Risk assessment of ozone fumigation under vacuum to control potential infestation of coffee berry borer and coffee leaf rust in green coffee beans imported into Hawaii

Authors: Portilla, Maribel; Follett, Peter; Armstrong, John; Leesch, James; Tebbets, John; Smilanick, Joseph; McHugh, Tara; Olsen, Carl; Whitehand, Linda; CAVALETTO, C. - University Of Hawaii; BITTENBENDER, H. - University Of Hawaii; BUSTILLO, ALEX - Cenicafe; PENA, JORGE - Florida State University

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/4/2021
Publication Date: 8/27/2021
Citation: Portilla, M., Follett, P.A., Armstrong, J.W., Leesch, J.G., Tebbets, J.S., Smilanick, J.L., Mchugh, T.H., Olsen, C.W., Whitehand, L.C., Cavaletto, C., Bittenbender, H., Bustillo, A., Pena, J.E. 2021. Risk assessment of ozone fumigation under vacuum to control potential infestation of coffee berry borer and coffee leaf rust in green coffee beans imported into Hawaii. Journal of Economic Entomology. 114(6):2277-2289. https://doi.org/10.1093/jee/toab165.
DOI: https://doi.org/10.1093/jee/toab165

Interpretive Summary: It is well known that the high standards for Hawaiian coffee (extra fancy, fancy, and number one) are not comparable to the global average with values ranging from US $30 to $120. Therefore, maintaining this high quality is crucial for the Hawaian coffee industry and its coffee producers. Coffee companies in Hawaii import green coffee beans from the US mainland for blending and roasting with locally grown coffee, and this imported green coffee (25.5 million lb) is the foundation for the roasting, blending, and brewing sectors of the Hawaii coffee industry. Green coffee is not shipped directly to Hawaii from the coffee growing and exporting areas of the world, but instead is shipped to ports on the US mainland, where it is fumigated with methyl bromide (MB) or treated with moist heat to kill potential infestations of coffee berry borer and coffee leaf rust. However, neither of those treatments as currently proposed (USDA-APHIS, 2006) are efficacious against these two major pests of concern that currently are devastating coffee farms across Hawaii. Therefore, our goal was to develop ozone vacuum fumigation as a methyl bromide alternative. The present study was the first report of a postharvest ozone treatment for coffee berry borer and coffee leaf rust and its possible effect on the coffee quality.

Technical Abstract: Studies were conducted with ozone gas fumigation under vacuum as a methyl bromide alternative against life stages of coffee berry borer (CBB) Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae: Scolytinae), and the urediniospores of coffee leaf rust (CLR), Hemileia vastatrix Berkeley & Broome (Basidiomycota: Pucciniales) in green coffee, Coffea spp. L. Fumigation with 10,000 ppm O3 gas under -25.4 mm Hg vacuum at 13.0 ± 3.0°C for 6.0 h killed all CBB larvae, pupae, and adults, but did not kill all CBB eggs (~15% survival). Mortality of CLR urediniospores was 100% within the first hour of the 6-h fumigation. Ozone fumigation had no adverse effects on coffee quality. Results indicated that CBB adult hitchhikers may be the only target life stage of quarantine concern, and additional studies focused on this stage. CBB adult survival and reproduction decreased significantly at moisture contents = 20%, and F1 generation survival did not occur in green coffee at moisture contents = 15%. As the international standard for green coffee moisture content is 9-12%, adult CBB should not survive or reproduce in exported dry green coffee. Standard industry processing of harvested coffee cherries to the green coffee stage using either mechanical- or sun-drying eliminated CBB infestations from the field. A systems approach is recommended for exporting green coffee to control CBB and coffee leaf rust that includes eliminating CBB life stages with standard processing methods, reducing moisture content to 9-12% to prevent egg deposition, survival or reproduction, and O3 fumigation to ensure quarantine security against potential CBB adult hitchhikers.