Coffee Berry Borer: What it is and what damages it causes

The Coffee Berry Borer or Coffee Borer Beetle (CBB) is an insect found around the world and prevalent in most coffee producing countries. It is among the most harmful pests to commercial coffee plantations and can attack 50-100% of berries on a farm if no control measures are applied.

Description

The CBB belongs to the genus Hypothenemus, which has more than 181 species and can be found not only in coffee but also in plants, fungi and even drawing boards and books.

Thankfully, only three of the 181+ species are known to be found in coffee plantations; Hypothenemus Hampei Ferrari, Hypothenemus Seriatus and Hypothenemus Obscurus. All three pieces are known for feeding on coffee cherry, but only Hypothenemus Hampei Ferrari (H Hampei) will feed on the actual seed; potentially damaging the quality and quantity of the harvested crop.

H Hampei are quite tiny, typically ranging in sizes between 1.2 to 1.8 mm. H Hampei are also known for their super strong mandibles that enable them to bore the berries outer skin and make it their new home!

This type of beetle is the only animal that can feed solely on coffee beans. Other insects may occasionally nibble the seeds or other parts of the coffee plant but will need to eat other vegetation for sustenance.

Colonisation

The CBB will usually enter the coffee cherry when the water content is 20% or higher and the cherries are still green. This is about 120-150 days after flowering and 30 – 150 days before harvesting. 

Female H Hampei, known for being larger than their male counterparts as well as able to fly, are the ones to bore into the coffee fruit. This normally involves the Female H Hampei boring a 1mm in diameter hole through the very tip of the cherry, taking on average a little over 4 hours.

Once the female is inside, the beetle builds ‘galleries’, where she will lay between 35 to 50 eggs, two days after entering the cherry. The sex ratio of the CBB is very skewed, and the female beetle will produce 13 female eggs to every male.

After around 25 to 45 days depending on the weather, the first few stages of the beetle’s life cycle are complete and the insects will be fully developed. The new adult beetles will mate with their siblings and reproduce, resulting in even more beetles. In plantations with severe infestations of coffee borer, up to 100 beetles can be found inside a single fruit. These new generations can colonise neighbouring fruits and plants, spreading the infestation quickly. 

The male CBB will never leave the bean as his sole role is to reproduce. As such, 3 to 5 different generations of beetles can be found in a single tree, from one original female that first arrived at the plant. 

The usual lifespan of the females is around 35 - 190 days, with males lasting just 40 days. Reproduction may continue even in dry fruits, black fruits, overripe fruits and even in the ones that have fallen from the trees.

 Damage

The CBB is a very harmful pest, with the main damage caused to the fruit. This can result in the falling of the fruits from the trees, as well as losses in the weight and quality of the seed/beans, destroying the marketable product. 

The beans affected do not have the standard of quality needed for specialty coffee. Thus, these end up classified as second-class, which are difficult to market and are sold for second-grade coffee preparations. 

Additional damage comes in the form of higher costs of production, as farmers need to invest more time and money during picking and selection at the washing station, separating out the lower quality fruits. 

Cherry’s destroyed by the CBB will mean less coffee for producers to sell at a regular or higher price. Not only that but paired with the cost of implementing pest control measures (estimated to cost between 5-11% of a farm’s income), results in an extremely pricey problem.

So, what do the farmers do to keep the CBB at bay?

Prevention

One of the most common ways to control the spreading of CBB is by doing preventive pickings towards the end of the harvest. This means that picking is done in such a way that no fruits are left in the trees or on the ground, regardless of their level of maturity. 

By nature, these are second-grade fruits that will then be sold as lower quality coffee.

Unattended plants are a big focus for infestation. It is advised that those are pruned if the owner can't look after them. 

Credit: Neil Palmer CIAT

Control

The fight against the CBB is carried out on a number of different fronts. The cheapest is the aforementioned control, which in theory keeps the problem from happening or spreading in the first place. But once the insect is in the plantation, it needs to be eliminated and this can be easier said than done. 

The most common ways to eradicate CBB are:

Chemical control via insecticides. These are useful before the females enter the berries. But some of the substances used have been banned in many countries. 

Biological control. This involves using natural enemies of the CBB to reduce the population. This may include parasites, diseases or predators such as birds and even ants.

Nematodes. These are worm parasites in animals or plants. These have been shown to infect the CBB and to greatly reduce the population. 

Traps. In countries such as Colombia, traps are made from empty plastic bottles and can be found around the plantations where there is a presence of CBB. These accomplish 2 main things: one is to help estimate the level of infestation and the other is to kill the insects. They are placed every 10 trees or so and reviewed periodically. Traps are often containers with a big hole, filled with foamy water. Alcohol in a little pouch is used as bait, as it seems like it is really alcohol that attracts the beetles to berries when it is produced during the maturation process. 

Theoretically, it may be possible to develop a forecasting model to predict the upsurges of H. Hampei. Some studies have shown that the CBB is extremely sensitive in low humidity’s. It has been found that in certain conditions, after a long dry spell, large populations of beetles build up in fallen berries. Once the humidity has heightened (usually after early rains), the CBB are sparked to emerge. This is believed to increase the CBB chances of finding a new berry and avoiding desiccation. 

It seems like the best chance for the producers is to regularly monitor the berries and plantations, with the labour cost that might come with it.  However, more research is required to understand more about the CBB, in order to aid farmers in forecasting potential upsurges and tackle infestations in a cost-effective manner, as it doesn't seem like CBB is going anywhere any time soon.