Coffee Berry Borer: The Beetle Inside the Coffee Bean

The coffee berry borer is a tiny beetle, Hypothenemus hampei, that Wikipedia's summary of the research literature calls the most harmful insect pest of coffee worldwide. The female bores into a coffee cherry and lays her eggs inside the seed, the part that becomes the coffee bean, and the young feed on it from within. Because the whole cycle happens out of sight inside the fruit, the pest is hard to reach with sprays and easy to spread on harvested cherries. It affects the livelihoods of more than 20 million coffee-farming families. This guide explains how the coffee berry borer lives and spreads, the damage it causes, how farms in Hawaii and Jamaica fight it, and what it means for coffee quality.

What is the coffee berry borer?

The coffee berry borer is a small bark beetle native to central Africa. Females are about 1.4 to 1.8 mm long and males about 1.2 to 1.6 mm, according to Wikipedia's summary, so a single beetle is smaller than a sesame seed. It attacks both arabica and robusta. Only the females fly; males stay inside the berry where they hatched.

Life cycle: a beetle that lives inside the bean

1. Colonization. A mated female flies to a developing cherry and drills in, usually through the small disc at the tip of the fruit. Females attack fruit from about 8 to 32 weeks after flowering.
2. Egg laying. About two days later she begins laying eggs in a gallery inside the seed, typically 35 to 50 eggs.
3. Feeding. The larvae feed on the seed tissue. Development from egg to adult takes 24 to 45 days depending on the weather.
4. Mating inside the berry. Brothers and sisters mate inside the cherry. Females far outnumber males, so one infested cherry can produce many new egg-laying females.
5. Emergence. Mated females leave to find new cherries. A tree can host three to five generations in a season, with up to 100 beetles in a single fruit, and females can live from 35 to 190 days.

Cherries left on the tree or the ground after harvest are the beetle's refuge between seasons, which is why clearing them is the foundation of control.

How the berry borer spread around the world

What damage does it do?

The borer costs farmers twice, through losses in both yield and quality, according to Wikipedia's summary: the larvae consume part of the seed, and bored beans are defects that lower the grade and price of the coffee. Left uncontrolled, the beetle can infest up to 100% of berries at harvest, according to the 2017 review of Hawaii and Puerto Rico by Aristizabal and colleagues. The same review reports that high-grade Hawaii coffee was drastically affected in 2011-2013 and production costs rose by 10 to 15%. The University of the West Indies puts worldwide losses at more than 450 million euros a year. Our Kona coffee guide covers how the beetle changed farming there.

How farms control the coffee berry borer

No single method works, so farms combine several in an integrated pest management (IPM) program. The 2017 review of Hawaii and Puerto Rico recommends these steps:

1. Monitor. Use alcohol-baited traps and a regular sampling plan of about 30 trees to find hotspots and track flights.
2. Harvest thoroughly and on time. Pick ripe and overripe cherries often, so few are left for the beetle to breed in.
3. Strip-pick and sanitize after harvest. Remove every remaining cherry, green, ripe and dried, from the trees and the ground. In one trial cited by the review, farms that delayed strip-picking by about two months still had more than 100 beetles per trap per day into April.
4. Spray a biological control at the right time. The fungus Beauveria bassiana infects and kills the beetle. It works best when females are still boring into young berries, before they are sealed inside the seed. In Hawaii it was registered in 2011 and about 80% of the acreage on Hawaii Island and Oahu was treated over four years.
5. Contain it after harvest. Keep beetles from escaping processing areas and transport, for example with enclosed mills and sealed bags.
6. Prune in blocks. Stump-pruning whole blocks breaks the beetle's cycle; on one farm in the review, total defects were 3.9% against about 10% on traditionally pruned farms.

Natural enemies help too. Wikipedia's summary lists several parasitoid wasps used against the beetle and reports that insectivorous birds halved borer numbers in Costa Rican plantations, one of the benefits of keeping shade trees (see shade-grown coffee). Chemical insecticides are not considered a good option because of their cost and environmental effects, and resistance to one insecticide has been reported.

The berry borer in Jamaica and the Blue Mountains

The beetle was first detected in Jamaica in 1978, during processing of beans meant for export, according to Myrie and colleagues' 2023 study in Insects, and the University of the West Indies describes it as having threatened yields and quality ever since. The study monitored borer flights with homemade methanol-ethanol bottle traps on two farms over the 2016-2017 crop cycle: a High Mountain estate at about 567 m and a Blue Mountain farm at Rosehill, about 960 m. The traps caught 12,921 beetles on the Blue Mountain farm, with flights peaking in February at 129 beetles per trap per month, and berry infestation there peaked in October at about a third of berries. Rainfall, not temperature or humidity, had a significant relationship with beetle activity. No chemical control was used at either site during the study, and the authors noted that chemical control has traditionally been Jamaica's main approach, with a shift toward more sustainable methods over the past 20 years.

Research is continuing. In 2024 researchers from UWI Mona and German universities sequenced the beetle's genome and compared populations from farms across Jamaica. As UWI reported in 2025, they found low genetic diversity, suggesting a recent population bottleneck, and hope to use the results to target control more precisely and reduce pesticide use. For more on the region's farming conditions, see the Blue Mountain growing area; for the island's other major threat, see coffee leaf rust.

Does the berry borer affect coffee quality?

Yes. Bored beans are counted as defects in green coffee grading, and enough of them shows up in the cup: the University of Hawaii's extension service (CTAHR) says unmanaged borer damage of 10 to 15% is detectable in professional cupping. That is why sorting matters so much on affected farms (see how to cup coffee and Jamaica Blue Mountain grades). For drinkers, the practical signs are a clean, well-sorted bag of whole beans without small round holes, and a supplier who can say where the coffee was grown and how it was graded.

Disclosure: this site is published by Mamre Blue Coffee, a Jamaica Blue Mountain estate (see about us), so we rely on official and independent sources for the facts on this page.