scholarly journals Effect of Powdery Scab Root Galls on Yield of Potato

Plant Disease ◽  
2015 ◽  
Vol 99 (10) ◽  
pp. 1396-1403 ◽  
Author(s):  
Dennis A. Johnson ◽  
Thomas F. Cummings
Keyword(s):  
Potato Production ◽  
Powdery Scab ◽  
Spongospora Subterranea ◽  
Columbia Basin ◽  
Regression Analyses ◽  
North Central ◽  
Disease Symptoms ◽  
South Central ◽  
Gall Index ◽  
Umatilla Russet

Powdery scab of potato, caused by Spongospora subterranea f. sp. subterranea, has increased in incidence since 1981 to become a major concern for potato production in the Columbia Basin of south-central Washington and north-central Oregon. Disease symptoms consist of pustules on the tuber surface and wart-like galls on roots, stolons, and tubers. In the current study, the effect of powdery scab root galls on potato yield was quantified by comparing yields of cultivars susceptible and resistant to root galling grown on soil naturally infested and noninfested with the powdery scab pathogen. Potato tuber yields for the three yield components of yield per plant, number of tubers, and weight of tubers were not negatively affected by powdery scab galls on roots of Umatilla Russet and Shepody, as indicated by yield ratios ≥1.0 in 3 of 4 years, and also by regression analyses in all 3 years. Regression lines with a nonsignificant slope or slopes that significantly increased with gall index also indicated that root galls did not negatively affect yield. Mean tuber weight increased as gall index increased for Umatilla Russet in 2 of 3 years. Consequently, control tactics directed solely at reducing powdery scab galls on roots are not justified economically under conditions encountered in the Columbia Basin of Washington and Oregon states. Effort has been made to develop resistant cultivars and search for soil applied chemicals to reduce root galls.

scholarly journals First Confirmed Report of Powdery Scab Caused by Spongospora subterranea f. sp. subterranea on Potato in Sri Lanka

Plant Disease ◽  
2011 ◽  
Vol 95 (8) ◽  
pp. 1033-1033 ◽  
Author(s):  
A. G. C. Babu ◽  
U. Merz
Keyword(s):  
United States ◽  
Sri Lanka ◽  
The Netherlands ◽  
Potato Production ◽  
The United States ◽  
Powdery Scab ◽  
Research Station ◽  
Spongospora Subterranea ◽  
Seed Certification ◽  
Plant Pathol

White, wart-like outgrowths on roots and stolons – root galls – and blisters and pustules on tubers (lesions) are characteristic symptoms of the potato powdery scab disease caused by Spongospora subterranea (Wallr.) f. sp. subterranea. In Sri Lanka, potato is a major cash crop primarily in two agroecological zones of higher altitude, Nuwara Eliya and Badulla. Approximately 50% of the seed is produced nationally and the other half is imported from the Netherlands, France, Germany, and recently the United States (mainly high quality seed). During the 2002–2003 cultivation season, galls and lesions were observed on certified seed lots of potato cvs. Dura, Desiree, Roko, Cykoda, and Delawae imported from the Netherlands and planted in fields at the Seed Certification Service, Site Eliya near Nuwara Eliya, SriLanka after first inspection. Since then, similar symptoms were also observed on tubers and roots of cv. Granola at seed potato production sites in 2006 at Diagama, in 2007 at Bopathalawa, and in 2007 through 2010 at Pedru. In 2009 and 2010, blister-like lesions on tubers and root galls were again observed on seed of cvs. Calwhite, Keuka Gold, Red la Soda, and Chieftain imported from the United States and planted at the Agricultural Research Station, Site Eliya. In February 2004, a bioassay was carried out using healthy tubers of cvs. Roko, Cykoda, Delawae, and Isna to evaluate the potential contamination of field soils. Clay pots filled with soil samples collected from the suspected contaminated fields were planted with seed of the above cultivars. The pots were arranged in a complete random design with three replicates per cultivar in a place isolated from any potato-production location. Seventy-five days after planting, all varieties were recorded with white root galls but no lesions on the tubers. With light microscopy, suspected root and tuber tissue was examined to confirm the presence of the characteristic sporosori of the soilborne pathogen S. subterranea (Wallr.) f. sp. subterranea with their unique sponge-like structure (1). Additionally, two root galls and three tuber lesions were prepared for diagnostics by ELISA using antiserum produced against S. subterranea (Wallr.) f. sp. subterranea (3) and reactions were positive. Furthermore, in a lab-based bioassay (2), sporosori obtained from a single root gall and a single tuber lesion were used to inoculate tomato bait plants, cv. Marmande. Eight days postinoculation, zoosporangia were observed microscopically in roots at frequencies of 10 of 12 and 11 of 12 plants for the root gall and the tuber lesion, respectively. To our knowledge, the results presented here are the first confirmed report of the presence of S. subterranea (Wallr.) f. sp. subterranea, the causal agent of potato powdery scab in Sri Lanka. Powdery scab currently occurs at several places in Sri Lanka. Therefore, more attention should be paid to this disease in the seed certification process and seed import regulations concerning powdery scab should be strictly enforced. References: (1) C. H. Lawrence and A. R. McKenzie. Powdery scab. Page 35 in: Compendium of Potato Diseases. The American Phytopathological Society, St, Paul, MN, 1981. (2) U. Merz et al. Eur. J. Plant Pathol. 110:71, 2004. (3) U. Merz et al. Eur. J. Plant Pathol. 111:171, 2005.

Powdery scab (Spongospora subterranea) of potatoes in Queensland: occurrence, cultivar susceptibility, time of infection, effect of soil pH, chemical control and temperature relations

1980 ◽  
Vol 20 (106) ◽  
pp. 625 ◽  
Author(s):  
IK Hughes
Keyword(s):  
Soil Ph ◽  
Disease Incidence ◽  
Potato Production ◽  
Powdery Scab ◽  
Tuber Initiation ◽  
Spongospora Subterranea ◽  
Experimental Conditions ◽  
Time Of Infection ◽  
Serious Disease ◽  
Cultivar Susceptibility

Powdery scab of potatoes caused by the fungus Spongospora subterranea (Wallr.) Lagerheim was first recorded in Queensland in 1963. The disease appeared following a change in agronomic practice to winter potato production, and caused serious damage to those crops. Crops grown in warm weather even when grown on ground contaminated with S. subterranea were not affected. Sequoia, the preferred cultivar for winter production in south-eastern Queensland, was found to be very susceptible and has been largely replaced by less susceptible cultivars Extom and Kurrel. The reactions of other cultivars were recorded. Studies of time of infection, and the correlation of changing soil pH with disease and temperature data indicated that infection occurred soon after tuber initiation. Reduction of soil pH reduced disease incidence. More disease was recorded on large than on small tubers. The chemical quintozene gave control under experimental conditions in the field. Powdery scab is now a less serious disease in Queensland than it was in the early 1970s.

scholarly journals Resistance to Root Galling Caused by the Powdery Scab Pathogen Spongospora subterranea in Potato

Plant Disease ◽  
2008 ◽  
Vol 92 (12) ◽  
pp. 1643-1649 ◽  
Author(s):  
Nadav Nitzan ◽  
Tom F. Cummings ◽  
Dennis A. Johnson ◽  
Jeff S. Miller ◽  
Dallas L. Batchelor ◽  
...  
Keyword(s):  
Solanum Tuberosum ◽  
Wild Species ◽  
Field Trials ◽  
Russet Burbank ◽  
The Other ◽  
Powdery Scab ◽  
Spongospora Subterranea ◽  
Solanum Bulbocastanum ◽  
Commercial Cultivars ◽  
Umatilla Russet

Potato (Solanum tuberosum) selections (clones and commercial cultivars) were examined for resistance to root galling, caused by the powdery scab pathogen Spongospora subterranea f. sp. subterranea in seven field trials conducted between 2003 and 2007 in the states of Washington and Idaho. Four industry reference cultivars—Shepody, Russet Burbank, Russet Ranger, and Umatilla Russet—were used as susceptible standards. Every year, selections less susceptible than the standards were considered resistant and progressed to the next season. Selections that did not demonstrate resistance in at least two consecutive trials were discarded. Eight potato selections were more resistant to root galling than the susceptible standards in two or more trials: PA98NM38-1 was more resistant than the susceptible standards in 5 of 5 trials, PO94A009-10 in 4 of 5 trials, PA95B2-4 and PA98N5-2 in 3 of 5 trials, POR00HG5-1 in 2 of 5 trials, PO94A009-7 in 3 of 4 trials, PO94A012-2 in 2 of 3 trials, and Summit Russet in 2 of 2 trials. POR00HG5-1 has Solanum hougasii in its ancestry, while the other selections have the Mexican wild species Solanum bulbocastanum and the commercial cultivar Summit Russet appearing in their ancestry. Summit Russet is the most plausible source of resistance.

scholarly journals First Report of Potato Powdery Scab, Caused by Spongospora subterranea f. sp. subterranea, in North Dakota

Plant Disease ◽  
1997 ◽  
Vol 81 (6) ◽  
pp. 693-693 ◽  
Author(s):  
M. A. Draper ◽  
G. A. Secor ◽  
N. C. Gudmestad
Keyword(s):  
North Dakota ◽  
Seed Potato ◽  
Surface Defects ◽  
Solanum Tuberosum L ◽  
Disease Incidence ◽  
Potato Production ◽  
Powdery Scab ◽  
Irrigated Agriculture ◽  
Spongospora Subterranea ◽  
Diseased Tuber

Powdery scab is a serious disease of potatoes (Solanum tuberosum L.) that can cause extensive surface defects on susceptible potato cultivars. The pathogen, Spongospora subterranea (Wallr.) Lagerh. f. sp. subterranea J. A. Tomlinson, is an important concern in seed potato production because current seed certification standards in North Dakota have a zero tolerance for this pathogen. Powdery scab had not previously been identified in North Dakota. Until recently this disease was not thought to be present in U.S. commercial potato-producing areas. Powdery scab has now been shown to be more widely distributed than previously thought (1), having been identified in several locations in eastern and western North America. However, environmental conditions in North Dakota, including high soil pH, low rainfall, and high temperatures, are not considered favorable for powdery scab development. Diseased potatoes were found in a field from Griggs County, ND, in the fall of 1994 and characteristic cystosori were present in erumpent lesions on infected tubers. The field was an irrigated circle planted to three different cultivars. The cultivars Goldrush and Red Norland were symptomless, while cv. Red La-Soda was severely affected. Up to 30% of the tuber surfaces were diseased and disease incidence approached 25%. The infected crop was destroyed. Pathogenicity was confirmed by planting pieces of diseased tuber tissue adjacent to healthy seed pieces of Russet Burbank. Transmission of the obligate parasite occurred naturally by simulating conditions that were favorable for infection, acidic potting mix (Jiffy-Mix) maintained at a high water potential. Progeny plants were found to be infected on both tubers and roots after 60 days. Control plants that were not exposed to diseased tuber pieces were unaffected. North Dakota, a major seed-potato-producing state, ships seed to every other potato-producing area in the U.S. and much of Canada. Infected seed shipped to areas with a favorable environment for disease development may result in crops becoming diseased and unmarketable. The cooler temperatures and higher than normal rainfall during the 1992 to 1995 seasons may account for powdery scab development in North Dakota. Recent increases in irrigated agriculture and potato production in North Dakota could lead to the infestation of new areas, restricting the value of that land for potato production. Reference: (1) B. Christ et al. Am. Potato J. 65:583, 1988.

Relations of Sociodemographic Variables and Cognitive Ability: A Comparative Analysis of the Cognitive Scores of High School Seniors

1989 ◽  
Vol 69 (3-2) ◽  
pp. 1139-1157
Author(s):  
Hardeo Sahai
Keyword(s):  
High School ◽  
Socioeconomic Status ◽  
White Students ◽  
Mexican Americans ◽  
Minority Groups ◽  
High School Seniors ◽  
Or Education ◽  
Central Pacific ◽  
North Central ◽  
South Central

This paper compares subgroups using cognitive scores from a test battery administered to high school seniors in the base year survey in 1980. The procedures used to select the sample were designed to yield a data base that can be statistically projected to represent the national population of about 3,040,000 high school seniors. Comparisons were performed to examine differences in cognitive scores by age, sex, race/ethnicity, socioeconomic status, and census region. Boys scored higher than girls on mathematics and visualization tests, but lower on the picture-number and mosaic comparison tests. Mean scores of the two sexes on the vocabulary and reading tests differed by less than 0.1 SD. Asian/Pacific Islanders had higher means than white students and other minority groups on the mathematics, mosaic comparisons, and visualization test, but their scores did not differ significantly from those of white students on the other three tests. Means for Hispanics were lower than those for white students but higher than those for black students, except on reading. Mean scores of Cubans exceeded those of Mexican Americans, Puerto Ricans or other Hispanics. A positive correlation 0.40 obtained between test scores and the socioeconomic status or education attained by the examinees’ mothers. Students in New England had the highest means except on visualization for which the highest scores were in the West, followed in order by those in the Middle Atlantic, West North Central, East North Central, Pacific, Mountain, South Atlantic, East South Central, and West South Central regions.

scholarly journals Exposure of Domestic Cats to Three Zoonotic Bartonella Species in the United States

Pathogens ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 354
Author(s):  
Lynn M. Osikowicz ◽  
Kalanthe Horiuchi ◽  
Irina Goodrich ◽  
Edward B. Breitschwerdt ◽  
Bruno Chomel ◽  
...  
Keyword(s):  
New England ◽  
The United States ◽  
Severe Illness ◽  
Domestic Cats ◽  
Bartonella Species ◽  
Serum Samples ◽  
North Central ◽  
Middle Atlantic ◽  
South Central ◽  
Central Regions

Cat-associated Bartonella species, which include B. henselae, B. koehlerae, and B. clarridgeiae, can cause mild to severe illness in humans. In the present study, we evaluated 1362 serum samples obtained from domestic cats across the U.S. for seroreactivity against three species and two strain types of Bartonella associated with cats (B. henselae type 1, B. henselae type 2, B. koehlerae, and B. clarridgeiae) using an indirect immunofluorescent assay (IFA). Overall, the seroprevalence at the cutoff titer level of ≥1:64 was 23.1%. Seroreactivity was 11.1% and 3.7% at the titer level cutoff of ≥1:128 and at the cutoff of ≥1:256, respectively. The highest observation of seroreactivity occurred in the East South-Central, South Atlantic, West North-Central, and West South-Central regions. The lowest seroreactivity was detected in the East North-Central, Middle Atlantic, Mountain, New England, and Pacific regions. We observed reactivity against all four Bartonella spp. antigens in samples from eight out of the nine U.S. geographic regions.

scholarly journals Identifying and Characterizing Important Trembling Aspen Competitors with Juvenile Lodgepole Pine in Three South-Central British Columbia Ecosystems

2012 ◽  
Vol 2012 ◽  
pp. 1-12
Author(s):  
Teresa A. Newsome ◽  
Jean L. Heineman ◽  
Amanda F. Linnell Nemec
Keyword(s):  
British Columbia ◽  
Lodgepole Pine ◽  
Geographic Range ◽  
Regression Analyses ◽  
Relative Height ◽  
Trembling Aspen ◽  
Ecosystem Productivity ◽  
Height Ratio ◽  
Critical Height ◽  
South Central

Critical height ratios for predicting competition between trembling aspen and lodgepole pine were identified in six juvenile stands in three south-central British Columbia ecosystems. We used a series of regression analyses predicting pine stem diameter from the density of neighbouring aspen in successively shorter relative height classes to identify the aspen-pine height ratio that maximizedR2. Critical height ratios varied widely among sites when stands were 8–12 years old but, by age 14–19, had converged at 1.25–1.5. MaximumR2values at age 14–19 ranged from 13.4% to 69.8%, demonstrating that the importance of aspen competition varied widely across a relatively small geographic range. Logistic regression also indicated that the risk of poor pine vigour in the presence of aspen varied between sites. Generally, the degree of competition, risk to pine vigour, and size of individual aspen contributing to the models declined along a gradient of decreasing ecosystem productivity.

Effects of irrigation regimes on powdery scab disease and yield of potatoes

1986 ◽  
Vol 26 (6) ◽  
pp. 745 ◽  
Author(s):  
PA Taylor ◽  
SP Flett ◽  
RFde Boer ◽  
D Marshall
Keyword(s):  
Large Scale ◽  
Field Experiments ◽  
Field Trials ◽  
Powdery Scab ◽  
Infested Soil ◽  
Spongospora Subterranea ◽  
Potato Tubers ◽  
Potato Plants ◽  
Tuber Set ◽  
Large Scale Field

The period of susceptibility of potato tubers to powdery scab (Spongospora subterranea) was studied by inoculating potato plants with spores, or by watering plants in infested soil, at different stages of plant development in greenhouse conditions. Maximum susceptibility began about 1 week before the stage when 50% of stolons had swollen to at least 5-mm diameter (tuber set), and ended 3-4 weeks later. With holding irrigation water during this period reduced the severity of powdery scab by 65-75% in field experiments in 1981-82 and 1982-83, but had no apparent effect on disease severity in 3 out of 6 large-scale field trials during 1984-85.

Sign in / Sign up

Export Citation Format

Share Document