Search

Palisade Russet is a medium-late maturing, lightly russeted potato cultivar notable for its resistance to late blight (Phytophthora infestans) infection of foliage and tuber. Palisade Russet is suitable for processing with low tuber glucose concentrations observed following long-term storage at a temperature as low as 5.6°C with consistently acceptable fry color scores (USDA value ≤2.0) following storage at temperatures of 5.6 to 8.9°C. Reducing sugars are also maintained uniformly throughout the tuber, resulting in a low incidence of sugar ends in French fries relative to standard processing cultivars such as Russet Burbank and Ranger Russet. Palisade Russet has shown high specific gravities in western production regions of the U.S. which may limit its acceptance by the western processing industry. However, in potato production regions with inherently low specific gravities, Palisade Russet could have potential as a processing cultivar. In full-season trials conducted in Idaho, Oregon, and Washington over a 5 year period, the average total yield of Palisade Russet across all three states was very similar to yields observed for Ranger Russet and Russet Burbank. However, the U.S. No. 1 yield of Palisade Russet was 3% and 31% higher relative to Ranger Russet and Russet Burbank, respectively. In addition to late blight, Palisade Russet is also resistant to Verticillium wilt, black dot, and pink rot, and has a moderate level of resistance to net necrosis, PVY, and early blight of both the foliage and tuber. The disease resistances of Palisade Russet make it a good candidate for organic production, or for use by growers seeking reduced pesticide inputs. Palisade Russet displays a low incidence of second growth and growth cracks, especially relative to Russet Burbank, and is intermediate between Ranger Russet and Russet Burbank for incidence of hollow heart/brown center. Blackspot bruise expression for Palisade Russet is less pronounced than for either Ranger Russet or Russet Burbank, however it is slightly more susceptible to shatter bruise. Palisade Russet was released in 2011 by the USDA-ARS and the Agricultural Experiment Stations of Idaho, Oregon, and Washington, and is a product of the Pacific Northwest Potato Variety (Tri-State) Development Program.

Clearwater Russet is a medium-late maturing, russet-skinned, potato cultivar suitable for processing or fresh pack. It is notable for having a low incidence of external defects that contributes to its high U.S. No 1 yield relative to the dual-purpose industry standard, Russet Burbank. Clearwater Russet also maintains low glucose concentrations in its tubers during long-term storage making it an exceptional processing variety. With its low incidence of sugar ends and cold-induced sweetening resistance, Clearwater Russet can be stored at a temperature of 7.2°C for up to 250 days without the need for reconditioning; fry color from this storage regime is consistently ≤1.0 (USDA Fry Color Scale). This cultivar is also notable for its high tuber protein content, which was 33% greater than that of Russet Burbank. In full-season trials conducted over a 3-year period in California, Colorado, Idaho, Oregon, and Washington, Clearwater Russet had total yields slightly lower than Ranger Russet and Russet Burbank, but averaged 1% and 33% higher U.S. No. 1 yields, respectively, across all states. Average specific gravity of Clearwater Russet is comparable to Ranger Russet and significantly higher than Russet Burbank. Clearwater Russet is resistant to potato virus X (PVX) and tuber late blight and is moderately resistant to Verticillium wilt, common scab, and the common strain of potato virus Y (PVYO). Symptoms of infection with two necrotic strains of PVY were not observed in tubers of Clearwater Russet or Russet Burbank, but were observed in Ranger Russet. Blackspot bruise reaction for Clearwater Russet is less pronounced than for either Ranger Russet or Russet Burbank. The incidence of hollow heart in Clearwater Russet is intermediate between Ranger Russet and Russet Burbank. Internal brown spot has been noted as a problem for Clearwater Russet in the Columbia Basin of Oregon, but has not been observed as problematic in other growing regions. Clearwater Russet was released in 2008 by the USDA-ARS and the Agricultural Experiment Stations of Idaho, Oregon, and Washington, and is a product of the Pacific Northwest Potato Variety (Tri-State) Development Program.

Yukon Gem is a yellow-fleshed, medium to early-maturing cultivar suitable for fresh-pack or processing with a high level of resistance to potato virus Y O , and moderate foliar and tuber resistance to late blight. Multiple trials demonstrated a higher yield potential than Yukon Gold (yellow-fleshed industry standard). Yukon Gem produces uniform attractive tubers with light yellow skin and splashes of pink around the eyes; with flesh color similar to Yukon Gold. Yukon Gem was obtained from the intercrossing of Brodick and Yukon Gold at North Dakota State University (NDSU). An NDSU seedling tuber was sent and selected at Aberdeen, ID in 1995 and designated NDA5507-3YF. It advanced through the Aberdeen potato breeding program and regional trials in the western and northwestern U.S. Yukon Gem was released in 2006 by the USDA-ARS and the Agricultural Experiment Stations of Idaho, Oregon, and Washington, and is a product of the Northwest Potato Variety (Tri-State) Development Program.

Classic Russet is a medium maturing potato cultivar with rapid tuber bulking making it suitable for early harvest, as well as full-season production. Classic Russet is notable for its attractive tubers with medium russet skin and excellent culinary characteristics. It resulted from a 1995 cross between Blazer Russet and Summit Russet and was released in 2009 by the USDA-ARS and the Agricultural Experiment Stations of Idaho, Oregon and Washington and is a product of the Northwest Potato Variety (Tri-State) Development Program. Classic Russet also shows potential as an early season processing cultivar, with fry color comparable to Russet Burbank and Ranger Russet. Classic Russet total yields were comparable to Russet Norkotah and Ranger Russet in early harvest trials and comparable to Ranger Russet and Russet Burbank in full season trials. When averaged across sites in early harvest or full season trials, U.S. No. 1 yields of Classic Russet were generally greater than those of Russet Norkotah, Ranger Russet, and Russet Burbank. Protein content for Classic Russet is relatively high, averaging 22% higher than Ranger Russet, 32% higher than Russet Burbank and 24% higher than Russet Norkotah. Specific gravity of Classic Russet in early harvest trials was comparable to Russet Norkotah but lower than Ranger Russet and was similar to Russet Burbank in full season trials. The incidence of hollow heart in Classic Russet is low, similar to that of Ranger Russet. It is less susceptible to blackspot bruise than Russet Burbank, Ranger Russet and Russet Norkotah but shatter bruise can be a concern if not matured properly prior to harvest. Classic Russet is moderately resistant to common scab and dry rot and is moderately susceptible to foliar and tuber infections of early blight and symptoms of corky ringspot. It is susceptible to Verticillium wilt, soft rot, foliar and tuber late blight, PLRV and PLRV net necrosis, and the common strain of potato virus Y (PVY°).

Highland Russet is a late-season potato variety with light russet skin notable for its high yield of uniform U.S. No. 1 tubers, and good processing and culinary qualities. It resulted from a 1990 cross between Ranger Russet and Russet Legend and has been evaluated for over 15 years in public and industry trials throughout the western U.S. Highland Russet was released in 2006 by the USDA-ARS and the Agricultural Experiment Stations of Idaho, Oregon and Washington and is a product of the Northwest Potato Variety (Tri-State) Development Program. It is suitable for processing into French fries and other frozen potato products and due to its large blocky shape, recovers a high proportion of fries per unit weight of tubers. Fry color and processing ratings for Highland Russet were similar to Ranger Russet and Russet Burbank but fry color uniformity was higher than either of the standard varieties. In full-season trials conducted over a three-year period in the states of Idaho, Oregon, Washington, Colorado, and California; Highland Russet averaged 7% and 9% higher total yields and 21% and 52% higher U.S. No. 1 yields than Ranger Russet and Russet Burbank, respectively. It has moderately high specific gravity, with values similar to Ranger Russet and higher than Russet Burbank. Highland Russet is moderately resistant to Verticillium wilt and powdery scab root galling, as well as to tuber infections of late blight. It is also moderately resistant to common strains of potato virus Y (PVYO) but is susceptible to PVYNTN. It is moderately susceptible to pink rot, common scab, powdery scab of the tuber and early blight of the tuber, as well as to Pectobacterium soft rot and Fusarium dry rot. Highland Russet is susceptible to foliar late blight, PLRV infection, Root-knot nematode and corky ringspot but is moderately resistant to PLRV net necrosis. The incidence of hollow heart in Highland Russet is low, similar to that of Ranger Russet and lower than Russet Burbank, Blackspot bruise reaction of Highland Russet is similar to Russet Burbank but it is less susceptible to shatter bruise.

Premier Russet is a russet-skinned, high yielding potato cultivar suitable for processing or fresh-pack. Premier Russet is notable for its resistance to the accumulation of reducing sugars in its tubers. This characteristic allows tubers of Premier Russet to be stored at temperatures as low as 5.6°C for 250 days without the need for reconditioning prior to processing. The low temperature sweetening resistance of Premier Russet allows for its storage at colder temperatures which contributes to prolonged tuber dormancy and quality, and to a reduction in the incidence and severity of storage diseases associated with the higher storage temperatures typically used for industry-standard cultivars such as Russet Burbank and Ranger Russet. Premier Russet was released in 2006 by the USDA-ARS and the Agricultural Experiment Stations of Idaho, Oregon, and Washington, and is a product of the Northwest Potato Variety (Tri-State) Development Program. In full-season trials conducted over a 3-year period in the states of Idaho, Oregon, Washington, Colorado, California, New Mexico, and Texas, Premier Russet averaged 5% and 4% higher yields than Ranger Russet and Russet Burbank, respectively, and had a higher percentage of US No. 1 yield than either cultivar. Specific gravity of Premier Russet is consistently greater than that of Ranger Russet or Russet Burbank. Premier Russet is resistant to common and powdery scab, very resistant to the common strain of potato virus Y (PVYO), and moderately resistant to Verticillium wilt, early blight of the foliage and tuber, Pectobacterium (Erwinia) soft rot, and to galling of roots by powdery scab. Blackspot bruise reaction for Premier Russet is similar to that of Ranger Russet. The incidence of hollow heart in Premier Russet is higher than that of Ranger Russet or Russet Burbank. Cultural recommendations to manage hollow heart in Premier Russet are provided.

‘Blazer Russet’ is an early to mid-season cultivar notable for its high U.S. No. 1 yield of medium-russeted tubers and its good processing and culinary qualities. It was derived from the cross A7816-14 x ‘NorKing Russet’ and was released in 2005 by the USDA-ARS and the Agricultural Experiment Stations of Idaho, Oregon and Washington. Blazer Russet is very suitable for processing into French fries and other frozen potato products directly from the field or from extended storage, with higher merit scores than ‘Russet Burbank’ and ‘Ranger Russet’ in processing and post-harvest evaluations. Blazer Russet also has high merit for use in the fresh market, with sensory evaluations comparable to those of Russet Burbank. Total yields for Blazer Russet at five early harvest trial locations in the western United States were 12% greater than either ‘Russet Norkotah’ or ‘Shepody’, while U.S. No. 1 yields were 12% greater than Russet Norkotah and 35% greater than Shepody. Specific gravities of Blazer Russet tubers were comparable to tubers of Shepody, and higher than those of Russet Norkotah in early harvest trials. In full-season trials in the western United States, total yields for Blazer Rus set were slightly lower than Ranger Russet and slightly higher than Russet Burbank, but U.S. No. 1 yields were 8% greater than Ranger Russet and 38% greater than Russet Burbank. In these full-season trials, tuber specific gravity of Blazer Russet was similar to Russet Burbank, but lower than Ranger Russet. Blazer Russet is resistant to sugar ends, tuber malformations and most internal and external defects, the exception being its moderate susceptibility to hollow heart. Blazer Russet is resistant to common scab, tuber powdery scab and PVX, and has moderate resistance to blackspot bruise and tuber late blight infections. It is moderately susceptible to powdery scab root galling, PVY0, early blight infection of the tuber, Erwinia soft rot and Fusarium dry rot. Blazer Russet is susceptible to Verticillium wilt, pink rot, PLRV net necrosis, corky ringspot, and foliar early blight and late blight.

Western Russet, designated experimentally as A7961-1, and resulting from the cross A68113-4 x Bel-Rus, was released in 2004 by the USDA/ARS and the agricultural experiment stations of Idaho, Oregon, and Washington. The foliage of Western Russet is spreading, with medium-sized olive-green leaves and abundant white flowers. The tubers are tan, with medium russet skin, oblong shape, a slightly prominent eyebrow, white flesh, and distinctly visible pith. Western Russet was compared with Russet Burbank in trials across the Pacific Northwest for yield, quality, and disease response. In general, Western Russet produced lower total yields than Russet Burbank, but on average and depending on location, similar U.S. No. 1 yields. When observed for defect problems, Western Russet exhibited resistance to second growth, growth cracks, shatter bruise, stem-end discoloration, and heat necrosis, moderate resistance to hollow heart, and moderate susceptibility to blackspot bruise. In product quality tests, Western Russet was rated similar to Russet Burbank for french fry and dehydrated potato flake quality and slightly inferior for baked potato quality. In replicated evaluations, Western Russet was found to have good field resistance to common scab and PVYo, and moderate resistance to verticillium wilt and tuber net necrosis caused by PLRV. It demonstrated susceptibility to late blight, foliar PLRV, dry rot, soft rot, and tuber early blight. Biochemical analysis of Western Russet tubers showed markedly higher vitamin C content than those of Russet Burbank. Tuber glycoalkaloid concentration in tubers produced in a 1988 trial was 1.0 mg 100 g−1.

GemStar Russet, derived from the cross Gem Russet x A8341-5, was released in 2004 by the USDA/ARS and the agricultural experiment stations of Idaho, Oregon, and Washington. The foliage of GemStar Russet is dark yellowish-green, spreading, with large leaves and abundant white flowers. The tubers are brown, medium to heavily russeted, oblong, with a slightly prominent eyebrow, white flesh, and indistinct pith. GemStar Russet was compared with Russet Burbank and Russet Norkotah in trials across the Pacific Northwest for yield, quality, and disease response. Except for locations in southern Idaho, in general, GemStar Russet produced slightly lower total yield than Russet Burbank, but much higher U.S. No. 1 yield. When compared with Russet Norkotah, GemStar Russet produced similar total and U.S. No. 1 yields in early harvest trials but higher total and U.S. No. 1 yields in late-harvest trials. When observed for defect problems, GemStar Russet exhibited resistance to second growth, growth cracks, and stemend discoloration, moderate resistance to blackspot and shatter bruising, but a high level of susceptibility to hollow heart. In product quality tests, GemStar Russet was rated superior to Russet Burbank for french fry quality and comparable for baked potato quality. GemStar Russet was found to be immune to PVX, resistant to common scab and powdery scab, moderately resistant to Verticillium wilt, tuber net necrosis caused by PLRV, and corky ringspot. It demonstrated susceptibility to late blight, PLRV, dry rot, soft rot, and ringrot and extreme susceptibility to PVYo. Biochemical analysis of GemStar Russet tubers showed them to be higher in protein and much higher in vitamin C than those of Russet Burbank or Russet Norkotah. Three-year average for tuber glycoalkaloid concentration was 1.5 mg 100 g−1.

Gem Russet, a new medium maturing, long russet potato variety, was released in 2000 by the USDA/ARS and the experiment stations of Idaho, Oregon, and Washington. It is suited for use in the fresh, frozen-fried processing, and dehydration markets. Total tuber yield of Gem Russet is similar to that of Russet Burbank when grown in eastern Idaho, but lower when grown in the long-season areas of western Idaho and the Columbia Basin of Oregon and Washington. U.S. No. 1 yield is consistently higher that that of Russet Burbank. Tubers of Gem Russet have good processing and baked quality. Gem Russet is resistant to most external and internal physiological defects, including second growth, growth cracks, shatter bruise, and hollow heart. It is moderately susceptible to blackspot bruise. Gem Russet shows extreme resistance to potato virus X, resistance to common scab, and moderate resistance to early dying. Biochemical analysis of Gem Russet tubers has shown higher solids, lower reducing sugar and glycoalkaloid content, and higher concentration of protein and vitamin C when compared with tubers of Russet Burbank.

Klamath Russet, a late-maturing cultivar for fresh market use, was jointly released by the Agricultural Experiment Stations of Oregon, Idaho, and Washington and the U.S. Department of Agriculture in 2000. Klamath Russet was tested in irrigated trials in Oregon from 1990 to 1999 and in Western Regional Trials from 1994 to 1996. Klamath Russet yields of U.S. #ls have exceeded those for Russet Burbank and Russet Norkotah by more than 30%, averaged across all trials. Klamath Russet is moderately resistant to Verticillium wilt and highly resistant to common scab. Specific gravity for Klamath Russet has averaged 1.076 across all trials compared with 1.070 and 1.081 for Russet Norkotah and Russet Burbank, respectively. Klamath Russet is not considered suitable for french fry production because of high sugar and low starch contents.

Century Russet, a high-yielding, late-maturing variety suitable for fresh tablestock use, was jointly released in 1995 by Agricultural Experiment Stations in Oregon, Idaho, Washington, Colorado, California, and Texas and the USDA Agricultural Research Service. Extremely high yields have been observed for Century Russet in variety trials conducted in Oregon and throughout the western United States under a wide range of soil and climatic conditions. Century Russet produced 40 percent higher marketable yields than Russet Burbank and 67 percent higher marketable yields than Russet Norkotah in 11 regional trials conducted over a three-year period in sevenwestern states. Uniform tuber shape, high yields of count carton sizes, and attractive tuber appearance make Century Russet well suited for the fresh market industry. It is not recommended for chipping or processing into frozen products because of low solids and dark fry color. Century Russet is highly resistant toVerticillium wilt and consistently develops less hollow heart, brown center, and other internal defects than Russet Burbank. It requires more time between vine kill and harvest than Russet Burbank for adequate tuber maturity and skin set. Bruised Century Russet tubers are susceptible to early blight andFusarium infection.

Umatilla Russet, a moderately late maturing variety especially suitable for frozen French fry processing but also acceptable for tablestock use (boiling, and baking), was jointly released by the Agricultural Experiment Stations of Oregon, Idaho, and Washington and the U.S. Department of Agriculture in 1998. Umatilla Russet was evaluated in irrigated trials in Oregon from 1988 to 1997, and in western regional trials from 1989 to 1991. Total yields were similar to those of Russet Burbank, but Umatilla Russet produced higher marketable yields. In three years of regional trials at up to 13 locations in seven western states, Umatilla Russet averaged 40.5 Mg/ha compared with 32.4 Mg/ha for Russet. Burbank. Umatilla Russet fry color and specific gravity are consistently equal to or better than for Russet Burbank. Umatilla Russet is less susceptible toVerticillium wilt than Russet Norkotah, less susceptible to net necrosis than Russet Burbank, and resistant to PVX. It is susceptible to PLRV and expresses foliar symptoms of PVY more clearly than Russet Norkotah. Umatilla Russet is less susceptible to tuber infection and decay caused byPhytophthora infestans than Ranger Russet and Russet Norkotah. Umatilla Russet is less susceptible to hollow heart, brown center, growth cracks, and sugar ends, but more susceptible to blackspot and shatter bruise than Russet Burbank

Potato germplasm was assessed for resistance to corky ringspot disease (CRS) incited by transmission of tobacco rattle virus (TRV). TRV is transmitted by the stubby root nematode,Paratrichodorus allius, in the Pacific Northwest, and characterized by necrotic areas in the tuber. Four tests were conducted at two different problem fields in Umatilla, OR and Pasco, WA. The fields differed in the virulence of the virus isolates. Some clones and named varieties showed resistance only in the field with the relatively mild Umatilla isolate, while others remained symptomless at both sites. The host suitability of test potatoes to threeP. allius populations from the region was determined in greenhouse pot tests, and expressed as reproductive values [Rf = (final population of nematode at 55 days) / (initial population)]. TheR f values for the nematodes were not correlated with resistance ratings based on visual scoring of CRS symptoms in field grown potatoes. Thus, it appears that CRS resistance is based on reaction of potato genotypes to virus and not the vector. The availability of resistant clones inin vitro form is indicated.

A three-year study was conducted from 1991 through 1993 to evaluate the field performance of potato clones that had been selected for resistance to wilt symptom development and stem colonization byVerticillium dahliae. The total yield, size distribution, and specific-gravity of these highly resistant clones were compared with standard cultivars and two parent clones with high Verticillium resistance and high yield, A66107-51 and A68113-4. Two groups of Verticillium resistant germplasm were selected in 1991. One group was the highly resistant progeny from a cross between A66107-51 and A68113-4. The second group consisted of hybrids between wild species accessions with high Verticillium resistance and cultivated diploid and tetraploid germplasm.

Rishitin, lubimin, and solavetivone were the major sesquiterpenes found in 46 cultivars and breeding selections of potato (Solanum tuberosum L.). Concentrations of total sesquiterpenes were low or undetectable in untreated tuber slices, but ranged from 5 to 101 μg/g of fresh weight 4 days after treatment with the elicitor arachidonic acid. Seven genotypes produced significantly (P < 0.01) higher sesquiterpene concentrations than Russet Burbank (17 μg/g), a widely grown commercial cultivar. More than half of the genotypes tested were significantly (P < 0.01) different from Russet Burbank in sesquiterpene composition due to higher ratios of lubimin or solavetivone, both of which are reported to be biosynthetic precursors of rishitin. The highest ratios of solavetivone to total sesquiterpenes were strongly correlated with derivation from S. tuberosum ssp. andigena CPC 1673, which confers the H1 gene for resistance to the golden nematode (Globodera rostochiensis).

The reaction of 40 potato clones and six accessions ofSolanum spp. to wilt caused byVerticillium dahliae and to the acetone precipitate (AP) of the toxin produced by the pathogen in vitro was studied. There was a highly significant correlation between the wilt reaction of the clones in the glasshouse, the incidence and progress of wilt and severe wilt in the field, and the degree of colonization of stem apices byV. dahliae. Of the clones and accessions evaluated, NDA8694-3, Norgold Russet, BelRus, Superior, Russet Norkotah, Norland andS. demissum were the most susceptible, while A66107-51, A68113-4, Targhee, NDA843-3, Alpha, A7805-8, A7816-14, Russet Nugget,S. chacoense, S. sparsipilum, andS. tarijense were the most resistant to wilt. The reaction of genotypes to the AP ofV. dahliae toxin in an excised leaf bioassay was not correlated with their reaction to Verticillium wilt in the field or glasshouse.

Potato breeding selections A66107-51 and A68113-4 (Solanum tuberosum gptuberosum) are being released as germplasm that is highly resistant to Verticillium wilt (Verticillium dahliae Kleb.) These selections have been extensively evaluated for resistance to Verticillium as measured by symptom severity and degree of colonization byV. dahliae. They combine outstanding wilt resistance with good tuber maturity characteristics, high yield, and french fry processing tuber type. A66107-51 has long-oblong, russeted tubers, with high yield and variable processing quality. A68113-4 has long-oblong, partially russeted tubers with high yield and good processing quality. Both selections are fertile as female parents, and A66107-51 is occasionally pollen fertile. The Verticillium resistance of these two clones has been transmitted to progeny. These selections were developed by USDA-ARS in cooperation with the Idaho Agricultural Experiment Station. Seed is available from USDA-ARS, Aberdeen, Idaho.

The white potato became established in Europe and North America as an important crop during a 200 year period beginning in the mid 16th Century. The potato was first introduced to Europe from South America, either from the northern Andes as Solanum tuberosum gp. andigena (short day adapted), or from southern Chile as Solanum tuberosum gp. tuberosum (long day adapted) and the earliest descriptions are of what appear to be mixed genotypes (Salaman, 1949). From about 1550 to 1750, the potato was selected and adapted to the long day conditions of summer in the higher latitudes of Europe. By the late 1700s, distinct cultivars were recognized, and attempts were being made to improve the crop through cultivar selection. Problems with Potato leafroll virus genus Polerovirus, (PLRV) and Potato virus Y genus Potyvirus, (PVY) infection called “curl” induced the early breeders to select new clones with less symptoms and higher yields. Even though they did not really understand the cause of curl, they were quite adept at applied breeding, growing small populations from botanical seed, and then selecting the best seedlings. Cultivars, like White Kidney, Manly, and Lumper, to name a few from Great Britain and Ireland, came to be grown on a large scale, and there was less cultivar diversity than is present in more recent years in Europe (Salaman, 1949).

During 1980 and 1981 potato cultivars and breeding selections, including cultivated species and their hybrid derivatives, were evaluated for resistance to the green peach aphid (GPA),Myzus persicae (Sulzer), and to potato leafroll virus (PLRV). Criteria used were the number of aphids which colonized the clones in free choice field experiments and the number of plants derived from these experiments which showed symptoms of PLRV infection.

Foliar treatment of potato (Solanum tuberosum L.) with metribuzin at 0.57–1.0 lb/A caused a necrotic reaction in leaflets of plants infected with potato virus Y (PVY), but not in plants infected with potato virus X (PVX) or potato leafroll virus. Necrosis symptoms resulting from metribuzin-PVY interaction were distinct from symptoms of either PVY infection or of metribuzin injury. This reaction was similar in the Russet Burbank, Lemhi Russet, and Pioneer cultivars. Russet Burbank infected with PVY and PVX, alone or in combination, was treated with metribuzin to study herbicidevirus interaction effects on yield. Secondary PVY infection alone caused a 57% yield reduction, and when combined with PVX caused a 71% yield reduction. Although leaflet necrosis was induced by the metribuzin-PVY combination, there was no significant yield interaction. Results suggest that post-emergence application of metribuzin can be used as an aid for detecting and removing potato virus Y infected plants from potato seed fields