A SUPERHERO WITHOUT A CAPE: USING THE COVER CROP SUNN HEMP TO FEED THE SOIL, SUPPRESS NEMATODES, AND SMOTHER WEEDS.

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 0209059
• Project Start Date: Nov 1, 2006
• Project End Date: Sep 30, 2012
• Program Code: [(N/A)]- (N/A)

Recipient Organization
UNIV OF HAWAII
3190 MAILE WAY
HONOLULU,HI 96822

Performing Department
Plant & Environmental Protection Sciences

Non Technical Summary
There is a need to develop pest management tactics that are comprehensive and can protect farmers from economic hardship that arises when multiple pest complexes (i.e., insects, nematodes, weeds) plague their crops. The long-term goals of our research partnership are to provide farmers a multidisciplinary, sustainable approach to pest management that concurrently targets multiple pest organisms.

Animal Health Component

(N/A)

Research Effort Categories

Basic

(N/A)

Applied

(N/A)

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
211	1421	1130	40%
212	1421	1120	40%
213	1421	1140	20%

Knowledge Area
212 - Pathogens and Nematodes Affecting Plants; 211 - Insects, Mites, and Other Arthropods Affecting Plants; 213 - Weeds Affecting Plants;

Subject Of Investigation
1421 - Cucumber;

Field Of Science
1120 - Nematology; 1130 - Entomology and acarology; 1140 - Weed science;

Keywords

sustainable

cover crop

sunn hemp

plant parasitic nematodes

weeds

insect pests

Goals / Objectives
The overall goal of the proposed study is to use a sunn hemp (Crotalaria juncea L.) cover crop to enhance soil nutrition and suppress nematodes, weeds, and insect-vectored plant viruses. Cucumber will be used as a model crop during these studies. However, the strategic approach defined in the proposed study may also be applied to other cropping systems. Our specific research objectives are to: 1. Determine the impact of sunn hemp on populations of key insect and nematode pests and insect-caused plant impairments (i.e., virus infections). 2. Assess the effect of cover cropping on the enhancement of beneficial organisms. 3. Quantify the impact of cover crop systems on vegetable productivity and marketable yields. 4. Determine the effect of cover crop systems on weed populations 5. Deliver an integrated, sustainable, and economically viable cover crop system to growers and educators.

Project Methods
Extension and Research Integration - Field studies and demonstration plots will be established at a commercial grower fields in Oahu, HI. Sunn hemp (C. juncea cv. Trophic Sun, seeded at 40 kg/ha) will be planted and irrigated for approximately 3 months during the summer (June-August) in each of four 14 m x 14 m plots. In addition, four fallow plots without cover crops will be used for monoculture plantings. In September, eleven 61 cm wide sunn hemp strips will be incorporated into the soil as a green manure at 1.2 m intervals in each cover crop plot. Sunn hemp will be mowed before being strip incorporated and those clippings not incorporated will be left on the soil as a surface mulch. After one week, cucumber will then be transplanted into the incorporated strips. Data will be collected on nematode and insect pest population densities, plant and soil nutrient status, cucumber marketable yields, and weed density and biomass. All data collected will be compared between cucumber-sunn hemp and cucumber monoculture plots.

Progress 11/01/06 to 09/30/12

Outputs
OUTPUTS: Throughout the 6 years, Sunn hemp Superhero Project progresses from promoting the use of sunn hemp in a strip-till cover cropping practice alone to integrate with solarization, vermicompost, mix-cover cropping with oat, to use of sunn hemp in no-till planting, mix-cover cropping with rapeseed, and integrate with Korean Natural Farming practice in 2012. Overall, this project generated 6 peer review articles, and an additional one submitted recently. This project partially support one Ph.D. student graduated from Department of Plant and Environmental Protection Sciences in 2011. In addition, this project also generated 3 CTAHR Cooperative Extension articles, and 9 HanaiAi, UH Sustainable and Organic Program Quarterly news articles. In average, one extension field day was hosted every year from 2008 to 2012 to show case results of this project to NRCS agents, CTAHR extension personnel, farmers, master gardeners and some students. We demonstrated the benefits of sunn hemp in enhancing soil nutrient recycler (soil mesoarthropods, free-living nematodes), suppressing plant-parasitic nematodes (by releasing allelopathic compounds), and enhancing natural enemies of plant-parasitic nematodes (nematode-trapping fungi) when use as surface mulch or till into soil. We also demonstrated that when using sunn hemp to intercrop with cash crops such as zucchini, sunn hemp serve as trap crop to reduce silver leave whitefly damage on zucchini, and attract alternative pollinators (carpenter bees, sweat bees, leaf cutter bees) into agroecosystem. Through our laboratory study on the allelopathic effect of sunn hemp, we determine the minimum sunn hemp incorporation rate to suppress plant-parasitic nematodes. We also improve understanding on how age and different tissue part of sunn hemp affect its allelopathic effect. Most recently, we demonstrated that integrating sunn hemp with Korean Natural Farming allow farmers to produce similar yield of grape tomato compared to that fertilized with organic fertilizer (chicken pellets 4-2-2). Since the initiation of this hatch project in 2006, the PI received 7 extramural grants branching out from this sunn hemp project (NRCS CIG, EPA, WSARE, TSTAR, OREI, ORG). The PI also created a website to summarize all grants and publications generated from this project at http://www.ctahr.hawaii.edu/WangKH/cover-crop.html. A YouTube video is produced at http://www.youtube.com/user/HIsustainAg. Two papers were delivered at National Conferences. PARTICIPANTS: Dr. K-H. Wang (PI). Nematologist/Soil Ecologist, Department of Plant and Enviromental Protection Sciences (PEPS), University of Hawaii at Manoa. [e-mail] Dr. C.R.R.Hooks (consult with insect monitoring protocol). Entomologist, Department of Entomology, University of Maryland. [e-mail] Dr. B. S. Sipes (assist and provide facilities for nematode analysis). Nematologist, Department of PEPS, University of Hawaii at Manoa. [e-mail] Jari Sugano (organize workshop, disseminate information, refer farmers in need to collaborate in the project). Ass. Extension Agent, PEPS, University of Hawaii at Manoa. [e-mail] Steve Fukuda (organize workshop, disseminate information, referring farmers in need to collaborate in the project). TPSS Wahiawa Extension Office, University of Hawaii at Manoa. [e-mail] Sharadchandra Marahatta (graduate student, received 0.5 FTE salary during the summer of 2009; assist in Trial III and VI). Department of PEPS, University of Hawaii at Manoa. [e-mail] Dr. Angelo Loffredo (Assistant Researcher): conduct experiment on mix cover cropping of sunn hemp and oat, monitor nematode-trapping fungi. PEPS, University of Hawaii at Manoa. [e-mail]. Dr. Theodore Radovich (Associate Professor) Horticulturist, TPSS, University of Hawaii at Manoa. Collaborate on integrating sunn hemp cover cropping with vermicompost tea treatment; no-till farming with roller crimper at Waimanalo Station. Collaborator: Milton Agader. Twin Bridges Farm, Waialua. Tel: [phone] Khamphout Chandara, Khamphout Farm, Kunia, Oahu. Tel:[phone] Owen Kanishiro, Kanishiro Farm, Waianae, Oahu. Tel:[phone] Rick Tamanaha, Kaleikoa Farm, Kaulapuu, Molokai. [e-mail] Susan Migita (Farm Manager) and Farm Crews at the Poamoho Experiment Station, Oahu. Tel: [phone] TARGET AUDIENCES: Vegetable crop farmers throughout Hawaii, Natural Resources and Conservation Services (NRCS) agents, County Extension Agents, Private Crop Consultants, Master garderners, educators, public audience online. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
The main outcome of our efforts is that more farmers are aware of the benefits of SH for soil-born pest suppression and soil health management. Currently there are at least two local seed stores where sunn hemp seeds can be purchased (Oahu RC&D) and one in Molokai. Both seed source said that the demand of sunn hemp seeds is higher than what they can supply. Our studies on sunn hemp provided several basic information needed for growers to do decision making. Results from several of our field trials demonstrated that SH cannot grow well in soil with pH< 5 (Wang et al., 2011 HanaiAi V8). Thus, soil pH need to be adjusted in acidic area. The graduate student involved in this project demonstrated that SH suppressed reniform nematodes more efficiently when the nematode is in its vulnerable stage (non-anhyrobiotic stage) (Marahatta et al., 2012; Nematropica 42: 34-40). This result implementing that the farmers should plant sunn hemp soon after termination of their previous nematode susceptible crop before the nematode turn into survival stage. Although our laboratory results showed that 2.5% w/w incorporation of sunn hemp residues into soil could suppress up to 90% of root-knot nematode population, our field sunn hemp biomass record showed that this might not be a biomass (equivalent to 12.5 tons dry biomass/acre) easily be achieved in many area. However, a common sunn hemp biomass generated in Hawaii (with pH > 5.5) if planted at 30 lb seeds/acre for two months between April and September is 5 tons dry biomass/acre. This is equivalent to 1% w/w of sunn hemp residues in soil. At 1% rate, sunn hemp can suppress 60% of root-knot nematode viability (Wang et al., 2012 HanaiAi V12). Farmers and extension agents find this valuable information for them to decide when to plant sunn hemp for plant-parasitic nematode management. Soil conservationists from NRCS use our information to promote the planting of sunn hemp cover crop (Susan Kubo, Bob Joy et al.). Our demonstration on integration of sunn hemp with vermicompost tea drenching (Wang and Radovich, 2012) or Korean Natural Farming expedite soil health improvement of sunn hemp from two cropping seasons to within one cropping season is encouraging as conventional believe is that it often take several cropping cycle to see true benefits of organic farming on soil health improvement. However, our results from integration of sunn hemp with solarization did not show additional benefits from sunn hemp alone except for better weed suppression. Integration of sunn hemp with oat also did not further improve soil health condition. Their impact on nematode-trapping fungi showed promising results but need further data collection which is on-going with our TSTAR project.

Publications

• Marahatta, S. P., Wang, K.-H. , Sipes, B.S., and Hooks, C.R.R. 2012. Effects of the integration of sunn hemp and soil solarization on plant-parasitic and free-living nematodes. Journal of Nematology 44: 72-79.
• Marahatta, S. P., Wang, K.-H., Sipes, B.S., and Hooks, C.R.R. 2012. Effects of Crotalaria juncea on anhydrobiotic state of Rotylenchulus reniformis. Nematropica 42: 34-40.
• Wang, K.-H., Duponte, M., and Chang, K. 2012. Use of Korean Natural Farming for vegetable crop production in Hawaii. HanaiAi Newsletter. December-January-February 2013.
• Wang, K.-H. and Radovich, T. 2012. Organic No-Till Farming with Roller Crimper. HanaiAi Newsletter. December-January-February 2013.
• Wang, K.-H. 2012. The secret of the allelopathic effect of sunn hemp for suppressing plant-parasitic nematodes. HanaiAi Newsletter March-April-May 2012. http://www.ctahr.hawaii.edu/sustainag/news/articles/V12-Wang-Allelopa thic.pdf
• Wang, K.-H. 2012. Cover crops as insectary plants to enhance above and below ground beneficial organisms. HanaiAi Newsletter March-April-May 2012. http://www.ctahr.hawaii.edu/sustainag/news/articles/V11-Wang-insectar y-covercrops.pdf.

Progress 10/01/10 to 09/30/11

Outputs
OUTPUTS: This year we took several approaches to improve the benefits of sunn hemp (SH) cover cropping for vegetable crop production. We integrated SH cover cropping with other sustainable pest management strategies, and also determine if soil incorporation of SH at the vulnerable stage of the plant-parasitic nematodes could kill nematode pest better. Nine field trials conducted include 1) trials at the Poamoho Experiment Station by mix planting of SH and oat in a conservative tillage system to enhance nematode-trapping fungi; 2) a trial were conducted at Khamphoute Farm, Kunia to test the benefits of integrating SH with soil solarization (Sol) in eggplant agroecosystem for nematodes and weeds control; 3) field trials at the Whitmore Experiment Station to study impacts of SH+Sol on reniform nematodes and to monitoring the long-term impact of SH+Sol on pineapple yield; 4) SH cover cropping in papaya orchards in Molokai and Kahuku; 5) greenhouse trials to examine if SH suppressed reniform nematodes better if the nematodes were in their vulnerable stage; 6) field trials at Waialua to examine the impact of integrating SH with crimson clover cover cropping on natural pollinators and also to examine the benefits of integrating cover cropping with compost tea treatment on soil health. We also collaborated with the University of Maryland on cover crop projects in no-till farming system by using nematodes community analysis as soil health indicators. Recently, we purchased a roller-crimper assembly, an invention by the Rodale Institute to make organic no-till practice possible. This will allow us to do no-till sunn hemp cover crop demonstration trial in Hawaii. We also conducted lab assays of the allelopathic effect of sunn hemp on root-knot nematodes based on plant age and plant tissues. We presented 4 outreach activities: Extension talks: 1)Wang, K.-H. Emerging strategies for controlling plant-parasitic nematodes organically. HOFA Annual Conference. 21 October, 2011. Attendance: 75(http://www.ctahr.hawaii.edu/sustainag/workshop/HOFA-Oct2011.html); 2)Wang, K.-H. Is mix planting of high and low C: N ratio cover crops beneficial CTAHR/ NRCS Extension-Research Update. April 20, University of Hawaii at Manoa, Honolulu; April 21, 2011 Waimanalo, HI. Attendance: 62. Field day/Exhibition:1)Wang, K.-H., L. Kaufman, T. Radovich, and J. Sugano. Strip-till cover cropping and compost tea workshop. Twin Bridges Farm, Waialua, HI. 19 May, 2011. Attendance: 26. 2)Wang, K.-H., J. Uchida and PEPS students. Worms and germs, friends or foes. Leeward Community College Yearly Science Fair Event. Nov 5, 2011 (estimate > 300 attendance). PARTICIPANTS: Dr. K-H. Wang (PI). Nematologist/Soil Ecologist, Department of Plant and Enviromental Protection Sciences (PEPS), University of Hawaii at Manoa. [e-mail] Dr. C.R.R.Hooks (consult with insect monitoring protocol). Entomologist, Department of Entomology, University of Maryland. [e-mail] Dr. B. S. Sipes (assist and provide facilities for nematode analysis). Nematologist, Department of PEPS, University of Hawaii at Manoa. [e-mail] Jari Sugano (organize workshop, disseminate information, refer farmers in need to collaborate in the project). Ass. Extension Agent, PEPS, University of Hawaii at Manoa. [e-mail] Dr. T. Radovich (assist in compost tea preparation). Sustainable Agriculturist. Department TPSS, University of Hawaii at Manoa. [e-mail] Sharadchandra Marahatta (graduate student before Aug, 2011), Department of PEPS, University of Hawaii at Manoa. [e-mail] Collaborator: NRCS agents (Nicola Giardina, Cynthia Stiles, Shirley Nakamura, Adam Reed et al.) Milton Agader. Twin Bridges Farm, Waialua. Tel: [phone] Khamphout Chandara, Khamphout Farm, Kunia, Oahu. Tel:[phone] Owen Kanishiro, Kanishiro Farm, Waianae, Oahu. Tel:[phone] Rick Tamanaha, Kaleikoa Farm, Kaulapuu, Molokai. [e-mail] Farm Crews at the Poamoho Experiment Station, Oahu. Tel: [phone] Training provided: Ph.D. graduate program for Sharadchandra Marahatta in Tropical Plant Pathology Program of the Department of Plant and Environmental Protection Sciences. Graduated in Summer 2011. Post doctorate associate, Angelo Loffredo, was recently hired to work on the nematode-trapping fungi project in SH and Oat cover cropping system. TARGET AUDIENCES: This project is to encourage conventional vegetable or fruit crop farmers, organic farmers (through HOFA, Hawaiian Organic Farmers Association; NRCS, CTAHR Extension), and low income immigrant farmers in Hawaii to adopt sunn hemp cover cropping or other soil health management approaches in their farming system. Information about sunn hemp cover cropping is also distributed to home gardeners, high school teachers, and a family event at Leeward community college. On line articles, you-tube video and weblinks are to target wider audiences that we could not reach during our outreach activities. We also prepared a postcard, Sunn hemp as a cover crop or green manure for your farm, with information linked to CTAHR extension article and You Tube video related to description of sunn hemp. This post card is distributed to all CTAHR extension agents throughout the state, as well as few local sunn hemp seed distributors in Hawaii. PROJECT MODIFICATIONS: The sunn hemp superhero project is modified to integrate sunn hemp cover cropping with compost tea treatment. Literature reviews and previous projects by the PI showed that enhancement of beneficial nematodes higher in the soil food web hierarchy took at least two cropping cycles. We were able to enhance predatory nematodes in one cropping cycle if we drench the soil with compost tea. Farmers will be more likely to adopt this practice if they can see a fast return of this soil health management tactics. Our greenhouse study and in vitro allelopathic assay also help us understand how to use SH more efficiently.

Impacts
The new outcome of this year project is further improvement of the benefits of sunn hemp by integrating with various sustainable farming practices. Intercropping sunn hemp with zucchini reduced the whiteflies visit to zucchini, thus a delay of silver leaves symptom. Zucchini fruit weight was 8.6 fold higher in SH than bare ground (BG). Although integrating sunn hemp with compost tea (chicken manure based) did not further improve soil health, use of compost tea suppressed initial numbers of plant-parasitic nematodes, and increased zucchini fruit yield compared to no tea. The tea also increase of predatory nematodes within one cropping cycle, which is encouraging as predatory nematodes normally required long time to be enhanced in conservation tillage system. In the same trial, we also determined that crimson clover is not a suitable cover crop in Hawaii due to its slow growth, poor flowering, and could not reseed rendering it from serving as a ground cover to enhance pollinators. Continuous planting of cucurbit crops in the same field over time could still result in heavy infestation of nematode pests despite periodical crop rotation with sunn hemp. Our greenhouse experiment demonstrated that sunn hemp allelopathic effect against plant-parasitic nematodes are most efficient if sunn hemp residues were soil incorporated when the nematodes are in vulnerable juvenile stage instead of in dormant or egg stages. This implies that planting sunn hemp after a long-term fallow period will not be effective in controlling plant-parasitic nematodes. Our sunn hemp allelopathic study indicated that sunn hemp was more suppressive to root-knot nematodes at 3- rather than 2- or 4 month-old. Flower tissue at 3-month old was most lethal to the nematodes. To achieve 100% kill of the nematode, 2.5% concentration of sunn hemp amendment is needed, which is rather high concentration (12.5 tons/acre) to achieve. A healthy stand of sunn hemp could generate approximately 5 tons dry biomass of sunn hemp/acre which is equivalent to 1%. This explains why sunn hemp cover cropping alone is not sufficient to suppress plant-parasitic nematodes. More nematode control strategies need to be integrated with sunn hemp cover cropping practice. After two cycles of mix-planting of SH and oat (O) with kabocha squash and cantaloupe, no significant difference in abundance of nematode-trapping fungi were observed among treatments. However, numbers of NTF increased over time in this conservation tillage practice. At the end of cover cropping in 2011, NTF tend to be more abundant in cover crop plots than in BG. Numbers of NTF dropped to undetectable level when soil was strip-till. We recently purchase a roller crimper which will allow no-till, which might provide more opportunities for NTF to establish. Overall, we generated 2 peer-review journal articles, 2 periodic newsletters, 5 conference presentations, 2 extension talks, 1 field day and 1 exhibition. We also received another new grant funding (from ORG as co-PI, looking at potential of integrating SH with rapeseeds) as a result of the basic information generated from this hatch project.

Publications

• Wang, K.-H. Use of nematode community ecology to develop emerging strategies for controlling plant-parasitic nematodes: avoiding the biological vacuum. 2011. 50th Annual Meeting of the Society of Nematologists Program and Abstracts Book, Oregon State University, Corvallis, OR. (P. 33).
• Wang, K.-H. and Zasada, I. Allelopathic effects of crotalaria spp. against M. incognita as affected by crop age, biomass, heat and species. 2011. 50th Annual Meeting of the Society of Nematologists Program and Abstracts Book, Oregon State University, Corvallis, OR. (P. 160).
• Wang, I.C., Wang, K.-H. and . Sipes, B. S. 2011. Development of a molecular method for nematode community analysis in Hawaii. 50th Annual Meeting of the Society of Nematologists Program and Abstracts Book, Oregon State University, Corvallis, OR. (P. 159).
• Wang, I.C., Wang, K.-H. and Sipes, B. S. 2011.Nematode community analysis for soil ecosystem health prediction. 2011 American Phytopathological Society Annual Meeting Program and Resource Book, Honolulu, HI (562-P).
• Marahatta, S.P., Wang, K.-H., and Sipes, B.S. 2011. Effects of Crotalaria juncea on the anhydrobiotic stage of Rotylenchulus reniformis. 50th Annual Meeting of the Society of Nematologists Program and Abstracts Book, Oregon State University, Corvallis, OR. (P. 106).
• Marahatta, S.P., Wang, K.-H., and Sipes, B.S. 2011. Integration of sunn hemp cover cropping and soil solarization for reniform nematode, Rotylenchulus reniformis, management. Phytopathology 101:S113.
• Wang, K.-H., Hooks, C.R.R., and Marahatta, S.P. 2011. Can using a strip-tilled living mulch system enhance organisms higher up in the soil food web hierarchy Applied Soil Ecology 49: 107-117.
• Wang, K.-H., Sipes, B.S., and Hooks, C.R.R. 2011. Sunn hemp cover cropping and solarization as alternatives to soil fumigants for pineapple production. Acta Hort (ISHS) 902: 221-232. http://www.actahort.org/books/902/902_22.htm.
• Newsletters: Wang, K.-H., Sipes, B.S., Hooks C.R.R., and Leary, J. 2011. Improving the status of sunn hemp as a cover crop for soil health and pests management. HānaiAi Newsletter Summer 2011. http://www.ctahr.hawaii.edu/sustainag/news/articles/V8-Wang-sunnhemp. pdf.
• Wang, K.-H. 2010. Why do organic farmers need to keep beneficial nematodes in their soil HānaiAi Newsletter Fall 2010. http://www.ctahr.hawaii.edu/sustainag/news/articles/V5-Wang-nematode. pdf.

Progress 10/01/09 to 09/30/10

Outputs
OUTPUTS: Approaches taken to improve sunn hemp (SH) cover cropping are: 1) to integrate SH with other pest management strategies; and 2) incorporating SH at the vulnerable stage of the plant-parasitic nematodes. Seven field trials were conducted: a) 2 field trials were conducted at the Poamoho Experiment Station to examine the use of SH, oat or their mixture in a conservation tillage system for soil health management; b) 1 field trial at Khamphoute Farm to test the benefits of integrating SH with soil solarization (Sol) in eggplant agroecosystem for nematodes and weeds control; c) 2 field trials of SH+Sol followed by cowpea were conducted at the Whitmore Experiment Station to study its impact on reniform nematodes; d) Continue to monitor the long-term impact of SH+Sol on pineapple yield; e) 2 commercial field trials of SH cover cropping in papaya orchards; f) 2 greenhouse trials conducted by a graduate student to examine if SH suppress reniform better if the nematodes are in their vulnerable stage; g) Collaborate with the University of Maryland on cover crop projects in no-till farming system by using nematodes community analysis as soil health indicators. Conference presentations:1)Wang, K.-H., C.R.R. Hooks, S. P. Marahatta, R. Manandhar. Use of a strip-till cover crop system to manipulate above and below ground organisms in cucurbit plantings. 2010 Meeting of the American Phytopathological Society (APS) at Charlette, NC. Aug 2010. 2)Marahatta, S. P., Wang, K.-H., and B.S. Sipes. An improvement in marigold cover cropping to suppress root-knot nematodes by targeting vulnerable stages. 2010 Society of Nematologists Conference, Boise, ID. July 2010.3)Wang, K.-H., B. S. Sipes, and C.R.R. Hooks. 2010. Sunn hemp cover cropping and solarization as alternatives to soil fumigants for pineapple production. 2010 International Pineapple Symposium, Persada, Johor Bharu, Malaysia. 07/13-15/2010. http://www.ishs-horticulture.org/workinggroups/pineapple/ Field day: Wang, K.-H., S. Fukuda, and J. Sugano. 08/05/2010. Strip-till cover cropping research update. University of Hawaii, Poamoho Experiment Station, Poamoho, HI. Extension talks: 1)Wang, K.-H. 2010. Nematode research program. 15/06/2010. CTAHR Road Show. Windward Community College, Kaneohe, HI. 2)Wang, K.-H. 2010. Non-chemical approaches for nematode management. 07-08/06/2010 Integrated Crop and Livestock Management Workshop, Komohana Extension and Research Center, Hilo, HI. 3)Wang, K.-H. and C.R.R. Hooks. 2010. Is your cover cropping practice benefiting A soil ecologist's point of view. 02/20/2010. 19th Annual MOFFA (Maryland Organic Farmers Association) Winter Meeting, Annapolis, MD. 4)Wang, K.-H. and C.R.R. Hooks. 2010. Does reduce pesticide use benefit soil health: A nematologist's point of view. 25/02/2010. Harford County Mid-Winter Educational Meeting, Deer Creek Overlook, 4-H Building, Street, MD. 5)Wang, K.-H. and C.R.R. Hooks. 2010. Use of nematodes and soil microarthropods as soil health bioindicators: a visit of Hawaii ecological based pest management projects. 26/02/2010. Entomology Colloquium, Department of Entomology, University of Maryland, College Park, MD. PARTICIPANTS: Dr. K-H. Wang (PI). Nematologist/Soil Ecologist, Department of Plant and Enviromental Protection Sciences (PEPS), University of Hawaii at Manoa. [e-mail] Dr. C.R.R.Hooks (consult with insect monitoring protocol). Entomologist, Department of Entomology, University of Maryland. [e-mail] Dr. B. S. Sipes (assist and provide facilities for nematode analysis). Nematologist, Department of PEPS, University of Hawaii at Manoa. [e-mail] Jari Sugano (organize workshop, disseminate information, refer farmers in need to collaborate in the project). Ass. Extension Agent, PEPS, University of Hawaii at Manoa. [e-mail] Steve Fukuda (organize workshop, disseminate information, referring farmers in need to collaborate in the project). TPSS Wahiawa Extension Office, University of Hawaii at Manoa. [e-mail] Sharadchandra Marahatta (graduate student, received 0.5 FTE salary during the summer of 2009; assist in Trial III and VI). Department of PEPS, University of Hawaii at Manoa. [e-mail] Collaborator: Khamphout Chandara, Khamphout Farm, Kunia, Oahu. Tel:[phone] Owen Kanishiro, Kanishiro Farm, Waianae, Oahu. Tel:[phone] Rick Tamanaha, Kaleikoa Farm, Kaulapuu, Molokai. [e-mail] Ken Kamiya, Kamiya Farm, BYU, Leia, Oahu. Tova Callender, Ulupono Sustainable Agriculture Development, Kapalua Farm,4900 Honoapi`ilani Hwy, Lahaina, HI 96761. Tel:[phone] Farm Crews at the Poamoho Experiment Station, Oahu. Tel: [phone] TARGET AUDIENCES: This project is to encourage conventional vegetable or fruit crop farmers, organic farmers (through HOFA, Hawaiian Organic Farmers Association), and low income immigrant farmers in Hawaii to adopt sunn hemp cover cropping in their farming system. Information about sunn hemp cover cropping is also distributed to home gardeners, high school teachers, and a family event at Leeward community college. On line articles, you-tube video and website links are to target wider audiences that we could not reach during our outreach activities. PROJECT MODIFICATIONS: The sunn hemp superhero project is modified to integrate sunn hemp cover cropping with soil solarization and row switching technique. This is to further improve the efficiency of sunn hemp cover cropping. Previously, sunn hemp cover cropping system focuses on using sunn hemp as a green manure crop or as living mulch. By integrating strip-till living mulch system with row switching, we are developing a novel cover cropping system for farmers to practice multiple cropping (several cycles of cash crops before rotating with cover crop or a fallow period) while planting cover crops. Many farmers are reluctant to adopt cover cropping due to sacrifice of farmland for two to three months to plant cover crop. We are testing this new cover cropping approach to encourage more cover cropping practice among Hawaiian farmers.

Impacts
A year-round solarization temperature scheme for Oahu is created based on field trials. To achieve a lethal heat unit to kill plant-parasitic nematodes (42C, minimum of 14 hours), solarization needs to be performed between April to October. Solarization performed during November to March accumulated 0 heat unit and will most likely fail to suppress nematodes and weeds. This information will help farmers to decide when to use solarization as an alternative strategy for soil-borne pests management. Our results did not support the hypothesis that SH+Sol would increase heat units accumulated than Sol alone. In some occasions where sunn hemp biomass was very abundant, SH+Sol did increase heat units, but Sol suppressed weeds and nematodes to the same level as SH+Sol. Participating farmers are most impressed with weed suppression from solarization. Results from various field trials demonstrated that SH cannot grow well in soil with pH< 5. Beside pineapple growers, most farmers are willing to adjust soil pH to grow SH. The main outcome of our extension efforts is that more farmers are aware of the benefits of SH for soil-born pest suppression and soil health management. This year, we have expanded the interest of farmer to use sunn hemp cover crops even in perennial cropping system: 2 papaya growers and a banana grower had requested SH seeds to grown in their orchard. In addition, farmers, extension and NRCS agents are most impressed with the use of nematode community analysis to show the improvement of soil health in our SH conservation tillage system. Two organic farms (from Molokai and Maui) had sign up to conduct conservation tillage cover cropping study in their farms. Some extension agents in Hilo wanted to use nematode community analysis to evaluate new soil health management products (e.g. IMO-4). Ulupono Initiative at Kapalua Farm in Maui asked for nematode community analysis as part of the information to develop a soil health management plan to turn over former Maui pineapple land into organic vegetable production. Our collaboration with University of Maryland focus on soil health analysis. This collaboration leads to additional three grant funding from NIFA-OREI (Organic Research and Education Initiative), Maryland Grain Producer Utilization Board, and Maryland Soybean Board. Maryland farmers learn that sunn hemp generated great amount of biomass during summer time in Maryland and provide a fast inputs of organic matters. The graduate student involved in this project demonstrated that SH suppressed reniform nematodes more efficiently when the nematode is in its vulnerable stage (non-anhyrobiotic stage). The student received a competitive travel award from the Society of Nematologiests to attend an annual meeting in Portland, OR and present this result. Overall, we generated 4 peer-review journal articles, 1 extension publication, 4 periodic newsletters, 3 conference presentations, 1 field day, and 5 extension talks. We also received two new grant funding (from EPA and NRCS) as a result of the basic information generated from this hatch project.

Publications

• McSorley, R. and K.-H. Wang. 2009. Possibilities for biological control of root-knot nematodes by natural predators in Florida soils. Proc. Fla. State Hort. Soc. 122:421-425.
• McSorley, R., D.R. Seal, W. Klassen, K.-H. Wang, and C.R.R. Hooks. 2009. Non-target effects of sunn hemp and marigold cover crops on the soil invertebrate community. Nematropica 39: 235-245.
• Wang, K.-H., B.S. Sipes, and C.R.R. Hooks. 2010. Environmental friendly approaches for managing nematodes and weeds on pineapple. Pineapple News 17: 27-32. May 2010. http://www.ishs-horticulture.org/workinggroups/pineapple/PineNews17.p df.
• Wang, K.-H. and C.R.R. Hooks. 2009. 2Strip-till cover cropping and row switching techniques. HānaiʻAi Newsletter Winter 2009. http://www.ctahr.hawaii.edu/sustainag/Downloads/Strip-till_row-switch ing.pdf.
• Wang, K.-H. 2010. Soil solarization and cover cropping as alternatives to soil fumigation for pineapple growers in Hawaii. HānaiʻAi Newsletter Spring 2010. http://www.ctahr.hawaii.edu /sustainag/news/articles/V3-Wang-SHPineapple.pdf.
• Wang, K.-H. 2010. Improving marigold cover cropping for nematode management. HānaiʻAi Newsletter Summer 2010. http://www.ctahr.hawaii.edu/sustainag/news/articles/V3-Wang-SHPineapp le.pdf.
• Wang. K.-H. and B.S. Sipes. 2009. Solarization and Cover Cropping as Alternatives to Soil Fumigants for Nematode Management in Hawaii Pineapple Fields. CTAHR Cooperative Extension Service SCM-29. 4 pp. http://www.ctahr.hawaii.edu/oc/freepubs/pdf/SCM-29.pdf.

Progress 10/01/08 to 09/30/09

Outputs
OUTPUTS: Six field trials were conducted; five of them at commercial farms whereas one of them at the UH Poamoho experiment station. Trial I was conducted from October to May at Benny's Farm in Lanai to demonstrate the use of sunn hemp cover crop and its integration with solarization for nematodes, weeds and soil health management for tomato production. Trial II was conducted at Ed Otsuji's Farm from April to July to demonstrate the use of sunn hemp to manage reniform nematodes on beet in Hawaii Kai, Oahu. Trial III was conducted at Khamphout Farm in Kunia, Oahu from July to March to compare sunn hemp vs marigold and bareground preplant treatments for management of nematodes and soil health on bitter melon. To extend the performance of sunn hemp treatment, we repeated the experiment again in the same field using sunn hemp + solarization and row switching techniques in eggplant agroecosystem. This demonstration was initiated in June and it is on going. Trial IV was conducted at Aloun Farm's pineapple field in Kunia, Oahu to demonstrate use of sunn hemp cover crop as green manure and for nematode management during the summer months from May to July. Trial V was initiated at Kaleikoa Farm, Kaulapuu, Molokai in September to demonstrate the use of sunn hemp as living mulch in papaya planting patch to suppress weeds, preserve soil moisture and enhance beneficial nematodes. Trial VI was conducted from January to August in Poamoho Experiment Station to examine sunn hemp as living mulch in a strip-till winter gourd cropping system for above (insect and weeds) and below (nematodes and soil-borne fungi) ground pest management. Dissemination: A workshop was held on 29 September 2009 at Waimanalo Experiment Station in collaboration with two other CTAHR extension specialists, Drs. Ted Radovich and James Leary. The workshop is co-organized by extension agents, Jari Sugano and Steve Fukuda and Associated Specialist that work with Hawaii underserved farmers, Dr. Sabina Swift. A total of 15 agricultural personnel attended the workshop. This participant encompassed farmers, other CTAHR extension agents, master gardeners, Syngenta representatives, and CTAHR graduate students and faculties (besides the organizers). A comprehensive handout was prepared for this workshop. It is now posted on CTAHR Sustainable and Organic Program website (http://www.ctahr.hawaii.edu/sustainag/Downloads/2009UpdatesSunnHempS uperhero.pdf). The new concept of sunn hemp cover cropping using strip-tilling and row switching approaches is also introduced online at http://www.ctahr.hawaii.edu/sustainag/Downloads/Strip-till_row-switch ing.pdf. PARTICIPANTS: Dr. K-H. Wang (PI). Nematologist/Soil Ecologist, Department of Plant and Enviromental Protection Sciences (PEPS), University of Hawaii at Manoa. [e-mail] Dr. C.R.R.Hooks (consult with insect monitoring protocol). Entomologist, Department of Entomology, University of Maryland. [e-mail] Dr. B. S. Sipes (assist and provide facilities for nematode analysis). Nematologist, Department of PEPS, University of Hawaii at Manoa. [e-mail] Jari Sugano (organize workshop, disseminate information, refer farmers in need to collaborate in the project). Ass. Extension Agent, PEPS, University of Hawaii at Manoa. [e-mail] Steve Fukuda (organize workshop, disseminate information, referring farmers in need to collaborate in the project). TPSS Wahiawa Extension Office, University of Hawaii at Manoa. [e-mail] Dr. James Leary (cooperate in workshop and field day events, set up sunn hemp trial in Molokai). Weed Scientist, Department of Natural Resources and Environment Management, Kula, Maui, HI. [e-mail] Sharadchandra Marahatta (graduate student, received 0.5 FTE salary during the summer of 2009; assist in Trial III and VI). Department of PEPS, University of Hawaii at Manoa. [e-mail] Dr. Wayne Brown (count beneficial microarthropods involved in soil nutrient cycling). Acarologist, Independent Biological Investigator. [e-mail] Collaborator: Khamphout Chandara, Khamphout Farm, Kunia, Oahu. Tel:[phone] Aloun Farm, Ewa Beach, Oahu. [phone] Alberta deJetley, Benny's Farm, Lanai City, Lanai. [e-mail] Rick Tamanaha, Kaleikoa Farm, Kaulapuu, Molokai. [e-mail] Ed Otsuji, Otsuji's Farm, Hawaii Kai, Oahu. [phone] Farm Crews at the Poamoho Experiment Station, Oahu. Tel: [phone] Training provided: 1.Wang,K.-H, J. Leary, T. Radovich, J. Sugano, S. Swift, S. Fukuda. Sunn hemp cover crop workshop and Waimanalo open house sneak preview. Waimanalo Experiment Station, Waimanalo, Oahu. September 25, 2009 (attendance 20). 2.Ph.D. graduate program for Sharadchandra Marahatta in Tropical Plant Pathology Program of the Department of Plant and Environmental Protection Sciences. 3.Five demonstration trials in commercial farms listed above. TARGET AUDIENCES: This project is to encourage conventional vegetable or fruit crop farmers, organic farmers (through HOFA, Hawaiian Organic Farmers Association), and low income immigrant farmers in Hawaii to adopt sunn hemp cover cropping in their farming system. Information about sunn hemp cover cropping is also distributed to home gardeners, high school teachers, and a family event at Leeward community college. On line articles, you-tube video and website links are to target wider audiences that we could not reach during our outreach activities. PROJECT MODIFICATIONS: The sunn hemp superhero project is modified to integrate sunn hemp cover cropping with soil solarization and row switching technique. This is to further improve the efficiency of sunn hemp cover cropping. Previously, sunn hemp cover cropping system focuses on using sunn hemp as a green manure crop or as living mulch. By integrating strip-till living mulch system with row switching, we are developing a novel cover cropping system for farmers to practice multiple cropping (several cycles of cash crops before rotating with cover crop or a fallow period) while planting cover crops. Many farmers are reluctant to adopt cover cropping due to sacrifice of farmland for two to three months to plant cover crop. We are testing this new cover cropping approach to encourage more cover cropping practice among Hawaiian farmers.

Impacts
Results: All demonstration trials showed that sunn hemp planted in spring, summer or fall generated significant amount of organic biomass and increase N content on wide range of crops planted subsequently. Sunn hemp as living mulch in our strip-till system consistently enhance below ground beneficial organisms (nematodes and microarthropods) involved in soil nutrient cycling. While sunn hemp as living mulch did not increase crop yield in the fist year (2008), it increased bitter melon growth and winter gourd yield in the second year (2009). However, sunn hemp living mulch tended to increase numbers of thrips and pickle worms on these crops. In the Lanai trial, sunn hemp not only increased soil N, but also increased soil Ca and Mg. Integration of solarization with sunn hemp further increase soil P content. In the Kunia Trial, integration of solarization with sunn hemp heat up top soil layer (0-10 cm) more efficiently than solarization alone. Solarization suppressed weeds densities significantly. Outcome: A workshop was conducted to summarize result outcomes from field trials. Two conference presentations were made by the PI and a graduate student. The graduate student received a second place award for his poster presentation at College of Tropical Agricultural Science (CTAHR) student symposium. A website for the PI was created (http://www.ctahr.hawaii.edu/sustainag/leaders/wang.html). A peer reviewed article and a newsletter article were published. Impacts: All participating farmers are adopting sunn hemp cover cropping. They learn that planting sunn hemp is a good solution to their nematode problem besides additional benefits in building up soil health. Farmers and master gardeners that attended the workshop received sunn hemp seeds for planting. A teacher at McKinley High School learns about sunn hemp through a student worked in our lab. She then requested sunn hemp seeds to demonstrate the use of cover crop in their high school agriculture project. Aloun Farm and Khamphout Farm received additional sunn hemp seeds to be planted in two additional acres of their farmland beside the demonstration plots. Aloun Farm had shown their interest to expand their sunn hemp planting after corn as soil after continuous planting of corn had shown nutrient deficiency despite regular fertilization. Alberta deJetley in Lanai is purchasing more sunn hemp seeds from Crop Care Hawaii, LCC for their farm and is participating in soil conservation program in NRCS EQIP Program. Rick Tamanaha in Molokai is convinced that planting of sunn hemp as ground cover can maintain soil moisture and will be a key to increase his organic papaya production in Molokai, a prime place for papaya production in Hawaii as it is located in a papaya ring spot virus-free zone. Many home gardeners like the idea of planting a crop to protect their vegetable crops or landscape plants from nematode damage. It is always a welcoming suggestion for them to plant sunn hemp in their garden.

Publications

• McSorley, R., K.-H. Wang, J.J. Frederick. 2008. Integrated effects of solarization, sunn hemp cover crop, and amendment on nematodes, weeds, and pepper yields. Nematropica 38: 115-125.
• Wang, K.-H, R. McSorley, R. N. Gallaher. 2009. Can nematode community indices elucidate plant health conditions Proceedings of 2009 Society of Nematologists and Soil Ecology Society Conference, Burlington, VM. P. 203 (abstract).
• Marahatta, S. P., K.-H. Wang, and B.S. Sipes. 2009. Effects of a strip-till cover cropping system on nematode communities. Proceedings of 2009 Society of Nematologists and Soil Ecology Society Conference, Burlington, VM. P. 141 (abstract).
• Wang, K.-H. and S. Marahatta. 2009. Improving sunn hemp superhero status by integrating with solarization. HānaiAi Newsletter (2009 September issue), CTAHR Sustainable and Organic Agriculture program. http://www.ctahr.hawaii.edu/sustainag/news/articles/V1-wang-solarizat ion.pdf

Progress 10/01/07 to 09/30/08

Outputs
OUTPUTS: University of Hawaii: Two field trials using sunn hemp (SH) and marigold (MG) as cover crops were compared to bare ground (BG) treatment. First trial was initiated in October 2007 at a Laotian farmer's farm, Khamphute Farm, Kunia, Oahu, HI. A cucurbit crop, bittermelon, was chosen based on preference of the grower. We are repeating this trial in summer of 2008. Second field trial was conducted at Poamoho Experiment Station, University of Hawaii. Cover crops were grown in May 2008 followed by a cucumber crop. We finished harvesting cucumber in October and the field is now prepared for second crop. Dissemination: On Oct 8, 2008, a field day was held at the Poamoho Experiment Station, University of Hawaii. Assisted by county extension agents, Jari Sugano and Steve Fukuda, PI Wang organized the field day. Six farmers, one Sustainable Agriculture faculty, one extension specialist, and a producer from Crotalaria Seed, Inc. attended the field day. A summary of the bittermelon trial and cucumber trial were presented in handouts with pictorial guide on the strip-till cover cropping practice. Extension articles and virtually field day videos on how to use sunn hemp or marigold as cover crops were distributed. Four attendees turn in evaluation forms. On Oct 18, 2008, a farmers' workshop organized by extension specialist, Dr. Sabina Swift, was conducted at Mililani Agricultural Park, Mililani, Oahu. The workshop was targeting at low income immigrant farmers. Twelve farmers attended the workshop. Most of these farmers lease their lands from Mililani Ag. Park and are beginning farmers that are very eager to learn new farming techniques. PI Wang presented "Cover crops for management of above and below ground pests and beneficial organisms in vegetable cropping system." Extension articles on sunn hemp and marigold were distributed. Seven farmers turn in evaluation forms (the other attendees are spouse of some attendees, thus did not turn in evaluation forms). Five of them are aware of the benefits of cover crop before the workshop. Only one farmer is aware of nematode being a problem in his farm. Six of them plan on using cover crops in their farm after this workshop, but all of them sign up to obtain sunn hemp seeds. All agree that it is important to enhance beneficial organisms in their farms. Six of them agree that using sunn hemp as a cover crop can reduce fertilizer cost. PARTICIPANTS: K-H. Wang, Department of Plant and Environmental Protection Sciences, University of Hawaii at Manoa. [e-mail]; C.R.R.Hooks, Department of Entomology, University of Maryland. [e-mail]; B.S. Sipes, Department of Plant and Environmental Protection Sciences, University of Hawaii at Manoa. [e-mail]; Jari Sugano, Asst. Extension Agent, PEPS, University of Hawaii at Manoa. [e-mail]; Steve Fukuda, TPSS Wahiawa Extension Office, University of Hawaii at Manoa. [e-mail]; Graduate student: Sharadchandra Marahatta, Department of Plant and Environmental Protection Sciences, University of Hawaii at Manoa. [e-mail]; Graduate student: Roshan Manandha, PEPS, University of Hawaii at Manoa. [e-mail]; Collaborator: Khamphout Chandara, Khamphout Farm, P.O. Box 970510, Waipahu, HI 96797 Poamoho Farm Crew TARGET AUDIENCES: Low income immigrant farmers in Oahu, HI Vegetable farmers in Hawaii PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
In the Poamoho trial, sunn hemp (SH) generated significant amount of dry plant biomass (4.65 tons/acre), contributing > 8,000 lb/acre of organic matter, 163 lb of total N /acre, 55 lb P/acre and 256 lb K/acre within 10 weeks of growth during summer. However, majority of the N is in organic form and will need to be decomposed for plants to uptake. At termination of cover crop, weeds in SH plots were less than that in bare ground (BG) and marigold (MG). SH and MG sustained lower number of reniform nematodes at cucumber harvest. In the Kunia trial, root-galls caused by root-knot nematodes were only lower in SH than BG, but not in MG at harvest. SH plots had higher numbers of bacteria and fungal feeding, and omnivorous nematodes than the BG control. MG and SH treated plots were richer in nematode taxa, whereas nematode diversity was highest in MG. Nematode fauna analysis revealed that SH was enriched with soil nutrients, whereas BG was dominated by fungal decomposition, a signal of stressful soil condition. There was also less soil micro-arthropods involved in soil nutrient recycling in BG than SH and MG. Numbers of thrip on cucurbit leaves were lower in cover crop treatments than in the BG in both trials. Numbers of thrip on cucurbit flowers were not different among treatments, but were higher towards crop harvest on SH in the Kunia trial. Both cover crops reduced whiteflies counts, but MG plots had highest counts of mites on cucumber leaves. Numbers of spider collected from pitfall traps were higher in MG earlier in the season, those in SH increased later in the season. Carabid beetles, natural enemies of many insect pests, were only found in MG. Sunn hemp mulch maintained a higher population of isopod throughout the season. No difference in bittermelon yield was detected among treatments in Kunia due to overly high pressure of fruit flies. In Poamoho, cucumber yield was higher in BG than cover crop treatments. Shading from the living mulch and competition from vigorous MG growth could contribute to this result. In addition, shade in MG and SH could also provide a niche for fruit flies. Higher percentage of fruit fly damage was observed in the cover crop treatments. Pickle worm damage varies from date to date, whereas thrips or mites damage was generally lower in SH plots. In conclusion, cover crops, especially SH, suppressed plant-parasitic nematodes, and enhanced a healthier soil ecosystem based on measurement of beneficial nematodes and soil microarthropods. SH and MG reduced whiteflies and thrips on cucurbit crops, but numbers of mites were higher in the MG treatment. SH and MG are not suitable living mulch in ecosystem where fruit flies pressure is high. Sunn hemp could be more suitable as organic mulch instead of living mulch to avoid the shading. Marigold could be used during fall to winter season where shorter day length will force the crop to senesce after cash crops were transplanted. The living mulch could serve as trap crops for fruit flies in conjunction with insecticide spray (GF120). Modification of the current cover crop strip-till system is being made in 2008-2009 trials to address challenges faced in these 2007-2008 trials.

Publications

• Hooks, C.R.R., K. Chandara, D. Fallon, K.-H. Wang, and R. Manandhar. 2007. The impact of sunn hemp cover cropping on belowground organisms and nutrient status associated with a cucumber planting. CTAHR Cooperative Extension Service SCM-21. 7pp.
• Wang, K.-H. and C.R.R. Hooks. 2008. Sunn hemp for soil health and nematode management. CTAHR/SARE Virtually Field day Video series. http://www.youtube.com/watchv=AG_CYsVmqN4
• Manandhar, R., Hooks, C.R.R., and M. G. Wright. 2008. Influence of cover crop and intercrop systems on Bemisia argentifolli (Hemiptera: Aleyrodidae) infestation and associated squash silverleaf disorder in zucchini. Economic Entomology (in press).

Progress 10/01/06 to 09/30/07

Outputs
OUTPUTS: Results and findings from the project are being disseminated through publications, farm site visits, website postings, conference presentations, communication with extension agents, and a field day event. To reach greater immigrant farm communities in Hawaii, the publication on using sunn hemp for nematode suppression was translated into four additional languages and handouts of the publication as well as a discussion of our work was presented to participants at a field day entitled "Benefits of cover cropping in agricultural fields". PARTICIPANTS: Dr. Hooks is the PI of the project and is involved in all aspects of the project but his greatest responsibility is the establishment of field plots, data collection and analysis, and familiarizing farmers with cover crop uses. A co-PI, Dr. Fallon conducted and supervised nematode sampling and identification, and data analysis. The co-PI, Dr. Wang helps with field design, and below soil sampling of pest and beneficial organisms, and other data collections. In addition to the PIs of the project, one graduate student participated in the project and contributed to several tasks related to the field experiments (e.g., land preparation, data collection, plot maintenance, and harvesting. A collaborating producer, Mr. Khamphout, is a small resource poor farmer who has close ties with several other farmers in Hawaii. He allows use of his land and farm hands for work being conducted on his farm. All participants with the exception of Mr. Khamphout are associated with the University of Hawaii at Manoa, Department of Plant and Environmental Protection Sciences. TARGET AUDIENCES: Individuals interested in organic farming and sustainable agricultural practices, small and midsize farms, and resource-challenged growers. Efforts to educate immigrant farmers.

Impacts
Prior to the start of this project, the collaborating producer and his caretakers did not have the ability to recognize plants infected by plant parasitic nematodes, specifically root-knot nematodes. Currently all of the workers on the producer farm are familiar with root-knot nematode damage. This alone resulted in lower production cost because fertilizers are now more judiciously applied. Further, the producer plans to start producing bitter melon. A crop that he discontinued growing because of perennial crop failure. No studies had been conducted in Hawaii to determine the impact of sunn hemp on nematodes, soil health and fertility, and crop plant nutrient levels concurrently. Thus, a field study was carried out to determine the effect of sunn hemp on these parameters. During these studies, cucumber plant stands and subsequent yields were greater in sunn hemp compared to bare-ground habitats. We have started promoting the use of sunn hemp as an alternative to chemical nematicides for nematode control. Farm visits are ongoing to familiarize growers with the use of sunn hemp and other cover crops as part of an integrated disease management program. We have noticed a significant jump in the number of growers interested in using sunn hemp on their farm. We are now in the early stages of evaluating sunn hemp as part of a double cropping system. In the pass, Hawaii growers were given limited information regarding the use of cover crops for nematode management and thus mainly relied on nematicides and crop rotation for their management. However, crop rotation is not an option for those farmers with limited land and/or who grow a few crops types, and all or most are susceptible to similar nematode species. Thus, sunn hemp offers an additional option. However, one of the leading constraints to greater adoption of sunn hemp and other sustainable practices into IPM programs for nematode management in Hawaii was the availability and dissemination of information. Through our collaborative research and outreach efforts, we have started to disseminate more information to stakeholders on nematode biology and how sunn hemp can be used as a sustainable option for their management. Since the start of the project, some growers have gained a better understanding of nematodes and the mechanisms by which sunn hemp and other cover crops can be used not only to suppress their population but increase soil health through the enhancement of beneficial soil organisms. We now expect to see a reversal in a dependency on chemical nematicides. Two extension publications have been published and posted at the college website and an additional publication detailing results of the field experiment has been submitted. Some of the work will also be presented at symposium at the upcoming Entomological Society of American meeting.

Publications

• Hooks, C.R.R, H.-H. Wang, and D. Falon 2006. An ally in the war against nematode pests: using sunn hemp as a cover crop to suppress root-knot nematodes. University of Hawaii at Manoa, College of Tropical Agriculture and Human Resources, Plant Disease Publication PD-32. www.cthar.hawaii.edu/oc/freepubs/pdf/PD-32.pdf
• Hooks, C.R.R, A. Fereres, and K.-H. Wang. 2007. Using protector plants to guard crops from non-persistent aphid-borne non-persistent viruses. University of Hawaii at Manoa, College of Tropical Agriculture and Human Resources, Insect Pest Publication IP-32. www.cthar.hawaii.edu/oc/freepubs/pdf/IP-32.pdf