2013 IPM IL virus survey in Nepal Naidu Rayapati Associate Professor (Virology) Department of Plant Pathology Irrigated Agriculture Research and Extension Center Washington State University Prosser, WA 99350, USA

Background Plant Virus Global Theme (IPVDN) Project objective: - to identify economically important viruses affecting vegetables in target countries identified by USAID. Nepal is one of the priority countries for IPVDN activities USAID-Nepal Mission Associate Award for IPM IL - One of the activities is “Management of virus diseases impacting vegetable crops” in target regions of Nepal (priority areas - Banke and Surketh Districts).

Objectives of the 2013 survey Accurate identification of viruses is the first critical step for management of virus diseases Survey farmers’ fields in Banke and Surketh districts Collect samples from vegetable crops showing virus-like symptoms and test for known viruses Make a preliminary assessment based on test results and report findings to USAID Mission in Nepal Make recommendations and develop future plans

Activities conducted (May 17-23, 2013) Visited Nepalgunj and Surkhet areas (Naidu Rayapati & Amer Fayad) Coordinated by iDE and staff Met with iDE staff, DADO, NARC (Lalitpur, Surkhet, Nepalgunj) Visited farmers’ fields, collected and processed samples Briefed USAID Mission (Evan Meyer) Tested for known viruses at Washington State University Shared results via progress report with USAID Mission

Focus crops & viruses Mainly vegetables Tomato, peppers, various types of cucurbits, and other crops (yardlong beans and cowpeas) Visited select farmers fields, monitored for symptoms Collected samples from plants showing virus-like symptoms Blotted samples on FTA Classic Cards for virus testing Tested by molecular assays (PCR) for : - Potyviruses (seed- and aphid-transmitted) - Begomoviruses (whitely-transmitted) - Tospoviruses (thrips-transmitted) - Cucumber mosaic virus (seed- and aphid-transmitted) Cloning and sequencing for confirmation of virus(es)

Diagnosis by RT-PCR/PCR Detection of viruses from FTA ® Classic Cards

Visit with farmers in Surkhet

Chilli peppers - Surkhet Chilli veinal mottle virus

Chilli peppers - Surkhet ‘Symptoms’ due to thrips feeding damage

Tomato - Surkhet Two viruses - highly similar to: Tomato leaf curl New Delhi virus Bean common mosaic virus

Cowpea - Surkhet Bean common mosaic virus

Squash - NARC-ARS, Dasharathpur, Surkhet Zucchini yellow mosaic virus

Pumpkin-Nepalgunj Zucchini yellow mosaic virus

Cucurbits -Nepalgunj A cucurbit field devastated by virus

Source of seed ??

Beans - Lalitpur Bean yellow mosaic virus

2013 Survey results – A summary AreaCropVirus Cucurbitaceous crops: SurkhetPumpkinZucchini yellow mosaic virus SurkhetSquashZucchini yellow mosaic virus NepalgunjBottle gourdZucchini yellow mosaic virus NepalgunjPumpkinZucchini yellow mosaic virus Solanaceous crops: SurkhetChilli pepperChilli veinal mottle virus SurkhetTomatoTomato leafcurl New Delhi virus Leguminous crops: SurkhetCowpeaBean common mosaic virus LalitpurBeansBean yellow mosaic virus Distinct viruses are present in vegetable crops surveyed

Symptom-based diagnosis of a virus disease is not always reliable Symptoms are variable due to: - crop species & cultivar - strain of a virus - age of the crop - environmental conditions - mixed virus infections - symptomless infections Different viruses can produce similar symptoms - mosaic symptoms - necrotic symptoms Accurate identification of a virus is critical Issues for further consideration

Identification of viruses based on symptoms is not always reliable – apply modern diagnostic methods. - Serological (ELISA, TBIA) and molecular (PCR) Continue surveys for identification of viruses towards building a comprehensive data base of viruses affecting vegetable crops grown in Nepal. Impacts of virus diseases on food & nutritional security (yield, nutritional quality and impacts on family income) Suggestions for action plans

Outreach/education programs for increased awareness of plant virus diseases spreading via seeds and by insect vectors. Strengthening capacity building programs to empower stakeholders and national research programs in dealing with virus diseases in vegetable crops. Research towards developing strategies for management of seed-borne and insect-transmitted virus diseases benefiting subsistence farmers in Nepal. Training the next generation of scientists/researchers (short-, medium-, & long-term-training, and curriculum improvement in academic programs) Collaborations are the key Suggestions for action plans

Thanks to: iDE-Nepal NARC