Alternatives for controlling the coffee borer

The coffee borer is one of the main pests of coffee plants in Rondônia. It causes severe damage, such as rotting of grains and falling of boring fruits, loss of weight and quality in processed coffee, limitation of coffee seed production, depreciation of the product in classification and loss of external consumer market. In recent years, there has been a dilemma regarding pest control with insecticides. It all started with the ban on the use of Endosulfan, considered highly toxic to humans. Of the insecticides registered for coffee cultivation, Endosulfam, until its prohibition in Rondônia, was the only active ingredient known to be effective in controlling the coffee borer. In addition, there was only registration of some products containing the active ingredient Chlorpyrifos, the limitation of which is its efficiency in the field, considered only average (51 to 79% of control), according to the classification for this purpose. 

Only from 2016 onwards were registered by the Ministry of Agriculture, Livestock and Supply Mapa, new insecticides for this pest such as those based on Ciantraniliprole, in addition to the inclusion of alternatives for biological control methods (beauveria bassiana) and mechanical (trap with Ethanol + Methanol), as listed in Table 1. It is worth remembering that the fact that a product is registered does not mean that it is highly effective against the target pest. The new products are relatively expensive compared to Endosulfan and there is still no proof that they are efficient in all coffee producing areas and regions, as is the case in Rondônia. These new products are less toxic and harmful to the environment, especially those in classes IV and III described in Table 1.

Table 1. Products registered for coffee borer (Hypothenemus hampei)

How to control the drill

The most appropriate way to monitor the borer infestation and carry out control at the appropriate time is to carry out monthly sampling of the crop. It is recommended to start when the fruits are in the lead and lead phase (November to January), a period in which the seeds are already formed, being the phase in which the borer pierces the fruit and can lay eggs. To carry out sampling in the field, you must go through the plot in a zig-zag pattern and take 20 fruits from each plant chosen at random (five on each side of the plant). The number of plants to be sampled depends on the size of the plot. For a plot with 1.000 plants, at least 30 plants are sampled; plot with 1.000 to 3.000 plants, 50 plants must be sampled; if the plot has 3.000 to 5.000 plants, sample 75; and above 5.000, 1,5% of the plants must be sampled. The fruits from each plot will form a single sample. Next, the brocaded and non-broached fruits are separated to determine the percentage of infestation. In practical terms, the result will be obtained by multiplying the number of brocaded fruits by 100 and dividing this result by the total number of fruits in the sample. 

Chemical control must be started when the percentage of bored fruits is equal to or greater than 3%. It must be carried out in the most attacked parts of the crop. As the attack is not distributed evenly, control is recommended only for plots whose pest infestation has already reached 3%. This procedure avoids unnecessary expenses with labor and insecticides, and impacts related to the use of agrochemicals are reduced. Even after control, monitoring must continue and, if the infestation reaches the control level again, a new application must be made, respecting the insecticide deficiency limits. Reducing borer attack in the following harvest can be achieved by harvesting well in the current year. As well as carrying out the transfer in the field, to prevent the pest from surviving in the fruits left on the coffee trees or fallen on the ground. Old and abandoned coffee plantations, in which the borer finds shelter and multiplies freely, must be destroyed. It is important to raise awareness among neighbors so that borer control can be carried out, preventing the spread of outbreaks to other crops.  

Biological control

It was observed, in crops in several municipalities in Rondônia, the occurrence of a fungus called beauveria bassiana naturally providing biological control of the borer. It is easy to notice the presence of the fungus, which closes the hole made by the drill in the form of a white tuft. It is common to find the fungus surrounding a dead borer at the entrance to the hole, meaning that the borer died from being infected by it before reaching the seed.  

In crops where the fungus occurs, it is recommended not to apply agrochemicals, unless the borer infestation exceeds 3% of the borer fruits without infection. B. bassiana. Biological products based on the fungus are registered. The use of biological components in the formulation of pesticides or fertilizers is growing significantly. It responds to a demand from society to restrict and expand care in the handling and use of chemical components and also to significantly advance research in the sector. Commercial products registered for coffee borer based on beauveria bassiana are listed in Table 1.