Coffee farmers, who face the removal this year of the main pesticide used to kill berry borers in coffee, are managing to reduce the borers by up to 60 per cent by destroying the fallen berries that the pests live in between seasons.
The coffee berry borer (CBB) is the most important pest for all coffee growers worldwide. According to CABI, the CBB causes yield losses of up to 80 per cent to farmers in Kenya. Studies have shown that one coffee berry on the ground infested with CBB infected around 590 more berries on coffee trees. Rising temperatures– 2023 was recorded as the world’s hottest year– are making it easier for the pest to destroy coffee in Kenya’s highlands where it previously was not able to survive while increasing the number of times it can reproduce from 1-4.5 to 7.5 -13.5 times every year.
In 2023, Collins Kimanthi a coffee farmer in Embu lost his entire harvest (12 tons) from his one and a half acres to CBB. To keep the burrowing pest from running him out of business he has had to invest in costlier but more effective pesticides. “While the general-use insecticides cost Sh1,500-2500 a liter they are not as effective in clearing CBB. This means I have to use the much more expensive special-purpose insecticides which cost Sh10,000,” the coffee technologist said.
Related News: Rising temperatures lead to proliferation of coffee diseases
Related News: Embu coffee farmer 4X spraying costs in battle against berry borer
Related News: Farmers fearing coffee sales ban on new rules can check their farms online
This season however he will find his options for these effective pesticides limited to only those containing Carbosulfan. This was after the Pest Control Products Board (PCPB) banned the entry of chlorpyrifos into Kenya in July of last year. With the only effective pesticides he is left with containing one ingredient he now also runs the risk of the pest becoming resistant to Carbosulfan-based pesticides in five to ten years.
Up to 150 coffee berry borer pests can live in one berry on the ground, giving them shelter and food. Once the first rains fall, the female berry borers fly from the coffee berries on the ground and drill into the fresh green berries on the tree. They feed on the berry and lay eggs inside it before the new females’ adults fly away to attack a different berry or where they continue multiplying waiting for any signs of rain to emerge and reinfect the new coffee crop again.
To fight against the coffee berry borer, Ben Gitonga, a coffee grower in Chogoria, Tharaka Nithi County picks and prunes every coffee cherry from his half-acre farm in February and September ahead of the rains and coffee’s flowering season.
According to research done on coffee farms in Hawaii, picking and burning dead cherries before coffee’s flowering season when the coffee berry borer emerges to attack the young coffee has been shown to reduce CBB infections by up to 61 per cent.
“We were informed by an Osho extension at the Meru and Tharaka Nithi fair in 2022 that dead berries could be the source of the tiny black beetles that had infested our farms. He advised us to pick the berries and burn them as well as using insecticides,” Gitonga informed.
Related News: Rainforest Alliance introduces tool to help coffee farmers avoid being locked out of EU market
Related News: Farmers develop disease & drought-tolerant coffee varieties through grafting
Clearing the berries and using general-purpose insecticides such as Lexus ahead of every flowering season has proved effective in helping deal with CBB.
The coffee berry borer-infected cherries can only be destroyed by burning, burying them 45 centimeters deep into the soil, or boiling them in hot water otherwise the pest will crawl back to feed on your coffee.