MANAGEMENT OF COFFEE BERRY BORER

The infestation of coffee fruits by the berry borer is becoming a cause for concern in most of the coffee growing areas as the crop harvest is either in progress or it is approaching. This year, due to the unexpected early and heavy showers during February and March in most of the coffee growing areas, there was a considerable delay in harvesting of robusta coffee and quite a good proportion of the ripe infested fruits had fallen. The delay in harvest resulted in more generations of the borer multiplying in the field. The availability of the fruits on the field for a longer period permitted the borers to continue breeding and spread to more areas.

The untimely rains during last year, coupled with non availability of sufficient work force, prevented thorough collection of gleanings and left-over fruits. The effect of this is now being observed on the current crop with early fruit ripening, in terms of increased incidence.

The female coffee berry borer bores into young as well as ripe berries generally through the navel (tip) region. But tunneling and egg laying are only possible in berries where the endosperm has hardened. On an average around fifty eggs are laid in the tunnel within a mature bean. The eggs hatch in 5-9 days. The grubs feed on the beans, making small tunnels. Complete development from egg to adult takes place in about thirty days. The fertilized female leaves the parent tunnel and bores into a fresh fruit for oviposition (egg laying). The average longevity of the female is 156 days, which is sufficient to enable the pest to carry over from one season’s crop to the next, under Indian conditions. Thirty to eighty per cent of the fruits may be attacked if the infestation is severe, resulting in heavy crop loss. Generally only one of the beans in a berry is affected, though damage to both the beans is observed in case of severe infestation. Though the beetles are active in the field now, the catch in the broca traps is low because the beetles tend to be attracted to the fruits present on the coffee plants. Wherever arabica is interplanted with robusta or is grown as a separate plot in close proximity with robusta, the berry borer is in an advantageous position as the coffee fruits of the right maturity are available for a longer period. For example, arabica berries mature early and the berry borers start a new life cycle on them as soon as the endosperm hardens. By the time a new generation emerges in about thirty days time, the endosperm in the robusta berries also would have developed to the consistency preferred by the borers to make tunnels and multiply. In such plots or areas, it is preferable not to delay the harvest. If harvest is delayed, the berry borer can complete more generations on the fruits and the effect on the crop, particularly robusta coffee, would be severe. In Arabica plots close to robusta, berry borer traps @ 27 per acre (40 feet spacing) may be installed after harvest so that migration to robusta can be minimized.

To prevent the escape of beetles back to the estate, the coffee harvested from infested blocks may be dipped, along with the gunny bag, in boiling water for two minutes and then taken to the drying yard/pulper. Alternatively, polythene sheets smeared with a vegetable oil may be placed above the coffee while drying, for three to four days, and the trapped beetles destroyed. Berry borer traps may also be installed around the drying yard while coffee is being dried.

Given these conditions, it is imperative that all phyto-sanitary measures are adopted while harvesting. Thorough and complete harvesting should be done and picking mats should be used to reduce gleanings. After the major harvest, special care should be taken to remove the left over fruits on the plants as well as from the ground as these will form the major source of borer inoculum of the next season’s crop.