MAJOR COFFEE INSECT PESTS IN THE HIGHLANDS OF NORTHERN THAILAND AND THEIR CONTROL

Abstract

It was noted that there were approximately five species of important insect pests of coffee in the highlands of northern Thailand. Refering to their nature of damages, they could be divided into two groups. The first group was classified as the small sucking type insects such as aphids, mealy bugs, and green scale. They normally prefer to attack the newly grown coffee seedling or young coffee plant about one to two years old after transplanting. These insects apparently suck the nutrients from the young shoots and leaves, thus deforming the leaves and retarding the growth process. Moreover, they also secrete the honeydew which become the source of food for black mold coated on the leaves, thus interfering the photosynthetic process. Another group comprised of stem borers such as red coffee borers and long horn coffee stem borers. These borers are considered to cause the serious damage on fully grown coffee plant, about four to five years old. The damage from them usually causing the plant to wilt and die later. The control measures of these two groups of insects are often end up with the use of insecticides. In the highland areas, if the insecticides are more frequently used, the highly precaution should be considered. It is due to the chemical residue which might contaminate the water in the streams and could cause harmful to human and animals in the lowland areas. The recommendation for thechemical control when necessary is to select the short residue insecticide with low toxicity to human and animals and spray only inside the outbreak avoided. In addition, the cultural control could also minimize the population of insect pests.