Tiny bark beetle threatens coffee industry across the state

Hawaii is the only state in the United States where coffee is grown commercially, and Hawaiian coffee, often synonymous with Kona, is beloved throughout the world. Coffee farms have started springing up on Maui in recent years. “There are maybe 20 times more coffee farmers than 10 years ago,” said Sydney Smith, owner of Maliko Estate Coffee and president of the Maui Coffee Association.

But a tiny bark beetle from Africa, Hypothenemus hampei, or coffee berry borer, threatens the coffee industry throughout the state. The miniscule pest was first detected in Kona in 2010. It spread like wildfire reaching north Kona, Kau, Hawi and Hilo. The beetle lays eggs inside of coffee berries. Its larvae hatch and begin to feed, hollowing out the bean and leaving little to harvest and roast.

“Once infestation levels exceed 50 percent of the cherries in the field, the coffee is not worth picking,” said Rob Curtiss, an entomologist with the state Department of Agriculture. He explained that there are farms on Hawaii Island with 80 to 90 percent infestation. “After (the beetles) are in the coffee (fruit) there is nothing you can do to kill them.”

People are responsible for spreading coffee berry borers, Curtiss said. Moving infested beans and bags moves the insects. A few infested beans in the back of a pickup truck could mean the introduction of the pest to a new farm – where the beetle population then explodes. Each female can lay 120 eggs, of which there are 10 females for every male. When the females mature, they find a new coffee fruit, tunnel inside and lay eggs immediately. Their life cycle is approximately 27 days, most of which occurs inside the coffee berry. “Every 30 or so days you can multiply the infestation by about 80,” Curtiss said. “In four months’ time one beetle becomes 40,960,000 beetles.”

Coffee farmers in Kona have been working closely with entomologists and researchers at the Agriculture Department and the University of Hawaii-College of Tropical Agriculture and Human Resources to find effective ways to manage the infestation.

By combining several methods of control, some farmers on Hawaii Island have successfully reduced infestation levels to below 5 percent. This system of integrated pest management includes protocols for field sanitation, pruning, monitoring, pesticide application, harvest and shipping. Instructions can be found in an online publication on the university’s Tropical Agriculture College website titled “Recommendations for Coffee Berry Borer Integrated Pest Management in Hawai’i 2013.”

The long-term solution may lie in the discovery of an effective predator for the beetle. According to Curtiss, coffee berry borer is an ongoing target for biocontrol research for the state Department of Agriculture. The department’s exploratory entomologist may someday make a promising discovery in Africa, the beetle’s native range.

Currently, an interisland quarantine restricts the movement of coffee plants and unroasted or untreated “green” coffee from the Big Island to prevent the pest’s spread to other islands.

Back on Maui, Sydney Smith has changed the way she runs her farm.

“I used to give tours to visitors, but I don’t do that anymore . . . I’ve removed coffee plants from near our vacation rental.”

Smith’s actions stem from concerns that a visitor may have toured an infested coffee farm on Hawaii island and may unknowingly be transporting a beetle. “They’re little tiny things that can get in shoes and clothes,” she said.

The coffee berry borer has thus far only been detected on the Big Island, but Maui coffee farmers have been trained on what to look for. “It’s not if – it’s when,” Smith said.

To learn more about coffee berry borer, visit www.ctahr.hawaii.edu/site/cbb.aspx and hdoa.hawaii.gov/pi/ppc/coffee-berry-borer-information-page.

* Lissa Fox Strohecker is the public relations and education specialist for the Maui Invasive Species Committee. She holds a biological sciences degree from Montana State University. Kia’i Moku, “Guarding the Island,” is prepared by the Maui Invasive Species Committee to provide information on protecting the island from invasive plants and animals that can threaten the island’s environment, economy and quality of life.