Research Project: Postharvest Protection of Tropical Commodities for Improved Market Access and Quarantine Security

Location: Tropical Crop and Commodity Protection Research

2023 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 three broad objectives over the next 5 years: Objective 1: Develop new or improved postharvest treatments or technologies for fresh tropical commodities that mitigate risks associated with quarantine pests and improve quality and shelf-life. • Sub-objective 1A. Develop quarantine irradiation treatments for western flower thrips, tropical nut borer, and the semi-slug Parmarion martensi. • Sub-objective 1B. Evaluate ethyl formate fumigation for thrips control in ornamentals. • Sub-objective 1C. Determine the quality and shelf life of fresh commodities subjected to quarantine irradiation treatment. Objective 2: Develop new preharvest methods for the monitoring and control of phytosanitary and quarantine pests and commodity quality improvement. • Sub-objective 2A. Develop oviposition deterrents for behavioral control of oriental fruit fly and spotted wing drosophila. • Sub-objective 2B. Identify trail pheromone components of little fire ant for improved management in Hawaii. • Sub-objective 2C. Determine preharvest factors that increase aflatoxin prevalence in macadamia nuts. Objective 3: Develop risk management systems and systems approaches to control tropical plant pests and decrease the intensity or need for commodity treatments. • Sub-objective 3A. Evaluate predator breeding stations for augmentative biological control of coffee berry borer in coffee. • Sub-objective 3B. Conduct classical biological control of coffee berry borer using the adult parasitoid Phymasticus coffea. • Sub-objective 3C. Develop a multi-component system for determining chemical and sensory quality associated with coffee berry borer (CBB) damaged coffee and other coffee defects.

Approach
Obj 1A: Quarantine irradiation treatments for western flower thrips, tropical nut borer, and the slug Parnarion martensi will be developed. Dose response data will be generated for mortality, fecundity and fertility. Irradiation treatments will be submitted to USDA APHIS and the IPPC for approval. 1B: Ethyl formate fumigation for postharvest thrips control in ornamentals will be developed, including orchids. Efficacy trials will be conducted with nymph and adult stages using fumigation across concentrations and times. Preliminary data show thrips can be controlled at very low ethyl formate concentrations without loss of orchid quality. 1C: The quality & shelf life of fresh commodities subjected to quarantine irradiation treatment will be determined, particularly for breadfruit. Fresh breadfruit will be irradiated and evaluated for physical, chemical & sensory attributes. If quality is negatively impacted at phytosanitary doses, then combination treatments with hot water or 1-MCP will be tested. Obj 2A: Oviposition deterrents for behavioral control of oriental fruit fly and spotted wing drosophila will be developed. Chemical odors will be extracted from fruits and fungi and screened for attraction or antagonism to fruit flies using field cage tests or GC-EAD & GC-MS analysis. Oviposition deterrents might reduce insecticide spraying. 2B: Trail pheromone components of little fire ant will be identified. Potential candidates will be extracted from venom sac/Dufour’s glands of LFA workers and trails created on epiphytic moss. Bioactivity will be determined via behavioral, chemical and electrophysiological techniques. Pheromones with toxic baits could improve discovery, worker recruitment, and delivery to nests workers. 2C: Preharvest factors increasing aflatoxin in macadamia nuts will be determined. Samples from fields and processor will be evaluated for insect damage & aflatoxins. A prototype in-line fluorescence detector for contaminated nuts will be developed. Aflatoxin detection in immature or insect-damaged nuts can allow mitigation via preharvest insect control, timely harvests, & postharvest sorting. Obj 3A: Predator breeding stations will be evaluated for augmentative biological control of coffee berry borer (CBB) in coffee. Sleeve cages and artificial berries will be used to quantify predation rates in flat bark beetle predators of CBB. Breeding stations will be evaluated for their ability to multiply & augment predators. Increased predators in coffee farms should result in lower CBB populations. 3B: Classical biological control of CBB using the parasitoid Phymasticus coffea will be conducted. P. coffea will be imported from Colombia & tested in quarantine against native and exotic scolytine prey to determine host range. If P. coffea shows no significant nontarget effects, release permits will be obtained. 3C: A system to determine chemical & sensory quality of CBB-damaged coffee will be developed. Methods for volatiles analysis will be developed to distinguish damaged from undamaged beans. If volatile and sensory analyses are effective in differentiating CBB damaged coffee the methodology will be applied to detect other coffee defects.

Progress Report
This report documents fiscal year (FY) 2023 progress for project 2040-43000-018-000D, titled, “Postharvest Protection of Tropical Commodities for Improved Market Access and Quarantine Security”. In support of Sub-objective 1B, ARS researchers in Hilo, Hawai'i continued in the development and application of effective ethyl formate fumigation to reduce shipment rejections of ornamental crop exports from Hawaii to the continental United States due to insects. Thrips cause most of the rejections in exported cut orchid flowers. Dose response tests revealed that one hour ethyl formate fumigation of 7.42 gigahertz (gh)/m3 at 23 degrees C was effective at controlling western flower thrips and melon thrips. Ethyl formate fumigation had no noticeable effect on flower color and shelf life. In support of Sub-objective 1C, three breadfruit varieties (Ma’afala, Fiti, and Otea) were subjected to X-ray radiation as a quarantine treatment. Fruit ripening and softening were delayed when treated with doses ranging from 200 to 800 Gy and stored at 13 degrees C, indicating that irradiation maintains postharvest quality in comparison to untreated fruit. In research to extend breadfruit shelf-life, treatment with the ethylene inhibitor, 1-MCP, delayed the respiratory peak and increased the time to full softening for Ma’afala breadfruit, but did not inhibit discoloration. In support of Sub-objective 2A, 2-pentylfuran (a patent pending compound isolated from a fermentation product) was identified by ARS researchers, as a novel repellent compound of spotted wing drosophila. Current control methods to reduce fruit infestation by spotted wing drosophila are based on the repeated application of pesticides, which may not be sustainable due to resistance, cost, and negative impact on the environment and beneficial insects. When released from polyethylene sachets around raspberries (a preferred host of spotted wing drosophila) 2-pentylfuran could reduce oviposition on fruit by 50% in the field. The CRADA partner (Scentry Biologicals Inc) has developed prototype spiral dispensers of 2-pentylfuran, which will be tested in the field during the 2023 growing season. Oviposition deterrents of spotted wing drosophila and oriental fruit fly were identified from coconut oil-derived natural product chemicals. A provisional patent application for the oviposition deterrent has been filed. In support of Sub-objective 2B, research to identify the chemical components of the little fire (LFA) ant trail pheromone continued. LFA is a nuisance pest in many agricultural crops in Hawaii that can inflict a painful sting. Adding trail pheromone to little fire ant baits may help recruitment of workers to toxic baits and improve the efficacy of the baits. Chemicals in the Dufour’s gland of the workers of little fire ants were extracted and behaviorally tested for elicitation of trailing behavior. In laboratory bioassays, chemicals in the Dufour’s gland elicited trailing behavior from the workers of little fire ant. Different solvent fractions of the gland extracts will be subject to bioassays to confirm and identify bioactive fraction(s) that induce trailing behavior. Using arena assays, we showed behavioral evidence of the presence of LFA queen pheromone that can suppress rearing of LFA queens among broods. In support of Sub-objective 2C, field sampling of macadamia nuts and laboratory analyses for aflatoxins (AF) indicated that insect damage was positively correlated with higher levels of AF in commercial orchards. A subsequent field study was designed to determine whether tropical nut borer (TNB) damage, specifically, was correlated with aflatoxin incidence in macadamia orchards. However, no clear relationship was determined, possibly due to unsuitable (dry) environmental conditions for Aspergillus species to develop and produce AF. In support of Sub-objective 3A, a predator breeding station consisting of a screened and sheltered enclosure containing food (250 g of cracked corn: cornmeal [4:1, w:w] mix) and the membrane-type quadrilure lure was developed by ARS researchers to augment predator numbers in coffee and macadamia fields. In the laboratory, stocking a breeding station with 100 C. quadricollis resulted in production and dispersal of about 10,000 adults per station over a four-month period at 25 degrees C. The predator breeding station was an efficient way to multiply C. quadricollis numbers in the field that can be used to augment biological control of the coffee berry borer in coffee and tropical nut borer in macadamia nut. To advance Sub-objective 3B, a draft environmental assessment (DEA) and a cultural impact assessment were submitted to regulatory authorities to seek approval for the release of Phymasticus coffea, a parasitoid of the adult coffee berry borer (CBB). P. coffea, originally from Africa, has been introduced against CBB in many coffee-producing countries. The Hawaii Department of Agriculture and USDA APHIS reviewed the DEA and host specificity information and determined the parasitoid could be released safely with no threat to the Hawaii environment. This classical biocontrol will give coffee growers an additional tool to help control CBB. In support of Sub-objective 3C, the potential impact of CBB infestations on coffee volatiles and cupping quality was investigated using the portable electronic nose (e-nose). The e-nose was not able to differentiate differences in volatile abundance for CBB infested beans but was useful for detecting moldy green coffee beans. A sensory panel has been trained to evaluate specialty coffee flavor and aroma, and to identify and differentiate off-flavors and aromas of multiple coffee defects in roasted samples, including CBB damage. In other research, chitosan coatings containing carvacrol were developed for postharvest preservation of guava fruit. Chitosan coatings containing 0.2% carvacrol were better at maintaining postharvest quality compared to the coatings with chitosan alone, resulting in higher firmness, soluble solid content, and total acid, and lower weight loss, pericarp browning, and decay rate. Tahitian limes are perishable and may be infested with fruit flies and thus require a quarantine treatment such as irradiation. The effects of wax coatings and X-ray irradiation on the physical and biochemical changes in limes were evaluated during postharvest storage. The coating significantly reduced weight loss which may extend the fruit’s shelf life, and X-ray doses up to 400 Gy, which are suitable for insect control, did not adversely affect fruit quality. Only ‘Sharwil’ variety avocados are approved for export from Hawaii to the continental United States, but other varieties sometimes get mixed in. A technique was developed to authenticate Hawaii Sharwil avocados for export using a handheld near-infrared (NIR) spectrometer. The prediction model showed over 95% accuracy in identifying ‘Sharwil’ from other similar varieties. Macadamia has several key pests that reduce nut yield and quality, and tree health. Field experiments with tropical nut borer (TNB) showed that methanol-containing lures are more attractive than ethanol-based lures, and transparent traps capture more beetles than traps painted with a solid color. On the management side, long-lasting insecticidal netting, and sprays of the biopesticide Beauveria bassiana both show potential for control of TNB. Molecular analysis of moth larvae has shown that the pest Cryptophebia ombrodelpta is significantly more common infesting macadamia nuts then the related species C. illepida. Spatial and temporal patterns of moth activity tend to vary between species and location, and egg laying activity and injury are generally higher at the exterior of the orchards than in the interior.

Accomplishments
1. Export procedures for Malama avocados from Hawai’i. Avocados grown in Hawai’i cannot be exported to the continental United States without a quarantine treatment or other mitigation measures to control possible infestation by Oriental fruit fly. Quarantine cold, heat, and irradiation treatments are harmful to fruit quality and other approaches were needed. ARS researchers in Hilo, Hawai’i showed that Malama is a poor host for fruit flies and fruit are rarely infested. A systems approach was developed based on poor host status, low prevalence, and a limited harvest period (October to March) and distribution area (northern tier states) to safely export Malama avocados from Hawai’i to the continental United States.

2. Novel method for repelling pest Drosophila species. A U.S. patent (US11432548B2) on “Methods for repelling Drosophila species using 2-pentylfuran” was granted to ARS researchers in Hilo, Hawai’i, on September 6, 2022, which will help berry and cherry growers reduce spotted wing drosophila damage to fruit without the repeated use of insecticides.

3. Controlled-release 1-methylcyclopropene (1-MCP) films to postharvest preservation of papaya fruit. Papaya is a climacteric fruit that ripens and senesces rapidly after harvest accompanied by susceptibility to pathogens. ARS researchers in Hilo, Hawai’i found that 1-Methylcyclopropene (1-MCP), which is a synthetic plant growth regulator, can slow ethylene release and delay softening. Results showed that use of a controlled-release 1-MCP bioactive film at 1-2 parts per million (ppm) could extend the shelf life of 'Rainbow' papaya during commercial shipments.

4. Turmeric-fortified pineapple juice beverage. Turmeric has been increasingly used by the beverage industry to produce functional drinks due to its high nutritional, antioxidant and antiinflammation properties. Turmeric drinks have a strong earthy and spicy taste profile and mixing it with a sweet fruit juice may improve its flavor and acceptability. Beverage mixtures based on pineapple and turmeric juice as a ready-to-drink product were developed by ARS researchers in Hilo, Hawai'i, and their physicochemical, nutritional, and sensory properties were evaluated. Turmeric fortified pineapple juice with 90:10 (v:v) pineapple to turmeric could be developed into a commercial functional beverage with increased overall flavor and nutritional quality.

5. Breadfruit postharvest quality. Breadfruit is a staple food crop of Pacific Island communities, but marketing fresh fruit is limited by its rapid ripening and deterioration after harvest. In cooperative research, ARS scientists in Hilo, Hawai’i, and University of Hawai’i researchers determined maturity indices and techniques to prolong breadfruit quality after harvest. Picking breadfruit during early harvest maturity delayed discoloration, and postharvest application of an ethylene inhibitor (1-MCP) delayed breadfruit softening. Both practices have the potential to improve quality maintenance of breadfruit during transportation and storage.

Review Publications
Slusher, E., Acebes-Doria, A.L., Cottrell, T.E., Schmidt, J. 2022. Aphids and associated parasitoids exhibit vertical canopy distribution differences in pecans. BioControl. 67:563–570. https://doi.org/10.1007/s10526-022-10169-z.
Sun, X.N., Wall, M.M., Follett, P.A., Liang, P., Xu, S., Zhong, T. 2022. Effect of pectin coatings containing trans-cinnamaldehyde on the postharvest quality of rambutan. HortScience. 58(1):11-15. https://doi.org/10.21273/HORTSCI16923-22.
Dong, L., Wall, M.M., Li, Y. 2022. Behaviors of Salmonella enterica serovar Typhimurium and Listeria monocytogenes on whole avocado during storage at 21 or 7°C and their reduction by aqueous chlorine dioxide and peroxyacetic acid. LWT - Food Science and Technology. 173. Article 114359. https://doi.org/10.1016/j.lwt.2022.114359.
Follett, P.A., Asmus, G.M., Hamilton, L.J., Stockton, D.G. 2022. Susceptibility of ‘Malama’ avocados to Bactrocera dorsalis (Diptera: Tephritidae) in Hawai'i and a proposed systems approach for market access. Journal of Economic Entomology. 115(6):1894-1900. https://doi.org/10.1093/jee/toac150.
Acebes-Doria, A.L., Gayle, S.M., Cha, D.H., De Rocquigny, N., Short, B.D. 2023. Commercial lure comparison for monitoring of Cryptophlebia spp. (Lepidoptera: Tortricidae) associated with macadamia in Hawaii. Hawaiian Entomological Society Proceedings. 55:1-9.
Srimartpirom, M., Rakkrai, C., Phankum, S., Intarakamhang, R., Sonsiri, C., Buchatian, P., Phanglerk, P., Jinnalite, P., Khongthawie, S., Unahawutti, U., Follett, P.A. 2023. Vapor heat treatment for quarantine control of the oriental fruit fly (Diptera: Tephritidae) in papaya fruit from Thailand. Journal of Asia-Pacific Entomology. 26(2). Article 102049. https://doi.org/10.1016/j.aspen.2023.102049.
Pereira, G.M., Jun, S., Li, Q.X., Wall, M.M., Ho, K. 2023. Formation and physical characterization of soy protein-isoflavone dispersions and emulsions. LWT - Food Science and Technology. 176. Article 114513. https://doi.org/10.1016/j.lwt.2023.114513.
Cha, D.H., Skabeikis, D.D., Kim, B., Lee, J.C., Choi, M.Y. 2023. Insecticidal properties of erythritol on four tropical tephritid fruit flies, Zeugodacus cucurbitae, Ceratitis capitata, Bactrocera dorsalis, and B. latifrons (Diptera: Tephritidae). Insects. 14(5). Article 472. https://doi.org/10.3390/insects14050472.
Pulakkatu-thodi, I., Dzurisin, J., Follett, P.A. 2022. Evaluation of macadamia felted coccid (Hemiptera: Eriococcidae) damage and cultivar susceptibility using imagery from a small unmanned aerial vehicle (sUAV), combined with ground truthing. Pest Management Science. 78(11):4533-4543. https://doi.org/10.1002/ps.7073.
Zhang, Y., Qiu, J., Yang, K., Lu, Y., Xu, Z., Yang, H., Xu, Y., Wang, L., Lin, Y., Tong, X., He, J., Xiao, Y., Sun, X.N., Huang, R., Yu, X., Zhong, T. 2023. Generation, mechanisms, kinetics, and effects of gaseous chlorine dioxide in food preservation. Comprehensive Reviews in Food Science and Food Safety. 22(4):3105-3129. https://doi.org/10.1111/1541-4337.13177.
Sun, X.N., Follett, P.A., Wall, M.M., Duff, K.S., Wu, X., Shu, C., Plotto, A., Liang, P., Stockton, D.G. 2023. Physical, chemical, and sensory properties of a turmeric-fortified pineapple juice beverage. Foods. 12(12). Article 2323. https://doi.org/10.3390/foods12122323.
Begum, T., Follett, P.A., Shankar, S., Moskovchenko, L., Salmieri, S., Lacroix, M. 2023. Evaluation of bioactive low-density polyethylene (LDPE) nanocomposite films in combined treatment with irradiation on strawberry shelf-life extension. Journal of Food Science. 88(5):2141-2161. https://doi.org/10.1111/1750-3841.16551.
Liang, P., Ladizinsky, N.C., Asmus, G.M., Hamilton, L.J., Acebes-Doria, A.L., Manoukis, N., Follett, P.A. 2023. Artificial fruits and nuts for studying predation of cryptic prey: A case of 3D-printed coffee berries for studying predation of coffee berry borer by flat bark beetles. Entomologia Experimentalis et Applicata. 171(9):716-720. https://doi.org/10.1111/eea.13328.
Valles, S.M., Zhao, C., Rivers, A.R., Iwata, R.L., Oi, D.H., Cha, D.H., Collignon, R., Cox, N.A., Morton, G.J., Calcaterra, L.A. 2023. RNA virus discoveries in the electric ant, Wasmannia auropunctata. Virus Genes. 59:276–289. https://doi.org/10.1007/s11262-023-01969-1.
Kwon, T., Kim, D., Lee, B., Cha, D.H., Park, M. 2023. Comparison of methyl bromide and ethyl formate for fumigation of snail and fly pests of imported orchids. Insects. 14(1). Article 66. https://doi.org/10.3390/insects14010066.
Aristizabal, L.F., Johnson, M.A., Shriner, S., Wall, M.M. 2023. Frequent and efficient harvesting as an economically viable strategy to regulate coffee berry borer on commercial farms in Hawaii. Journal of Economic Entomology. 116(2):513-519. https://doi.org/10.1093/jee/toad041.
Wiseman, B.J., Paull, R.E., Lincoln, N.K., Wall, M.M. 2023. 1-methylcyclopropene and harvest maturity impact ‘Ma’afala’ breadfruit postharvest storage. HortScience. 58(6):666-670. https://doi.org/10.21273/HORTSCI17076-23.
Lee, D., Johnson, M.A., Aristizabal, L.F., Shriner, S., Chan, C., Miyasaka, S., Wall, M.M. 2023. Economic benefits from managing coffee berry borer (Hypothenemus hampei) in Hawaii. Insects. 14(4). Article 350. https://doi.org/10.3390/insects14040350.
Lee, I., So, H., Kim, J., Auh, J., Wall, M.M., Li, Y., Ho, K., Jun, S. 2023. Selective detection of Escherichia coli K12 and Staphylococcus aureus in mixed bacterial communities using a single-walled carbon nanotube (SWCNT)-functionalized electrochemical immunosensor with dielectrophoretic concentration. Nanomaterials. 13(6). Article 985. https://doi.org/10.3390/nano13060985.
Monterrosa, A., Joseph, S., Blaauw, B., Hudson, W., Acebes-Doria, A.L. 2022. Ambrosia beetle occurrence and phenology of Xylosandrus spp. (Coleoptera: Curculionidae: Scolytinae) in ornamental nurseries, tree fruit, and pecan orchards in Georgia. Environmental Entomology. 51(5):998-1009. https://doi.org/10.1093/ee/nvac064.
Illan, J.G., Walgenbach, J.F., Acebes-Doria, A., Agnello, A.M., Alston, D.G., Andrews, H., Bergh, J., Bessin, R.T., Blaauw, B.R., Buntin, G., Burkness, E.C., Cullum, J.P., Daane, K.M., Fann, L.E., Fisher, J., Girod, P., Gut, L.J., Hamilton, G.C., Hilton, R., Hoelmer, K.A., Hutchison, W.D., Jentsch, P.J., Joseph, S.V., Kennedy, G.G., Krawczyk, G., Kuhar, T.P., Leskey, T.C., Nielsen, A.L., Patel, D.K., Peterson, H.D., Reisig, D.D., Rijal, J.P., Sial, A.A., Spears, L.R., Stahl, J.M., Tatman, K.M., Taylor, S.V., Tillman, P.G., Toews, M.D., Villanueva, R.T., Welty, C., Wiman, N.G., Wilson, J.K., Zalom, F.G., Zhu, G., Crowder, D.W. 2022. Evaluating invasion risk and population dynamics of the brown marmorated stink bug across the contiguous United States. Pest Management Science. https://doi.org/10.1002/ps.7113.