CTAHR faculty and staff, with the support of HDOA, USDA, and grower-cooperator Greenwell Farms, have conducted research trials on coffee-pruning techniques and pesticide residues in green coffee beans at the Kona and Mealani Research Stations. Information and outreach from both trials will increase farmers’ ability to manage coffee berry borer (CBB) and produce high-quality specialty coffee.
Preliminary results from the first year of harvest in the three-year pruning trial show that single or double vertical, hand-hedged trees provide nearly 1.5 times greater yield in the first season of harvest compared with Kona-style pruned coffee trees, and 3 times greater yield compared with stumped trees. However, pruning, de-suckering, and harvesting the hand-hedged trees also requires about twice as much labor.
CBB can be managed while using all these methods of pruning, provided that there is proper field sanitation in and around the farm and that Beauveria bassiana sprays are well timed and provide good coverage.
Results of the coffee pesticide residue trial determined that a synergist, piperonyl butoxide or PBO, was present in green (dried, unroasted) beans when coffee berries were sprayed up to 105 days pre-harvest. The PBO residues were greater than those allowed by export countries such as Japan. The researchers are recommending that growers avoid using products containing PBO on coffee so as to eliminate the risk of rejection for exported coffee to such countries. Other pesticides tested did not result in detectable residues in green coffee.