Page Banner

United States Department of Agriculture

Agricultural Research Service

Research Project: POSTHARVEST TREATMENT OF TROPICAL COMMODITIES FOR QUARANTINE SECURITY, QUALITY MAINTENANCE, AND VALUE ENHANCEMENT
2008 Annual Report


1a.Objectives (from AD-416)
To develop and protect export markets for tropical fruit, vegetable, nut, and ornamental crops, with emphasis on expanding and diversifying agriculture and agricultural exports in Hawaii by providing environmentally sound, economically viable systems, treatments, or processes that control quarantine pests, ensure product quality and food safety, and increase product value. The three broad objectives to be addressed include (1)Develop new or improved postharvest treatments, including alternatives to methyl bromide fumigation, for fruit, vegetable, and ornamental crop imports and exports to ensure security against quarantine pests; (2) Develop new or improved postharvest treatments for fruit, vegetable, nut, and ornamental crops to improve product quality and shelf life, reduce or eliminate postharvest disorders or decay, and enhance product value; and (3) Identify, develop or improve preharvest methods for fruit, vegetable, nut, and ornamental crops that enhance postharvest quality and reduce the incidence of quarantine pests that limit exports.


1b.Approach (from AD-416)
Develop target quarantine pest and host commodity control efficacy and product quality data, respectively, using irradiation, controlled-atmosphere temperature treatment, limonene and oils, ozone fumigation, or radio frequency treatment with commodity quality, microbial, biochemical, physical property, or vitamin analyses to meet Objectives 1 and 2; and measure target pest feeding activity to forecast damage, determine insecticide resistance levels, or develop caffeine-based toxicants to meet Objective 3. Foremrly 5320-43000-009-00D (4/05).


3.Progress Report
Research conducted under this project addresses quarantine pests or quality issues specific to exported tropical commodities vital to the growth of agriculture in the U.S. Pacific Basin. The project supports NP 304 Crop Protection and Quarantine Action Plan Components IV: Postharvest, Pest Exclusion, and Quarantine Treatment and V: Sustainable Pest Control Technologies, and NP-306 Quality and Utilization of Agricultural Products Action Plan Component I: Quality Characterization, Preservation, and Enhancement. In the area of quarantine treatment research, irradiation doses for white peach scale and coconut scale were approved and published by APHIS, which may allow a reduction from the generic treatment dose of 400 Gy to 150 Gy for papaya and banana. Ants are frequent hitchhiker pests on exported Hawaii fruits and vegetables; research suggested an irradiation dose of 100 Gy is sufficient to sterilize big-headed ant queens. Preliminary research results for green scale (an occasional pest on banana and flower crops) indicates that a dose of less than 150 Gy may be sufficient to sterilize this pest. The irradiation dose for treating sweet potatoes before export was lowered from 400 Gy to 150 Gy with minimal cutting and inspection for ginger weevil, which reduced treatment costs by more than half. The radiotolerance of dragonfruit was determined. This research supports rapid adoption of a final APHIS rule, and will expand specialty fruit exports from Hawaii. Efficacy tests with ozone fumigation demonstrated that coffee leaf rust urediniospores on green coffee berries were very susceptible to treatment, and that ozone fumigation could ensure quarantine security for green coffee imported into Hawaii. Preharvest research for quarantine pests included a field and packinghouse survey for ginger weevil, a quarantine pest of sweet potato. The survey showed that this insect is not present in the main production areas. Host range testing (in quarantine) of Encarsia diaspidicola, an imported biological control agent against white peach scale, indicated that the wasp is highly specific and therefore is a good candidate for field release. Attractant chemicals for the banana moth were field tested, and mating disruption trials in an abandoned papaya plantation are underway. The results have potential for controlling populations of this pest in coffee, pineapple and Dracaena. Postharvest research to improve product quality or extend shelf-life included progress in developing a maturity index for ‘Sharwil’ avocado fruit that can be used to define optimal harvest and export windows; and progress in developing modified atmosphere packaging of longans and rambutans as a component of an optimal system for maintaining export quality. For macadamia nuts, research that supports industry efforts to compete globally based on premium quality nuts included: identifying cultivars with superior oxidative stability and phytochemical composition, and determining roasting temperatures that eliminate Enterobacter cloacea, the cause of gray kernel disease of macadamia nuts.


4.Accomplishments
1. Dragon fruit tolerant of irradiation quarantine treatment

USDA-APHIS has recently issued a final rule for irradiated dragon fruit shipment from Hawaii, but until now, fruit tolerance of the quarantine treatment was unknown. Dragon fruit is a high-value, exotic tropical fruit grown for local consumption in Hawaii, but has potential to supply U.S. mainland markets. Dragon fruit is a host for fruit flies, and therefore subject to quarantine restrictions. ARS scientists in Hilo, Hawaii established that irradiation treatment of dragon fruit at doses < 800 Gy would ensure visual and compositional quality while providing quarantine security. This research will support rapid adoption of the APHIS rule, and expand specialty fruit exports from Hawaii.

(NP 304 Crop Protection and Quarantine Action Plan Component IV Postharvest, Pest Exclusion, and Quarantine Treatment. Problem being addressed: b) Exclusion of Exotic Insect Pests and Quarantine)

2. Survey fails to find ginger weevil in sweet potatoes

Fijian ginger weevil is a quarantine pest of sweet potatoes exported from Hawaii to the U.S. Mainland. Regulations require a 2% inspection for ginger weevil and radiation treatment at 400 Gy if this weevil is present. Otherwise sweet potatoes can be irradiated at 150 Gy for the other quarantine pests at a significant cost savings. A 2-year survey for ginger weevil in left-over sweet potato culls from rotated fields and from commercial shipments found no ginger weevils, suggesting this weevil is absent or extremely rare in areas where sweet potato is produced. As a result of the survey by ARS scientists in the Post-Harvest Tropical Commodities Research Unit in Hilo, HI, APHIS approved a reduced inspection requirement for ginger weevil in export shipments and sweet potatoes are routinely irradiated at 150 Gy.

(NP 304 Crop Protection and Quarantine Action Plan, Component IV Postharvest, Pest Exclusion and Quarantine Treatment. Problem being addressed: b) Exclusion of Exotic Insect Pests and Quarantine)

3. Identified a new pathogen on papaya fruit

Marketing fresh-cut and frozen papaya cubes has been limited by coliform bacterial counts of Enterobacter cloacae, which causes papaya internal yellowing disease. ARS scientists in Hilo, Hawaii identified and submitted a first report of a new pathogen on papaya (Enterobacter sakazakii) that causes abnormal internal yellowing symptoms. E. sakazakii is a cross-domain pathogen (plant and human pathogen), and therefore has the potential to affect the quality and food safety of papaya products.

(NP-306 Quality and Utilization of Agricultural Products Action Plan Component 1 Quality Characterization, Preservation, and Enhancement. Problem being addressed: 1d. Preservation and/or Enhancement of Quality and Marketability)

4. Native strains on Beauvaria identified

Beauveria bassiana is a fungal pathogen of insects which is commercially produced and used as a biopesticide for control of thrips, aphids, and whiteflies in greenhouses. Commercial strains of the fungus cannot be used in Hawaii because of quarantine restrictions. These restrictions are based on a concern that commercial strains of the fungus may threaten native insect populations. A study carried out in 2007 by ARS scientists in the Post-Harvest Tropical Commodities Research Unit in Hilo, HI demonstrates the genetic diversity of Beauveria bassiana strains already attacking insects in Hawaiian forests. Laboratory bioassays indicated that the virulence of strains already present in Hawaii was similar to the virulence of a strain found in a commercial Beauveria product. The results may lead to the deregulation of this fungus and the use of the commercial product as an ecologically friendly alternative to conventional insecticides for control of thrips, aphids, and whiteflies.

(NP 304 Crop Protection and Quarantine Action Plan, Component V: Sustainable pest control technologies)

5. First irradiation quarantine treatment study with an ant

Ants are common hitchhiker pests on tropical fruits exported from Hawaii. Irradiation is a commonly used quarantine treatment approved for exporting tropical fruits but no information was available on ant radiotolerance. ARS scientists in the Post-Harvest Tropical Commodities Research Unit in Hilo, HI demonstrated that the big-headed ant could be sterilized with an irradiation dose of 90 Gy. This was the first study suggesting an effective quarantine treatment for an ant.

(NP 304 Crop Protection and Quarantine Action Plan, Component IV Postharvest, Pest Exclusion and Quarantine Treatment. Problem being addressed: b) Exclusion of Exotic Insect Pests and Quarantine)

6. Limonene for controlling mealybugs and scale insects in ornamental crops

Mealybugs and scale insects are field and quarantine pests of ornamental exports from Hawaii. ARS scientists at Hilo, Hawaii successfully used 1% formulations of limonene (citrus peel oil) as an all-natural contact insecticide to control these pests. The ARS patents committee approved the discovery for patent protection and a CRADA partner is being sought to commercialize this new control method that will directly benefit the ornamental export industries of Hawaii by reducing field losses and export shipment rejections caused by mealybug and scale insects.

(NP 304 Crop Protection and Quarantine Action Plan Component IV Postharvest, Pest Exclusion, and Quarantine Treatment. Problem being addressed: b) Exclusion of Exotic Insect Pests and Quarantine)


5.Significant Activities that Support Special Target Populations
None


6.Technology Transfer

Number of Non-Peer Reviewed Presentations and Proceedings1
Number of Other Technology Transfer1

Review Publications
Follett, P.A. 2007. Postharvest phytosanitary radiation treatments: less-than-probit 9, generic dose, and high dose applications. In: M.J.B Vreysen, A.S. Robinson and J. Hendrichs (eds.), Area-Wide Control of Insect Pests: From Research to Field Implementation. Dordrecht, The Netherlands: Springer. p. 425-434.

Follett, P.A., R. Tom, D. Alontaga, E.D. Weinert, D.M. Tsuda, K.M. Kinney. 2007. Absence of the quarantine pest Elytroteinus subtruncatus in east Hawaii sweet potato fields. Proc. Hawaiian Entomol. Soc. 39: 33-38.

Follett, P.A., G. Taniguchi. 2007. Effect of irradiation on longevity and reproduction of Pheidole megacephala (Hymenoptera: Formicidae) queens. Proc. Hawaiian Entomol. Soc. 39: 43-47.

Follett, P.A. 2008. Effect of irradiation on Mexican leafroller (Lepidoptera: Tortricidae) development and reproduction. J. Econ. Entomol. 101: 710-715.

Neven, L.G., Follett, P.A., Raghubeer, E. 2007. Potential for High Hydrostatic Pressure Processing to Control Quarantine Insects in Fruit. Journal of Economic Entomology. 100(5):1499-1503.

Wright, M., Follett, P.A., Golden, M. 2007. Long-term patterns and feeding sites of southern green stink bug (Hemiptera: Pentatomidae) in Hawaii macadamia orchards, and sampling for management decisions. Bull. Entomol. Res. 97:569-575.

Neumann, G., R.G. Hollingsworth, P.A. Follett. 2007. First Record of the Hawaiian endemic scale, Colobopyga pritchardiae (Hemiptera: Halimococcidae), on the Big Island. Proc. Hawaiian Entomol. Soc. 39: 39-41.

Hollingsworth, R.G., Follett, P.A. 2007. Ionizing radiation for Quarantine Control of Opogona Sacchari (Lepidoptera: Tineidae). Journal of Economic Entomology. 100:1519-1524.

Hollingsworth, R.G., L.L. Loope. 2007. Learning from quarantine successes. Proc. Hawaiian Entomol. Soc. 39: 57-61.

Wall, M.M. 2008. Quality of postharvest horticultural crops after irradiation treatment. Stewart Postharvest Review (online) 2:1. Available from: http://www.stewartpostharvest.com/Vol4_2008/April_2008/Wall.htm

Nishijima, K.A., Wall, M.M., Siderhurst, M.S. 2007. Demonstrating pathogenicity of Enterobacter cloacae on macadamia and identifying associated volatiles of gray kernel of macadamia in Hawaii. Plant Dis. 91:1221-1228.

Kleitz, K.K., M.M. Wall, C.L. Falk, C.A. Martin, M.D. Remmenga, S.J. Guldan, 2008. Stand establishment and yield potential of organically grown seeded and transplanted medicinal herbs. HortTechnology. 18:116-121.

Kartika, H., Q.X. Li, M.M. Wall, S.T. Nakamoto, and W.T. Iwaoka. 2007. Major phenolic acids and total antioxidant activity in mamaki leaves, Pipturus albidus. Journal Food Science 72:S696-S701.

Keith, R.C., K.A. Nishijima, L.M. Keith, M.M. Fitch, W.T. Nishijima, M.M. Wall. 2008. Atypical internal yellowing of papaya fruit in Hawaii caused by Enterobacter sakazakii. Plant Disease. 92:487.

Souza, E., Follett, P.A., Price, D., Stacy, E. 2008. Field Control of the Invasive Ant Wasmannia auropunctata (Hymenoptera: Formicidae) in a Tropical Fruit Orchard in Hawaii. J. Econ. Entomol. 101:1068-1074.

Last Modified: 10/20/2014
Footer Content Back to Top of Page