The coffee berry borer is the worst insect pest in coffee cultivation. Known as Broca in Spanish, Hypothenemus hampei in Latin, and Coffee Berry Borer (CBB) in English, this beetle is responsible for annual damages exceeding 500 million US dollars (Infante, 2018). While this may sound abstract, it concretely means the loss of large parts of the harvest, which repeatedly affects small-scale producers in particular. The coffee berry borer bores into a coffee fruit, reproduces there, and destroys the coffee bean from the inside.
In this article, we report on how the coffee berry borer reproduces, what measures can be taken, and the damage it causes.
Living in the Coffee Bean
There are these guests who never leave the café. They are the first ones there in the morning, occupy a spot with their laptop, and type away until evening. They drink two large latte macchiatos spread throughout the day. The coffee berry borer is extreme in two ways. It lives entirely within the coffee bean and only leaves it, if at all, to fly to the next corner. To make matters worse, the industrious little pest reproduces on-site. It doesn't just drink two coffee beverages; in the end, the coffee bean is completely eaten out from the inside.
Among coffee berry borers, the females clearly call the shots. They preferentially bore into developing green coffee cherries starting 120 days after flowering. The entry point is usually the end opposite the stem. With her ovipositor, the insect lays up to 3 eggs per day for over 20 days. After a rest period, the process starts again. Up to 120 eggs are laid in this way by a female coffee berry borer.
The mother borer and her active offspring completely consume the cherry kernel. Once grown, the offspring happily continue to reproduce among themselves. While the male counterparts never leave the cherry, the young females soon set off for the next orgy. The relocation occurs when the old cherry no longer offers substance for eating and reproduction. The coffee berry borer covers distances of up to 500 meters by flight.
Distribution and Activities
Originating from Central Africa, the coffee berry borer is now found worldwide in almost all coffee-growing countries. In 1908, it was discovered in Indonesia and later in Brazil. From there, it spread throughout South and Central America.
Studies show that the coffee berry borer spreads particularly well in lower altitudes. The infestation of individual trees is stronger here, as is the general density of infestation. The same study also found that the spread in planted coffee plantations is much higher than, for example, in wild gardens with less dense vegetation.
The spread of coffee berry borers is also more pronounced in shaded plantations, as the insect prefers certain humidity. On the other hand, in this climate, the natural enemy and fungus Beauveria Bassiana also grows better, which acts as a natural insecticide.
Cherries left on the tree or those that fall to the ground are a breeding ground for the spread of the coffee berry borer.
Coffee Berry Borer Control
Many factors play a role in controlling the coffee berry borer. Especially important are planting density, climate, and farm management. To effectively combat the coffee berry borer, the annual cycle, particularly flowering, cherry development, and harvesting methods, must also be carefully considered.
Various methods are suitable for control. Ethanol traps are useful for attracting and catching coffee berry borers. The alcohol in a cut-open plastic bottle tricks the coffee berry borers into thinking coffee cherries are at a certain stage of ripeness. But instead of a feast, the coffee berry borers face a blackout without a happy ending. However, the traps are less suitable for effectively decimating coffee berry borer infestation. They are better suited for assessing the actual extent of the spread (extrapolated).
The most important tool for controlling a coffee berry borer infestation is the regular harvesting of unripe, overripe, and dried coffee cherries before the main harvest begins. These selective tasks are labor-intensive and correspondingly costly but essential for ensuring the quality of the harvest.
The endophytic fungus Beauveria Bassiana is a natural and organic agent
for the effective control of coffee berry borers. By targeted application to affected plants, the coffee berry borers are parasitized and killed internally.
In addition to the fungus, there are several natural enemies of the coffee berry borer, such as other parasitic insects. These include the African native colleague Cephalonomia stephanoderis.
For the final quality of the coffee, the stage at which intervention occurs is crucial. If the coffee berry borer is stopped before reproduction in the cherry, the sensory impact is minimal. A single visual sting is not considered a severe defect even in the physical evaluation of green coffee, and the coffee can still be specialty coffee.
Multiple stings and the loss of a larger mass affect the roasting of the coffee as well as its aging. If multiple stings are present, the sensory quality of a coffee is also extremely compromised.
Hawaii Starts Wasp Experiment Against Coffee Berry Borer
In an innovative approach to combat the coffee berry borer (CBB), a destructive insect threatening coffee plantations on the Hawaiian islands, researchers are now deploying the wasp Phymastichus coffea. This tiny insect, barely visible to the naked eye, could be the solution that Hawaii's coffee farmers have been waiting for.
Phymastichus coffea is a parasitoid - an organism that ultimately kills its host (in this case, the coffee berry borer). The wasp uses the coffee berry borer as a host for its larvae. This specific type of biological pest control has already proven successful in Central and South America, particularly in Colombia.
Since 2018, live specimens of the wasp have been allowed into Hawaii under strict quarantine conditions. Researchers have extensively tested the wasp to ensure it has no negative impacts on native insect species. Tests have confirmed that P. coffea does not attack native insects and even shows potential parasitic activity against the Tropical Nut Borer, another pest threatening macadamia nuts.
Researchers now plan to release thousands of these wasps into coffee-growing regions throughout Hawaii. The wasps are expected to establish themselves in the wild and maintain their populations independently. They will be released on Big Island and possibly on Maui and Oʻahu in the coming months.
Similar approaches have already been attempted in Colombia and other countries. A research project published in the Journal of Pest Science indicates that the wasp primarily parasitizes the desired coffee berry borer and not more distantly related species.
Conclusion on the Coffee Berry Borer
Once again, the tragedy is that the coffee berry borer is a challenge that can be effectively combated with financial resources on the farm and the necessary knowledge. Unfortunately, the former is often not available, which leads to completely unnecessary losses of quality and entire harvests.
Controlling the coffee berry borer is one of the simplest measures to broadly improve the quality of the coffee harvest. Particularly noteworthy: organic measures and targeted farm management are just as effective and much cheaper than synthetic agents.
Sources and Further Reading
More about the Coffee Berry Borer, MDPI
Pest Management Strategies Against the Coffee Berry Borer, Journal of Agricultural and Food Chemistry
Biological control of the coffee berry borer: Main natural enemies, control success, and landscape influence, Science Direct
Vega, F. E., Infante, F. & Johnson, A. J. The genus Hypothenemus, with emphasis on H. hampei, the coffee berry borer in Bark Beetles: Biology and Ecology of Native and Invasive Species (eds Vega, F. E. & Hofstetter, R. W.) 427–494 (Academic Press 2015). Google Scholar
Observing the devastating coffee berry borer (Hypothenemus hampei) inside the coffee berry using micro-computed tomography, Nature
Damon A. A review of the biology and control of the coffee berry borer, Hypothenemus hampei(Coleoptera: Scolytidae) Bull. Entomol. Res. 2000;90:453–465. doi: 10.1017/S0007485300000584.<PubMed> <CrossRef> <Google Scholar>
