Time for coffee and tea
Coffee tree pests
There are many pests that have an impact upon the growth of Arabica trees, these include birds, mammals, worms and mites, but the coffee tree pests that have the greatest impact on coffee production are insects. It is estimated that at least 900 different species of insects feast upon the coffee tree. In most countries these pests are controlled by insecticides, however, in the Ethiopian highlands, where coffee Arabica evolved there is a natural equilibrium between coffee pests and their predators making it very rare that insects and other pests spread to epidemic proportions.
Many beetles lay their eggs in the bark of the Arabica coffee tree, once these hatch the larvae bore and cause havoc to the tree. Perhaps the most serious coffee tree pest is the white borer. The larvae of this beetle bore into the taproot of the coffee plant and work their way up the stem, emerging approximately a year and a half later.
Without chemical intervention the white borer causes havoc on coffee trees in Eastern African countries; it is controlled by applying a solution of 0.05% dieldrin to the base of the stem. Another major pest in East Africa is the yellow-headed borer, with this beetle the eggs are laid on primary branches as opposed to the base of the stem (white borer). The larvae then eat their way down the branch and into the stem, where they eject the frass and create large exits. These pests can again be controlled by the use of dieldrin solution; in this case the solution is applied through the lowest frass hole.
In addition to beetles many moth larvae are also pests of the Arabica coffee tree, these generally enter through the green shoots near the tips of the coffee tree and bore themselves down the shoot, this results in wilting of the tips.
Other pests of stems and branches are mealybugs and scales; these are able to attack mature wood. The Star scale is actually capable of destroying mature coffee trees!
One of the most efficient ways of controlling scales and mealybugs is by use of biological control. The mealybug once devastated Kenyan coffee plantations but was able to be controlled by the introduction of Anagyrus kivuensis, its natural predator from Uganda . Another way of controlling these pests is by growing small bushes along road verges, this helps in preventing the spread of dust; Asterocalanium coffeae thrive in dusty environments.