on main stem was sprayed with an insecticide formulation containing Chlorpyrifos 50EC + Cypermethrin 5EC at the dosage of 1.2ml/ litre of water along with 1 ml of a wetting agent. After the completion of the flight, the gunny wrapped plants were examined for status of the stem borer stages. It was observed that in almost all infested plants, the adult beetles were found to be dead at the tip of the emergence hole, CCRI said in a statement.

“This is for the first time it has been demonstrated successfully that the adult beetles of stem borer could be killed before their emergence! If the adult beetles are prevented from emergence, then there is immense possibility of reducing the stem borer infestation levels to insignificant levels within quick time,” Jawaid Akhtar, Chairman, Coffee Board said in a statement.

One of the major factors for increased incidence of stem borer is retention of infested plants in the field especially during the post monsoon flight period (October-December), since such plants will have some fruits and the growers are reluctant to lose the crop. Growers postpone the removal of such affected plants till the end of harvesting (January), by which time the adult beetles of stem borer would have emerged and laid eggs on nearby healthy plants.

Plantations spread over 3,000 hectares in Karnataka affected by the pest in 2014. Karnataka produces 70 per cent of the country’s coffee. In view of the very encouraging results in the preliminary trials, the CCRI has planned elaborate multi-location field trails during the pre-monsoon flight season of this year (April-May 2015) to validate the results on a large scale.

The coffee growers may try this method on their fields on a limited area to quickly validate the results in their estates, the CCRI said.

The above method of treating the infested plants should be completed before as soon as possible preferably before end of April and October months. By doing so it would be possible to drastically reduce the population of the stem borer beetles which would go a long way to gain control over this dreaded pest of Arabica coffee, the CCRI added.