|JOHNSON, MELISSA - Orise Fellow|
|FORTNA, SAMUEL - University Of Hawaii|
Submitted to: Crop Protection Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/8/2020
Publication Date: 6/11/2020
Citation: Johnson, M.A., Fortna, S., Manoukis, N. 2020. Evaluation of exclusion netting for Coffee Berry Borer (Hypothenemus hampei) management. Crop Protection Journal. 11:364. https://doi:10.3390/insects11060364.
Interpretive Summary: In this study we examined the potential of exclusion netting to protect coffee beans from Coffee Berry Borer (CBB). Such a method could be a viable alternative to insecticides and help minimize high labor costs in the small coffee farms of Hawaii which produce a high-value coffee. Comparison of enclosed vs. open (control) trees showed much lower infestation, higher yield, comparable quality, and marginal differences in climate in screened vs. open trees, even though sunlight was much reduced to the screened trees. We conclude that exclusion netting is a promising control method against CBB in small farms.
Technical Abstract: Exclusion nets are increasingly being used to protect a variety of agricultural crops from insect pests as a sustainable alternative to chemical controls. In this study we investigated the effectiveness and feasibility of a complete exclusion system for controlling the world’s most damaging insect pest of coffee, Hypothenemus hampei (“coffee berry borer”), on two commercial coffee farms located in the Ka’u district of Hawaii Island. We recorded microclimate (temperature, solar radiation, and relative humidity), fruit infestation, population per fruit, sex ratio, mortality by Beauveria bassiana, coffee yield, and coffee quality in four paired exclusion and control (un-netted) plots on both farms. Fruit harvested from exclusion plots had significantly lower infestation compared to un-netted control plots (4% vs. 11%). We observed no difference in the number of CBB per fruit (13 vs. 14) or the female:male sex ratio per fruit (9:1 vs. 11:1) in exclusion plots relative to control plots. CBB mortality was higher in exclusion plots, though not significantly so (18% vs. 16%). Mean and maximum daily temperature and relative humidity were similar between exclusion and control plots, while mean and maximum daily solar radiation was reduced by ~50% in exclusion plots. Ripe fruits harvested from exclusion plots were on average significantly heavier and wider than those from control plots, and the average yield per tree was found to be higher in exclusion plots (var. typica, 4.51 vs. 3.71 kg/tree) or similar between the two treatments (var. catuai, 4.79 vs. 5.00 kg/tree). Lastly, coffee quality was not affected by exclusion netting, with coffee from both treatments having an average cupping score of 82 (specialty grade coffee). Results from this study suggest that exclusion netting can be used to successfully control CBB on small-scale coffee farms and can serve to reduce both production and labor costs by eliminating the need to spray chemical pesticides.