scholarly journals Pathogenicity and Aggressiveness of Three Alternaria spp. on Potato Foliage in the U.S. Northwest

Plant Disease ◽  
2016 ◽  
Vol 100 (4) ◽  
pp. 797-801 ◽  
Author(s):  
Lydia S. Tymon ◽  
Thomas F. Cummings ◽  
Dennis A. Johnson
Keyword(s):  
Alternaria Solani ◽  
Russet Burbank ◽  
Brown Spot ◽  
Columbia Basin ◽  
Russet Norkotah ◽  
Expansion Curve ◽  
Detached Leaves ◽  
Potato Foliage ◽  
Whole Plants ◽  
Umatilla Russet

Alternaria spp. were collected from potato foliage showing symptoms of early blight and brown spot in the Columbia Basin, WA and Bonners Ferry and Rupert, ID between 2009 and 2011. The aggressiveness of three Alternaria spp. on potato was quantified on nonwounded and wounded detached leaves of ‘Russet Norkotah’ potato; wounded detached leaves of ‘Alturas’, ‘Ranger Russet’, ‘Russet Burbank’, and ‘Umatilla Russet’; and whole plants of Russet Norkotah. Mean infection frequencies (MIF) and area under the lesion expansion curve (AULEC) were significantly greater for Alternaria solani (P = 0.0072 and 0.0002, respectively) than for A. arborescens or A. arbusti on nonwounded leaves. Wounding of tissue significantly increased MIF and AULEC for A. arbusti (P = 0.008 and 0.0047, respectively) and AULEC for A. arborescens (P = 0.01) relative to nonwounded tissue. AULEC did not differ significantly among the three Alternaria spp. when inoculated onto wounded foliage of whole plants (P = 0.34); the AULEC of whole plants was positively and significantly correlated with AULEC on detached leaves (P = 0.03). Umatilla Russet was the most susceptible and Russet Burbank was the least susceptible based on MIF and AULEC for all three pathogen species. Results indicate that A. solani was the more aggressive pathogen of potato in the Columbia Basin, because both A. arborescens and A. arbusti require wounds and A. arbusti lesions do not expand significantly in comparison with A. solani or A. arborescens following inoculation.

scholarly journals Aggressiveness of Isolates of Phytophthora infestans from the Columbia Basin of Washington and Oregon

1998 ◽  
Vol 88 (3) ◽  
pp. 190-197 ◽  
Author(s):  
Jeffrey S. Miller ◽  
Dennis A. Johnson ◽  
Philip B. Hamm
Keyword(s):  
Phytophthora Infestans ◽  
Lesion Size ◽  
Columbia Basin ◽  
Potato Plants ◽  
Progress Curve ◽  
Expansion Curve ◽  
The Us ◽  
Sporulation Capacity ◽  
Detached Leaflet Assay ◽  
Whole Plants

The aggressiveness of 22 isolates of Phytophthora infestans collected from naturally infected potato plants in the Columbia Basin of Washington and Oregon was determined on detached potato leaflets at 18°C in an incubator. Selected isolates were evaluated on whole plants in a greenhouse. Aggressiveness was measured by using the area under the lesion expansion curve (AULEC), incubation period, latent period, sporulation capacity, and lesion size on detached leaflets and the area under the disease progress curve and sporulation capacity on whole plants. The detached-leaflet assay was useful in that a large number of isolates were tested, several components of aggressiveness were studied, and significant differences were found among isolates. Significant variation for components of aggressiveness was found within and among isolates classified according to genotype. Significant interactions among isolates and cultivars were found for some components of aggressiveness, so results were pooled according to cultivar. On average, US-8 and US-11 isolates had higher AULEC scores, indicating aggressiveness higher than that of US-7, US-6, and US-1 genotypes. One US-8 genotype isolate had a higher standardized sporulation capacity than isolates of the other genotypes. US-6 genotype isolates were the least aggressive group, as indicated by low AULEC, sporulation capacity, and lesion size values. The replacement of the US-1 genotype by the US-8 genotype in the Columbia Basin may be partially explained by the increased aggressiveness of US-8 isolates. Additionally, potato growers may need to shorten intervals between fungicide applications and begin applications earlier.

scholarly journals Diversity and Virulence of Alternaria spp. Causing Potato Early Blight and Brown Spot in Wisconsin

2019 ◽  
Vol 109 (3) ◽  
pp. 436-445 ◽  
Author(s):  
Shunping Ding ◽  
Kiana Meinholz ◽  
Kenneth Cleveland ◽  
Stephen A. Jordan ◽  
Amanda J. Gevens
Keyword(s):  
Early Blight ◽  
Elongation Factor ◽  
Alternaria Solani ◽  
Potato Production ◽  
Russet Burbank ◽  
Brown Spot ◽  
Breeding Line ◽  
Quinone Outside Inhibitor ◽  
Significant Difference ◽  
Promising Source

Early blight, caused by Alternaria solani, along with brown spot, caused by A. alternata, have the potential to reduce quality and yield in potato production globally. Prior to this study, the incidence, disease impact, and fungicide resistance attributes of A. alternata in Wisconsin were poorly understood. Potato pathogens were isolated from foliar lesions at three commercial locations in Wisconsin in 2012 and 2017 and were initially morphologically identified as A. solani (n = 33) and A. alternata (n = 40). Identifications were further corroborated with the phylogenetic analysis of the internal transcribed spacer (ITS), translation elongation factor 1 (TEF1), gapdh, Alt a 1, and OPA10-2. A multigene phylogeny of ITS, TEF1, gapdh, and Alt a 1 showed five genotypes of A. alternata and one single genotype of A. solani. We demonstrated that the A. alternata isolates were virulent on potato cultivars Russet Burbank (P < 0.013) and Atlantic (P < 0.0073), though they caused less disease than A. solani (P < 0.0001 and P < 0.0001, respectively). A. alternata caused little disease on the breeding line 24-24-12 (P = 0.9929), and A. solani caused fewer disease symptoms on 24-24-12 than on Russet Burbank (P < 0.0001) or Atlantic (P < 0.0001). Breeding line 24-24-12 may be a promising source of potential resistance for the two diseases. There was no significant difference in virulence of different A. alternata genotypes, and no significant difference in virulence or genotype clustering among isolates from the three locations. Isolates of A. alternata that induced chlorosis caused larger lesion areas than isolates that did not in Russet Burbank (P < 0.0001), Atlantic (P < 0.0001), and 24-24-12 (P = 0.0365). There was no significant difference in virulence between quinone outside inhibitor (QoI)-sensitive and QoI-resistant isolates of A. alternata. This study enhanced our understanding of potato early blight and brown spot in Wisconsin, and suggested that A. alternata in addition to A. solani should be carefully monitored and possibly uniquely managed in order to achieve overall disease control.

scholarly journals Fungicide Resistance of Two Species of Alternaria from Potato in the Columbia Basin of Washington

Plant Disease ◽  
2014 ◽  
Vol 98 (12) ◽  
pp. 1648-1653 ◽  
Author(s):  
Lydia Tymon ◽  
Dennis A. Johnson
Keyword(s):  
Spore Germination ◽  
Fungicide Resistance ◽  
Mycelial Growth ◽  
Alternaria Solani ◽  
Threshold Concentration ◽  
Brown Spot ◽  
Cellular Respiration ◽  
Columbia Basin ◽  
Growth Ratio ◽  
Fungal Populations

Fungicides are extensively used in the Columbia Basin of Washington in an effort to manage early blight and brown spot on potato caused by Alternaria solani and A. alternata, respectively. Azoxystrobin and boscalid interfere with cellular respiration, and fungicide resistance is expected to occur in fungal populations due to the narrow modes of action dictated by each fungicide. The objective of this research was to assess A. solani and A. alternata populations in the Columbia Basin of Washington for azoxystrobin and boscalid resistance by initially screening isolates at a threshold concentration using mycelial growth and spore germination. Fifty isolates of A. solani and 58 of A. alternata were randomly selected for screening from 671 isolates collected from potato in the Columbia Basin from 2009 to 2011. Screening at a threshold concentration was done to estimate the range of fungicide resistance within the populations of A. solani and A. alternata in the region. Resistance of five isolates that differed in sensitivity to azoxystrobin and boscalid were then assessed for mycelial growth and spore germination at three fungicide concentrations in order to determine where rates were no longer effective. A. solani mycelial growth ratios and percent spore germination on azoxystrobin-amended media did not change from 2010 to 2011. A slight decrease in resistance of mycelial growth to azoxystrobin was exhibited among A. alternata isolates collected between 2010 and 2011. No change in sensitivity to azoxystrobin was observed in mycelial growth ratios among A. alternata isolates collected between 2010 and 2011. Resistance to boscalid by A. solani increased as indicated by a significant increase in mean mycelial growth ratio from 2010 to 2011, whereas A. alternata showed no change. Spore germination of A. solani was less at 100 μg/ml than at 1 or 10 μg/ml azoxystrobin. Spore germination of A. alternata did not differ among 1, 10, or 100 μg/ml azoxystrobin. Spore germination of A. solani and A. alternata did not differ among 0.5, 5, or 50 μg/ml boscalid. Resistance to azoxystrobin and boscalid in A. solani and A. alternata populations was shown to be present in the Columbia Basin and will likely become widespread with continued used of site-specific fungicides.

Mechanisms of pathogenesis in Sclerotium bataticola on sunflowers. 1. Production and translocation of a necrosis-inducing toxin

1969 ◽  
Vol 47 (7) ◽  
pp. 1147-1151 ◽  
Author(s):  
Yu-Ho Chan ◽  
W. E. Sackston
Keyword(s):  
Activated Carbon ◽  
Root System ◽  
Vascular System ◽  
Early Symptom ◽  
Vascular Tissues ◽  
Detached Leaves ◽  
Necrotic Spots ◽  
Whole Plants ◽  
Necrotic Spotting

Necrotic spotting of leaves is an early symptom of attack by Sclerotium bataticola on sunflowers. Spots appear after invasion of vascular tissues by the pathogen, which does not spread appreciably from the point of inoculation.Inoculation of one stem of plants split apically to give twin stems on one root system resulted in necrotic spotting of leaves first on the inoculated, and later on the uninoculated stem. Introducing cell-free filtrates of cultures of S. bataticola into sunflower plants or detached leaves resulted in production of the same type of necrotic spots. Introduction of eosin dye, which is translocated in the vascular system, into whole plants and detached leaves produced patterns of coloration similar to the patterns of necrotic spotting. The necrosis may be attributed to a translocatable toxin produced by the fungus.It is indicated that the toxin is neither an enzyme nor a protein. It has not been eluted after adsorption by activated carbon.

Effect of Potato virus Y on Yield of Three Potato Cultivars Grown Under Different Nitrogen Levels

Plant Disease ◽  
2006 ◽  
Vol 90 (1) ◽  
pp. 73-76 ◽  
Author(s):  
Jonathan L. Whitworth ◽  
Phil Nolte ◽  
Chris McIntosh ◽  
Robert Davidson
Keyword(s):  
Potato Virus ◽  
Potato Virus Y ◽  
Total Yield ◽  
Russet Burbank ◽  
Yield Reduction ◽  
Symptom Expression ◽  
Russet Norkotah ◽  
Nitrogen Levels ◽  
Foliar Symptoms ◽  
Significant Yield

Previous studies have shown that Potato virus Y (PVY) reduces yield in many cultivars. Typical foliar symptoms can include veinal necrosis, leaf drop, and a mosaic pattern sometimes accompanied by leaf roughness. Infection by PVY in Russet Burbank produces identifiable PVY symptoms, whereas cv. Russet Norkotah expresses mild, almost latent symptoms. Yield also is influenced by nitrogen fertilizer levels. This research was conducted to determine whether increased nitrogen mitigates yield reduction caused by PVY. Russet Norkotah, CO80011-5, and Russet Burbank were used in replicated plots of non-PVY-infected and PVY-infected plants at three nitrogen levels in 1995 and 1996. There was a significant yield reduction between PVY-negative and PVY-positive plots in all cultivars, at most nitrogen levels. PVY yield reduction was similar (approximately 38%) in the mild symptom expression clones of Russet Norkotah and CO80011-5, whereas the yield reduction in Russet Burbank, which exhibits typical symptom expression, was 63.5%. We conclude that increased nitrogen can influence total yield, but does not significantly mitigate the yield reduction due to PVY infection.

Virulence of Soybean Aphid, Aphis glycines (Hemiptera: Aphididae) Clones on Detached Leaves and Whole Plants

2020 ◽  
Vol 92 (3) ◽  
pp. 497 ◽  
Author(s):  
Doris Lagos-Kutz ◽  
Michelle L. Pawlowski ◽  
Brian W. Diers ◽  
Swapna R. Purandare ◽  
Kelley J. Tilmon ◽  
...  
Keyword(s):  
Soybean Aphid ◽  
Aphis Glycines ◽  
Detached Leaves ◽  
Whole Plants

Hairy Nightshade (Solanum sarrachoides) Competition with Two Potato Varieties

Weed Science ◽  
2011 ◽  
Vol 59 (1) ◽  
pp. 37-42 ◽  
Author(s):  
Pamela J. S. Hutchinson ◽  
Brent R. Beutler ◽  
JaNan Farr
Keyword(s):  
Potato Plant ◽  
Plant Biomass ◽  
Dry Weight ◽  
Field Trials ◽  
Russet Burbank ◽  
Potato Varieties ◽  
Russet Norkotah ◽  
Hairy Nightshade ◽  
Growth Habits ◽  
Extension Center

Greenhouse and field trials were conducted at the Aberdeen Research and Extension Center to determine the effect of hairy nightshade competition on two potato varieties with different growth habits. Greenhouse replacement trials included treatments of three plants total in each pot with potato : hairy nightshade ratios of 3 : 0, 2 : 1, 1 : 2, or 0 : 3. Varieties tested were ‘Russet Burbank’ and ‘Russet Norkotah’. Greenhouse-grown hairy nightshade (cotyledon to one-leaf stage) were transplanted into pots earlier than or at the same time as potato plant emergence. As the number of Russet Burbank plants per pot decreased, potato plant biomass dry weight (average per plant) increased, regardless of hairy nightshade number or transplant time. When hairy nightshade were transplanted before Russet Norkotah emergence, potato plant biomass dry weight per plant was similar, regardless of potato : nightshade ratio. Field trials were conducted with Russet Burbank and Russet Norkotah in 2004 and 2005. At potato emergence, greenhouse-grown hairy nightshade plants (one- to two-leaf) were transplanted in between potato rows at densities of 0, 1, 2, or 3 plants m−1row, and solid-seeded at approximately 100 plants m−1row. Hairy nightshade biomass, stem and berry number, and seeds per berry were reduced by competition from Russet Burbank due to the amount and duration of shading, as compared with Russet Norkotah. Russet Burbank U.S. No. 1 and total tuber yields in plots with 1 hairy nightshade plant m−1row were similar to weed-free control yields, whereas yields in plots with 2, 3, or 100 m−1row were reduced in comparison. In contrast, Russet Norkotah yields were reduced when only 1 hairy nightshade plant m−1row was present. Overall, Russet Norkotah were less competitive with hairy nightshade than Russet Burbank in both the greenhouse replacement and field trials.

Factors influencing incidence of internal brown spot in Russet Burbank potatoes

1984 ◽  
Vol 61 (6) ◽  
pp. 335-343 ◽  
Author(s):  
W. M. Iritani ◽  
L. D. Weller ◽  
N. R. Knowles
Keyword(s):  
Russet Burbank ◽  
Brown Spot ◽  
Internal Brown Spot ◽  
Factors Influencing

scholarly journals Responses of Aphid Vectors of Potato leaf roll virus to Potato Varieties

Plant Disease ◽  
2017 ◽  
Vol 101 (10) ◽  
pp. 1812-1818 ◽  
Author(s):  
Shaonpius Mondal ◽  
Erik J. Wenninger ◽  
Pamela J.S. Hutchinson ◽  
Jonathan L. Whitworth ◽  
Deepak Shrestha ◽  
...  
Keyword(s):  
Leaf Roll ◽  
Russet Burbank ◽  
Potato Leaf Roll Virus ◽  
Macrosiphum Euphorbiae ◽  
Potato Leaf ◽  
Potato Varieties ◽  
Ranger Russet ◽  
Russet Norkotah ◽  
Aphid Density ◽  
Aphid Abundance

Potato leaf roll virus (PLRV) can reduce tuber yield and quality in potato. Green peach aphid (Myzus persicae [Sulzer]) and potato aphid (Macrosiphum euphorbiae [Thomas]) are the two most important potato-colonizing PLRV vectors in the Pacific Northwest. We compared My. persicae and Ma. euphorbiae densities and PLRV incidences among potato varieties in the field to clarify the relationships between aphid abundance and PLRV incidence in plants. Aphids were sampled weekly over three years in the potato varieties Russet Burbank, Ranger Russet, and Russet Norkotah in a replicated field trial. In all years, My. persicae was more abundant than Ma. euphorbiae, representing at least 97% of samples. My. persicae densities did not differ among potato varieties across years; very low numbers of Ma. euphorbiae precluded such statistical comparisons for this species. PLRV infection did not differ significantly among potato varieties, although the percent of PLRV-infected plants differed among years when all varieties were combined (46% in 2013, 29% in 2011, 13% in 2012). For Ranger Russet and Russet Norkotah, PLRV incidence was positively correlated with aphid abundance as well as proportion of PLRV-positive aphids. In Russet Burbank, only aphid abundance was positively correlated with PLRV infection. Our results suggest that the three most commonly grown potato varieties in our region do not differ in their susceptibility to PLRV infection, and that aphid density was a consistent indicator of the risk of infection by this virus across varieties. Both of these findings can be used to hone PLRV monitoring and modeling efforts.

Potato Variety Tolerance to Flumioxazin and Sulfentrazone

2005 ◽  
Vol 19 (3) ◽  
pp. 683-696 ◽  
Author(s):  
Pamela J. S. Hutchinson ◽  
Rick A. Boydston ◽  
Corey V. Ransom ◽  
Dennis J. Tonks ◽  
Brent R. Beutler
Keyword(s):  
Potato Variety ◽  
Field Studies ◽  
Russet Burbank ◽  
Ranger Russet ◽  
Russet Norkotah ◽  
Early Injury ◽  
Russet Burbank Tuber ◽  
Initial Injury ◽  
Growing Conditions ◽  
Significant Injury

Field studies were conducted at Aberdeen, ID; Ontario, OR; and Paterson, WA, to evaluate potato tolerance to flumioxazin and sulfentrazone. In ‘Russet Burbank’ tolerance trials conducted in 2000 at ID, OR, and WA, sulfentrazone applied preemergence (PRE) at rates ranging from 105 to 280 g ai/ha caused significant injury consisting of stunting, leaf discoloration-blackening, and/or leaf malformation-crinkling at 4 wk after treatment (WAT). By 12 WAT, injury was ≤5%. At 4 WAT, flumioxazin applied PRE at 105 and 140 g ai/ha resulted in injury, whereas 53 g ai/ha did not cause significant injury. At 12 WAT, no visual injury was present at the ID site, whereas flumioxazin at 140 g/ha was still causing injury in WA. Regardless of initial injury, Russet Burbank tuber yields at ID, OR, and WA were not reduced as a result of any flumioxazin or sulfentrazone treatment compared with the nontreated controls. In potato variety tolerance trials conducted at ID in 2000 and at WA in 2002 with Russet Burbank, ‘Ranger Russet’, ‘Russet Norkotah’, and ‘Shepody’ and at ID in 2002 with those varieties plus ‘Alturas’ and ‘Bannock Russet’, early season injury caused by flumioxazin or sulfentrazone applied PRE at rates as high as 210 g ai/ha or 280 g/ha, respectively, occurred, but variety tuber yields were not reduced compared with nontreated control yields. In contrast, at ID in 2001, early injury caused by flumioxazin or sulfentrazone applied PRE at 105 or 210 g/ha translated to tuber yield reductions of all six varieties tested compared with the nontreated controls. At WA in 2001, Ranger Russet tuber yields were reduced by PRE applications of flumioxazin at 53 to 140 g/ha or sulfentrazone at 105 to 280 g/ha, and Shepody total tuber yields were reduced by all rates of PRE-applied sulfentrazone. Russet Burbank and Russet Norkotah tuber yields were unaffected by either herbicide. Unusual heat stress occurring early in the 2001 growing season at both locations may have compounded the effects of herbicide injury and, consequently, tuber yields were reduced in 2001, whereas injury occurring in 2000 or 2002 during relatively normal growing conditions did not translate to yield reductions.

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