Coffee borer management

Pest responsible for serious damage to coffee productivity and quality, the borer hypothenemus hampei continues to challenge Brazilian producers. Its management involves monitoring, adequate cultural control and correct application of insecticides.

The coffee borer, hypothenemus hampei (Ferrari, 1867) (Coleoptera: Curculionidae, Scolytinae), is currently, for most coffee growing regions in Brazil, the second most important pest of the coffee plant Coffea spp. Known in the country since 1922, and until 1970 considered the main pest of coffee plants, it became the second or even third in importance in most of the country's coffee growing regions, with the exception of Zona da Mata in Minas Gerais, states of Espírito Santo and Rondônia. , and also from crops very close to large dams, in any region, due to the high humidity and temperature conditions in these locations, ideal conditions for the insect's development and survival in the off-season.

The borer is an important pest in irrigated coffee farming, due to its greater survival in the off-season, in the moist fruits remaining from the harvest and which remain on the plants or on the soil. The adult female insect is a small, black, shiny beetle, measuring approximately 1,7 mm in length and 0,7 mm in width.

The male is smaller and approximately 1,2mm long by 0,5mm wide. It does not fly (hind wings are atrophied) and constantly remains inside the fruits where female copulation and fertilization take place.

The females pierce the fruits, from green (chumbões) to ripe (cherries) or dry (raisins), generally in the crown region, digging a gallery with around 1mm in diameter until reaching the seed. 

In the evolutionary cycle of the drill, male development is faster (two larval instars) than female development (three larval instars) (Figure 1).

DAMAGE CAUSED

The attack of the coffee borer, H. hampei, causes the fruit to fall, reduce the weight of the beans (quantitative loss) and reduce the quality of the coffee through changes in the type and sometimes the drink itself (qualitative damage). The damage is caused by the insect larvae, which live inside the coffee fruit, generally attacking a single seed, and rarely both, for food. The destruction of the fruit can be partial or total. 

Initially, losses are caused by falling fruit. For Coffea arabica L., it has already been found that the borer increases the percentage of natural fruit drop of around 8% to 13% and for Coffea canephora Pierre & Froehner (Conilon) the insect may be responsible for a fruit drop of approximately 46%, as it is more susceptible to borer attack. The broached fruits that remain on the plants suffer weight reduction, and it has already been experimentally demonstrated, in Minas Gerais, that these losses can reach 21% or 12,6kg per 60kg bag of processed coffee. It was also found that the quality of the coffee is altered by the borer attack, going from type 2 to type 7 only with the increase in pest infestation, as two to five bored beans constitute a defect. Losses increase during the shelling operation due to the fragility that the attacked grain becomes, being broken and discarded with the ventilation of the shelling machine. The damage caused by the borer begins when the infestation reaches 7% to 10% in the fruits of the largest bloom. The quality of the coffee drink is not directly influenced by the borer attack, but rather indirectly by the ease that the damage provides for the penetration of microorganisms, such as fungi of the genus Fusarium e Penicillium, which are related to changes in the quality of the coffee drink.

DRILL MONITORING

In order for control to begin at the correct time, periodic sampling of the fruits (borer monitoring) must be carried out in the different plots of the crop, starting with the lowest and most humid parts.

Borer monitoring must begin during the insect's “transit” period, from November to January, approximately three months after the major flowering (October), when the first borked fruits are observed in the rosettes, and carried out until April. At this time, the adult females of the insect abandon the remaining fruits from the previous harvest (fruits found in the off-season) where they bred, fly and pierce developed green fruits (leads) from the following harvest, without even laying eggs immediately after piercing them, which they do. approximately 50 days later. Between November and January the fruits are very watery, with more than 80% moisture, not yet an ideal food for the insect larvae.

CONTROL METHODS

cultural control cIt is perhaps the most efficient method of combating the coffee borer. Coffee plantations must be planted at spacings that allow greater aeration and light penetration, in order to provide low air humidity inside, conditions that are unfavorable to the pest, in addition to allowing the circulation of sprayers attached to tractors.

Even more important is that the coffee harvest must be carried out in such a way as to prevent fruit from remaining on the plants and on the ground and the borer from surviving during the off-season (remaining fruit), especially if there is a large volume of rain. After harvesting, if there are a lot of grains left on the plants and on the ground, it is recommended to transfer or collect them. This method, already practiced in the early days of Brazilian coffee farming, needs to be considered again in the management of the coffee borer, due to the high costs and the lack of efficient products for its control.

Study carried out on a coffee tree of the species C. canephora cultivar Conilon, in Espírito Santo, showed, five months after harvest, that approximately 71,7% of the remaining fruits were attacked by the borer, which highlights the importance of a good harvest and transfer (collection of fruits that were not harvested). , especially in non-mechanized crops, where spraying is difficult to carry out. In Rondônia, also in Conilon, an average infestation of 76,3% has been found in fruits in the off-season and those that have fallen to the ground.

The harvest must always begin in the plots that have the most infested coffee trees, in order to avoid further damage, as the borer has a great capacity for reproduction and, in years of high infestation, the last plots to be harvested will, without a doubt, present , larger borer populations and consequently greater losses.

Conventional chemical control

In Brazilian coffee farming, greater spacing allows applications with sprayers coupled to tractors. In this case, chemical control of the borer is considered efficient and fast, unlike some producing countries that practice dense and/or shaded coffee cultivation.

There are few active ingredients registered in Brazil for use on coffee plants to control the coffee borer: [chlorpyrifos-ethyl 480 EC (organophosphate), etofenproxi 100 SC (diphenyl ether) and azadirachtin 12 EC (tetranortriterpenoid)].

The chemical control tactic is often the only one available to keep the pest below the control level of 3% to 5% of bored fruits. If possible, reach those where the drill has not reached the seed, where it will be killed by contact with the insecticide applied, before laying eggs.

As the attack is not distributed evenly across a crop, control is recommended only in plots where infestation has already reached more than 3% to 5% of the fruits. Therefore, most of the time, control is not carried out across the entire crop, but is limited to a few plots. In irrigated crops, chemical control may be necessary in most fields.

Agricultural research

Agricultural research in coffee growing in Brazil has always been attentive to seeking new methods of controlling the coffee borer, which includes chemical control, considered more efficient in controlling the pest.

In a survey carried out over 30 years of research into chemical control of the borer in Brazil, between 1973 and 2003, of 269 treatments surveyed, approximately 21% were carried out with endosulfan, whose efficiency ranged from 70% to 100%. This product is currently prohibited from being used to control any pest in Brazil. The other insecticides did not show equivalent efficiency to endosulfan. Although some showed promise, they were never registered for use in coffee farming due to environmental problems or high cost.

Subsequently, several molecules being tested for the control of the coffee borer have become prominent in the various coffee growing regions of Brazil. One of them is cyantraniliprole 10% OD (cyazypyr), with emergency registration in Brazil and called Benevia, an insecticide from the anthranilic diamide group developed in several countries by DuPont and which presents a new mode of action. It is a second generation (single action through the activation of ryanodine receptors), with a mode of action similar to chlorantraniliprole (altacor, rynaxypyr), another insecticide already in use in Brazil and registered for the control of leaf miner, Leucoptera coffeella (Guérin-Mènev. & Perrotet, 1842) (Lepidoptera: Lyonetiidae) in coffee trees.

Other active ingredients being tested, and already showing promising results in controlling the borer, are metaflumizone (Basf), etiprole (Bayer) and the mixtures chlorantraniliprole + abamectin (Syngenta) and imidaclopriod + bifenthrin (Adama).

Paulo Rebelles Reis, Epamig Sul de Minas/EcoCentro

Article published in issue 198 of Cultivar Grandes Culturas.