Block-stumping as an effective and cost-efficient style of pruning to reduce coffee berry borer (Hypothenemus hampei Ferrari) infestation and damage in Hawaiian coffee farms

Pruning is a cultural practice conducted by coffee farmers to increase production and facilitate the management of insect pests and diseases. This field study assessed the impact of different pruning styles on the regulation of coffee berry borer (CBB, Hypothenemus hampei ), widely considered the most damaging insect pest of coffee worldwide. For each pruning system (block-stumping, Kona style, topping, and Beaumont-Fukunaga), 3-4 coffee lots were selected on Hawaiʻi Island and CBB infestation, bean damage, and harvesting efficacy was evaluated in 2023 and 2024. Yields, sale price, and pruning costs were also recorded to calculate the benefit cost ratio of each pruning style. Block-stumping resulted in significantly lower CBB infestation (0.6% and 2.6%, year one and two of harvest) relative to Beaumont-Fukunaga (6.3%), topping (8.6%) and Kona style (10.0%). Block-stumping also resulted in significantly lower bean damage (2.6%) compared to topping (24.3%) and Kona style (25.6%). The most effective harvesting was done in lots that were block-stumped (≤6.7 berries left per tree), while Beaumont-Fukunaga (10.9), topping (14.5), and Kona style (15.7) resulted in low harvesting efficacy. While there was no significant difference among pruning styles, the benefit cost ratio was higher in lots that employed block-stumping (2.29) or Beaumont-Fukunaga (2.29) compared to topping (2.18) and the traditional Kona style (2.04). Our findings suggest that block-stumping is the optimal pruning style for reducing CBB infestation and bean damage, and results in improved harvesting efficacy and a higher benefit cost ratio relative to other pruning styles that are commonly used in Hawaiʻi. • Block-stumping was the most effective pruning strategy in reducing CBB damage • Kona style had the highest infestation and bean damage and lowest harvest efficacy • Yields were highest in block-stumped lots and lowest in Kona style lots • Profit losses were highest in Kona style lots and lowest in block-stumped lots • Block-stumping is the optimal pruning strategy for managing CBB in coffee farms