Location: Tropical Crop and Commodity Protection Research
2019 Annual Report
Objectives
The long-term goals of our research program are to develop and protect U.S. export markets for fresh tropical commodities. An emphasis is placed on expanding and diversifying agriculture and agricultural exports in Hawaii and other states by providing environmentally sound, economically viable systems, treatments, or processes that control quarantine pests, ensure product quality, and increase product value while safeguarding the agriculture of other states. Our research will address four broad objectives over the next 5 years:
Objective 1: Develop new or improved postharvest treatments or technologies for fresh tropical commodities to ensure security against quarantine pests, including new irradiation treatments for western flower thrips, and various ants on fresh fruits.
Sub-objective 1A. Develop quarantine irradiation treatments for western flower thrips, coffee berry borer, rough sweetpotato weevil, and red imported fire ant.
Sub-objective 1B. Develop a quarantine cold treatment for melon fly in citrus.
Sub-objective 1C. Determine the effectiveness of hypobaric treatments against surface pests.
Objective 2: Develop new or improved postharvest treatments or systems (such as hypobaric storage and modified atmospheres) to improve quality and extend shelf life of tropical horticultural crops subjected to quarantine treatment.
Sub-objective 2A. Determine hypobaric storage conditions that retain quality and extend storage life of fresh tropical fruit.
Sub-objective 2B. Develop combination treatments of modified atmosphere packaging and irradiation to retain quality of exported fresh papaya.
Objective 3: Develop or improve preharvest methods for surveillance, detection, and control of invasive tropical plant pests of quarantine significance, such as coffee berry borer.
Sub-objective 3A. Study the ecology of Cathartus quadricollis and other predatory flat bark beetles and explore ways to increase their role in suppressing coffee berry borer populations in coffee.
Objective 4: Develop multiple-component systems approaches to decrease the severity of or need for commodity treatments.
Sub-objective 4A. Quantify systems approaches for quarantine security of melon fly.
Approach
The approach is to develop quarantine treatments, such as low dose irradiation and hypobaric treatments, and other mitigation techniques for fresh tropical commodities and ornamental crops. Quarantine irradiation treatment will be developed for rough sweetpotato weevil, in sweet potato, western flower thrips, red imported fire ant, and coffee berry borer. Optimum hypobaric treatment parameters for maritime shipment of tropical fruits to preserve quality and extend shelf life will be determined. We will establish the tolerance of tropical fruits to any new or modified quarantine treatments.To expand markets for high-value tropical specialty fruit, we will develop postharvest disease and packaging strategies to extend shelf life. Integrated pest management strategies for coffee berry borer will focus on understanding the population dynamics and ecology of predatory flat bark beetles and improving rear-and-release systems. A cold treatment will be developed for melon fly in citrus. Also, a systems approach will be developed for melon fly control in covered tomatoes using mass trapping, protein baits and sanitation.
Progress Report
This research project develops pre-harvest and postharvest treatments or systems to control quarantine pests, while retaining the quality and shelf-life of tropical crops. The project supports the expansion and diversification of U.S. exports of fresh tropical crops, while protecting U.S. agriculture from pest incursions.
Predator breeding station were developed to augment biological control of the coffee pest coffee berry borer (CBB). In the laboratory, breeding stations stocked with 100 Cathartus quadricollis adults and placed in sealed ventilated buckets were shown to produce 10,000 adults over four months, demonstrating the ability of the stations to augment predator populations on coffee farms. These stations are now available commercially and deployment could help suppress populations of coffee berry borer in Hawaii coffee. Another natural enemy of coffee berry borer, the parasitoid Phymasticus coffea, which attacks CBB adults, is under evaluation for efficacy and safety in quarantine. Parasitoids are being imported from a colony at Cenicafe in Colombia and tested against various native and exotic scolytine beetles in Hawaii. Thus far, P. coffea appears to be quite host specific, attacking only H. hampei and its congener the tropical nut borer Hypothenemus obscurus, an exotic pest of macadamia nut.
Modified atmosphere packaging (MAP) creates a low oxygen environment that may increase radiation tolerance in quarantine insect pests. A study with Oriental fruit fly infesting mangos in several types of commercial MAP bags showed that MAP increased mortality compared to irradiation treatment alone, suggesting quarantine treatments will not be compromised by the low oxygen environment.
A thyme and oregano oil extract embedded in methyl cellulose or chitosan films was shown to provide control of rice weevil, and Aspergillus and Penicillium molds in packaged rice.
Effective fumigation treatments and protocols may help Hawaii ornamental crop growers overcome shipment rejections to the mainland and abroad due to quarantine restrictions. Ethyl formate fumigation was effective at killing various stages of western flower thrips and melon thrips Hawaii without noticeable decrease in orchid shelf life. These thrips cause most of the rejections of cut orchid flower exports from Hawaii. Ethyl formate fumigation was also effective at controlling coconut mealybug and little fire ant which are the main problems in cut ginger flower exports.
Identification of the recruitment trail pheromone in little fire ant might help improve efficacy of toxic baits for this important urban and agricultural pest. In laboratory bioassays, chemicals in the Dufour’s gland of workers elicited trailing behavior in little fire ant workers. Hexane extracts of 1,000 Dufour’s glands were further fractionated on silica gel columns using solvents of increasing polarity (hexane, dichloromethane, then methanol). Only dichloromethane and methanol fractions elicited trailing behavior, suggesting existence of potential trail pheromone components in those two fractions.
Erythritol (a non-nutritive sugar) ingestion increased mortality of Mediterranean fruit fly, oriental fruit fly, melon fly and solanaceous fruit fly Hawaii in a dose-dependent manner. Adult oriental fruit flies fed with 0.5M sucrose + 2.0M erythritol solution invariably died within 6-10 days. Before they die, flies fed with erythritol laid significantly fewer eggs.
In coffee quality research, the sensitivity of a portable electronic nose (enose) was compared to head space gas chromatography/mass spectroscopy (HS/GC/MS) for assessing coffee defects based of volatile analysis. Both HS/GC/MS and enose were able to differentiate undamaged coffee from damaged coffee (pinholes and chipped). However, the enose was not able to discriminate between undamaged and moldy coffee beans in preliminary tests, but enose model parameters are still being optimized.
Postharvest irradiation treatments may help New Zealand (NZ) and other fruit exporting countries overcome quarantine restrictions during fruit fly outbreaks. Studies in Hawaii showed that apples and kiwifruit were moderately good potential hosts for Mediterranean fruit fly and oriental fruit fly but poor potential hosts for melon fly. In fruit quality research, the differential tolerance of five NZ apple cultivars to potential x-ray disinfestation for codling moth showed that ‘Royal Gala’ was the most susceptible cultivar, with flesh browning increased after longer pretreatment storage times and as dose increased above 400 Gy. Other cultivars including ‘Jazz’, ‘Envy’ and ‘Fuji’ did not show damage after x-ray irradiation regardless of storage time and dose.
Accomplishments
1. Predator breeding stations for augmentative biological control of coffee berry borer. Coffee berry borer (CBB) is a serious pest of coffee worldwide and a relatively new invasive pest in Hawaii. The flat bark beetle, Cathartus (C.) quadricollis, is a significant predator of CBB in Hawaii that may help suppress populations in unharvested coffee left on the tree between seasons and on abandoned farms. C. quadricollius is also a stored product pest known as the square-necked grain beetle. Several informational workshops on the predators were hosted by researchers in Hilo, Hawaii, and the University of Hawaii County Extension, and predator ‘starter kits’ (buckets with food and predator beetles) were distributed to over 300 coffee growers. A commercial breeding station was developed with a commercial supplier using a pheromone to attract Cathartus quadricollis to a food source (cracked corn) where they feed, multiply and disperse on the coffee farm. The commercial availability of breeding stations should facilitate grower adoption of predator augmentation technology and improve coffee berry borer control in Hawaii coffee.
2. Novel repellent for the fruit pest spotted wing drosophila. Spotted wing drosophila (SWD) is from south-eastern Asia and has become a major pest of berries and cherries worldwide. Unlike other closely related Drosophila species that infest mainly damaged and overripening fruits, SWD is a pest of great concern, as it can infest maturing and ripening fruit using its serrated ovipositor. Due to its rapid life cycle, most growers use weekly calendar-based pesticide applications that can lead to development of resistance, so alternative approaches to its management are desperately needed, such as manipulating SWD behavior through semio-chemicals. Researchers in Hilo, Hawaii, identified a novel SWD repellent made from microbes and fruit that significantly reduced SWD infestation of ripe raspberries, a preferred fruit host. This repellent is a food-grade flavor chemical, is safe, and is more effective than the previously identified SWD repellent 1-octen-3-ol. A commercial supplier of this repellent has been identified and the commercial availability of an effective repellent should facilitate grower adoption of more sustainable management practices for SWD.
Review Publications
Walker, H.E., Lehman, K.A., Wall, M.M., Siderhurst, M.S. 2018. Analysis of volatile profiles of green Hawaiian coffee beans damaged by the coffee berry borer (Hypothenemus hampei). Journal of the Science of Food and Agriculture. 99(4):1954-1960. https://doi.org/10.1002/jsfa.9393.
Follett, P.A., Jamieson, L., Hamilton, L.J., Wall, M.M. 2018. New associations and host status: infestability of kiwifruit by Bactrocera dorsalis, Bactrocera cucurbitae, and Ceratitis capitata (Diptera: Tephritidae). Crop Protection Journal. 115:113-121. https://doi.org/10.1016/j.cropro.2018.09.007.
Follett, P.A., Pinero, J., Jamieson, L., Souder, S., Waddell, B., Wall, M.M. 2019. Host status of ‘Scifresh' apples to the invasive fruit flies Bactrocera dorsalis, Zeugodacus cucurbitae, and Ceratitis capitata (Diptera: Tephritidae). Journal of Asia Pacific Entomology. 22(2):458-470. https://doi.org/10.1016/j.aspen.2019.01.019.
Hardner, C.M., Wall, M.M., Cho, A. 2019. Global macadamia science: Overview of the special section from the 2017 International Macadamia Research Symposium. HortScience. 54(4):592-595. https://doi.org/10.21273/HORTSCI13543-18.
Hossain, F., Follett, P.A., Dang Vu, K., Salmieri, S., Fraschini, C., Jamshidian, M., Lacroix, M. 2019. Antifungal activity of combined treatments of active methylcellulosic based films containing encapsulated nanoemulsion of essential oils and µ-irradiation: in vitro and in situ evaluations. Cellulose. 26(2):1335-1354. https://doi.org/10.1007/s10570-018-2135-2.
Hossaine, F., Follett, P.A., Lacroix, M. 2019. Synergistic effects of nanocomposite films containing essential oil nanoemulsions in combination with ionizing radiation for control of rice weevil Sitophilus Oryzae in stored grains. Journal of Food Science. 84(6):1439-1446.
Avanesyan, A., Snook, K., Follett, P.A., Lamp, W. 2019. Short-term physiological response of a native Hawaiian plant, Hibiscus arnottianus, to injury by the exotic leafhopper, Sophonia orientalis (Hemiptera: Cicadellidae). Environmental Entomology. 48(2):363-369. https://doi.org/10.1093/ee/nvy193.
Follett, P.A., Hollingsworth, R., Wall, M.M., Calvert, F. 2019. Survey of flowering plants in Hawaii as potential banker plants of Anthocorid predators for thrips control. Journal of Asia-Pacific Entomology. 22(3):638-644. https://doi.org/10.1016/j.aspen.2019.05.001.
Wolfin, M.S., Volo, S.L., Chilson, R.R., Liu, Y., Cha, D.H., Cox, K.D., Loeb, G.M., Linn, C.E. 2019. Plants, microorganisms and odorants involved in insect host plant location: who’s making the message? Entomologia Experimentalis et Applicata. 167(4):313-322. https://doi.org/10.1111/eea.12778.
Cha, D.H., Loeb, G.M., Landolt, P.J., Linn, C.E., Hesler, S.P. 2018. A multiple-choice bioassay approach for rapid screening of key attractants from complex mixtures of fermentation volatiles. Environmental Entomology. 47(4):946-950. https://doi.org/10.1093/ee/nvy054.
Wallinford, A.K., Cha, D.H., Linn, C.E., Wolfin, M.S., Loeb, G.M. 2018. Robust manipulations of pest insect behavior using repellents and practical application for integrated pest management. Environmental Entomology. 46(5):1041-1050. https://doi.org/10.1093/ee/nvx125.
Follett, P.A., Manoukis, N., Mackey, B.E. 2018. Comparative cold tolerance in Ceratitis capitata and Zeugodacus (Bactrocera) cucurbitae (Diptera: Tephritidae). Journal of Economic Entomology. 111(6):2632-2636. https://doi.org/10.1093/jee/toy227.
Follett, P.A. 2018. Irradiation for quarantine control of coffee berry borer, Hypothenumus hampei (Coleoptera: Curculionidae: Scolytinae) in coffee and a proposed generic dose for snout beetles (Coleoptera: Curculionoidea). Journal of Economic Entomology. 111(4):1633-1637. https://doi.org/10.1093/jee/toy123.
