Coffee berry borer infestations and natural enemy communities shaped by altitude, shade, and management practices

The coffee berry borer (Hypothenemus hampei Ferrari, CBB) is the most damaging pest of coffee worldwide, and challenging to control due to its cryptic life cycle inside the coffee berries. Conservation biological control offers a sustainable alternative by enhancing natural enemies through habitat management. However, its potential to control CBB remains unclear. Here we studied the impact of chemical control, shade trees, crop characteristics, farm management, and arthropod natural-enemy populations on CBB infestations across 24 coffee farms in Colombia in two consecutive years. We visually assessed infestation levels, berry damage, and predator and parasitoid abundance and diversity using sweep netting (flying insects), beat-sheet sampling (tree-dwelling species), and tuna baits (predatory ants). Farm characteristics and management practices were documented through interviews with farmers. CBB infestations averaged 4.5 % (2022) and 14.6 % (2023), and we identified ten ant and two beetle species as potential CBB predators inside infested berries. Chemical control of CBB was ineffective, and infestation levels were not associated with the presence of shade trees, but were negatively correlated with altitude. Natural enemy diversity was positively associated with shade-coffee systems and tree density, and negatively associated with weed mowing frequency. Our findings highlight the complex interactions between environmental factors, management practices, and coffee crop characteristics in shaping CBB infestations and natural enemy communities. Weeding negatively impacted natural enemies, whereas shade and higher crop density enhanced predator and parasitoid diversity, reinforcing the value of structural vegetation complexity. Enhancing natural enemy populations through vegetation diversification, reduced weed mowing, and maintaining shade trees may offer scope for CBB suppression.