As with other potato viruses, the best management method for TRV is to avoid introduction of the virus or its vector to your fields. Once the virus or its stubby root nematode vector has been detected, steps must be taken to avoid spreading these organisms to clean fields. The following steps can help to manage this disease.
- Avoid introducing TRV and stubby root nematodes onto your farm.
- Manage inoculum levels on your farm. Avoid spreading TRV and stubby-root nematodes from infested fields to clean fields.
- Plant potatoes strategically to reduce risk and the spread of disease.
- Use TRV-resistant cultivars strategically to reduce loss.
Avoid introducing TRV and stubby-root nematodes onto your farm.
- Do not plant symptomatic seed. Inspect seed for lesions and necrosis. If possible, obtain seed from areas where TRV has not been detected.
- Do not allow contaminated equipment onto your farm. Clean and sanitize all machinery and vehicles that may have come into contact with TRV infested soils before it comes onto your farm. Don’t forget to include equipment belonging to temporary help. Follow the same procedures when borrowing or leasing used equipment.
- Avoid manure and compost from contaminated sources. Ensure that the materials you use from outside sources do not originate from contaminated materials, such as potato debris and culls.
- Do not plant other potentially infected crop hosts. TRV may be seed-borne in some crops. Inspect ornamentals and other hosts for TRV symptoms before purchasing. An incomplete list of susceptible hosts for TRV is listed below.
Table 1. Some susceptible hosts of TRV
Manage inoculum levels on your farm. Avoid spreading TRV and stubby-root nematodes from infested fields to clean fields.
- Monitor nematode populations in your fields by testing soil cores. Testing for stubby root nematodes helps you to make informed decisions about your fields. For more information see Diagnostic Testing.
- Practice strict on-farm sanitation protocols. Avoid moving contaminated soil, plant debris or manure to clean fields.
– Clean and sanitize all machinery and vehicles that have come into contact with infested soils or scabby tubers on your farm. Don’t forget to include equipment belonging to temporary help, contractors and anyone else entering the infested field. Follow the same procedures when borrowing or leasing used equipment.
– Do not return culls or potato debris to the field, destroy this material instead.
– Knives and other tools used for pruning or cutting tuber pieces must be contaminated often.
– Contain water and soil run off/waste generated from washing tubers to avoid contaminating other fields. Do not irrigate clean fields with water that contains runoff from infested fields.
– Do not reuse bags or containers that have been used for potato transport unless they are clean and free of soil.
– Restrict movement of soil from infested fields with hedgerows or sod barriers between fields. Do not use headlands, farm or public roads as turning areas.
– For more information please see Cleaning and Disinfecting Potato Equipment and Storage Facilities. - Avoid and destroy alternative hosts. If you need to use an infested field for other crops, do not grow or rotate with another host crop, such as sugar beet and tobacco, and bulb-producing ornamentals such as gladiolus, daffodil, hyacinth, and tulip. Destroy weed hosts, nightshade is especially dangerous as it is a good host for both the nematode and the virus.
- Manage nematodes with chemicals as part of an integrated management plan. Oxamyl (Vydate™) applied at planting and chemigated post-emergence applications can provide good control of stubby root nematodes and suppress TRV infection if applied at the appropriate intervals during the growing season. Applications of fluopyram (Velum Prime ™) followed by post-emergence applications of spirotetramat (Movento ™) have been demonstrated to provide suppression of stubby root nematodes. Fall fumigation prior to planting with 1,3 dichloropropene (Telone™) can reduce stubby root nematode populations. Always check with your local university extension personnel before application for specifics on timing and chemical rates, and to ensure the pesticide recommendation is up-to-date.
Plant potatoes strategically to reduce risk and the spread of disease.
- DO NOT plant seed potatoes in infested fields. This will spread the disease to other farms and put future sales at risk.
- Avoid planting ware potatoes in infested fields, if possible. Use of infested fields will increase the likelihood of spreading the disease to clean fields. If you find a field highly infested with TRV and stubby root nematodes, do not plant potatoes and other hosts of TRV. If you absolutely need to grow crops in an infested field, implement strict on-farm sanitation protocols so that the disease organisms remain contained.
- DO NOT plant ware potatoes or any other crop in highly infested fields.
- Be aware that planting any crop in TRV infested fields will increase your risk of spreading the pathogen on your farm. If you must grow crops in infested fields, be sure to practice a strict on-farm sanitation protocol.
Use TRV-resistant cultivars strategically to reduce loss.
- Grow cultivars resistant to TRV in stubby root nematode infested fields. Resistant varieties include Castile, Merrimack, Millennium Russet, Red Pearl, Symfonia, and St. Johns. Nooksack and Lemhi Russet are slightly resistant to developing corky ringspot. Russet Burbank is extremely susceptible to the disease (Hudelson, Charkowski UW Extension Pub. 2010). Table 2 (below) provides additional data on resistance to TRV induced tuber necrosis from field testing in 2016 and 2017.
- As noted under #3 above, be aware that planting any crop in PMTV infested fields will increase your risk on spreading the pathogen on your farm. If you must grow crops in infested fields, be sure to practice a strict on-farm sanitation protocol.
Table 2. Potato cultivar sensitivity to TRV-induced tuber necrosis. Data is from trials in ND and WA over 2 years.
(Yellareddygari, Brown, Whitworth, Quick, Hamlin and Gudmestad. 2018. Plant Dis. in press)
Ratings:
- Insensitive (overall incidence <5%)
- Moderately insensitive (overall incidence >5% to 10%)
- Moderately sensitive (overall incidence >10% to 15%)
- Sensitive (overall incidence >15%)
- ……Not tested/planted
