scholarly journals Outbreak of Phytophthora Foliar Blight and Fruit Rot in Processing Pumpkin Fields in Illinois

Plant Disease ◽  
2000 ◽  
Vol 84 (12) ◽  
pp. 1345-1345 ◽  
Author(s):  
M. Babadoost
Keyword(s):  
Phytophthora Capsici ◽  
The United States ◽  
Leaf Blight ◽  
Fruit Rot ◽  
Infected Leaf ◽  
American Phytopathological Society ◽  
Foliar Blight ◽  
Highly Correlated ◽  
June July ◽  
Central Illinois

Approximately 65% of the total commercial processing pumpkins (Cucurbita moschata Poir.) in the United States are produced in central Illinois. In 1999, Phytophthora capsici caused severe foliar blight and fruit rot in processing pumpkin fields in Illinois. Infection was widely observed in July when fruit weights were approximately 5 kg and continued until harvest in late August. Infection of the fruit generally started on the side contacting the soil. However, when an infected leaf came in contact with a fruit, fruit rot started at the site of contact. Many fruits that looked normal fell apart when they were turned for examination. Infected fruit were generally covered with white, cottony growth consisting of mycelium, sporangiophores, and sporangia. Leaf infection began as small chlorotic lesions, which enlarged and became necrotic. Leaf petioles also were infected and developed lesions that girdled petioles, causing the collapse and death of leaves. Vines also were infected and developed girdling lesions. The girdling lesions, which caused collapse and death of the vines, were observed on all parts of the vines. Affected vines collapsed and died. Roots and crowns of the plants with foliar blight and fruit rot exhibited little brownish discoloration or no symptoms. In most fields, the disease started in low-lying areas but spread rapidly throughout the field. The disease occurred in both irrigated and nonirrigated fields. In August, approximately 1 week before harvest, one nonirrigated and eight irrigated fields, a total of 267 ha, were surveyed to assess the incidence of disease. The incidence of disease was determined by examining vines, leaves, and fruit in 10 plots (36 m2 each) per field by walking a path on the longest diagonal of each field. In each plot, 10 plants were inspected, with one vine, 10 leaves on the vine, and one fruit of each plant (total of 10 vines, 100 leaves, and 10 fruits in each plot) were examined for infection. The incidence of vine blight, leaf blight, and fruit rot in the nonirrigated field was 30, 50, and 49%, respectively. The incidence of vine blight, leaf blight, and fruit rot in irrigated fields ranged from 4 to 48% (average 21%), 17 to 68% (average 40%), and 4 to 71% (average 32%), respectively. The incidence of vine blight, leaf blight, and fruit rot were highly correlated. Due to severe fruit rot, two of the irrigated fields were not harvested. In Illinois, processing pumpkins are planted in May and harvested in August. Recorded precipitation in the pumpkin growing area in Illinois in 1999, was 9 days (211 mm), 7 days (113 mm), 7 days (147 mm), and 7 days (91 mm) in May, June, July, and August, respectively. It is believed that the frequent and high rainfall during the growing season in the area resulted in the outbreak of Phytophthora foliar and fruit rot in processing pumpkins in Illinois in 1999. References: (1) D. C. Erwin and O. K. Ribeiro. 1996. Phytophthora Diseases Worldwide. The American Phytopathological Society, St. Paul, MN. (2) M. T. McGrath. 1998. Biological and Cultural Tests. The American Phytopathological Society, St. Paul, MN.

scholarly journals Evaluation of a Diverse, Worldwide Collection of Wild, Cultivated, and Landrace Pepper (Capsicum annuum) for Resistance to Phytophthora Fruit Rot, Genetic Diversity, and Population Structure

2015 ◽  
Vol 105 (1) ◽  
pp. 110-118 ◽  
Author(s):  
R. P. Naegele ◽  
A. J. Tomlinson ◽  
M. K. Hausbeck
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Phytophthora Capsici ◽  
The United States ◽  
Fruit Rot ◽  
Sources Of Resistance ◽  
Plant Introductions ◽  
Genetic Clusters ◽  
Commercial Breeding ◽  
Moderately Resistant

Pepper is the third most important solanaceous crop in the United States and fourth most important worldwide. To identify sources of resistance for commercial breeding, 170 pepper genotypes from five continents and 45 countries were evaluated for Phytophthora fruit rot resistance using two isolates of Phytophthora capsici. Genetic diversity and population structure were assessed on a subset of 157 genotypes using 23 polymorphic simple sequence repeats. Partial resistance and isolate-specific interactions were identified in the population at both 3 and 5 days postinoculation (dpi). Plant introductions (PIs) 640833 and 566811 were the most resistant lines evaluated at 5 dpi to isolates 12889 and OP97, with mean lesion areas less than Criollo de Morelos. Genetic diversity was moderate (0.44) in the population. The program STRUCTURE inferred four genetic clusters with moderate to very great differentiation among clusters. Most lines evaluated were susceptible or moderately susceptible at 5 dpi, and no lines evaluated were completely resistant to Phytophthora fruit rot. Significant population structure was detected when pepper varieties were grouped by predefined categories of disease resistance, continent, and country of origin. Moderately resistant or resistant PIs to both isolates of P. capsici at 5 dpi were in genetic clusters one and two.

scholarly journals Fungicide Rotation Programs for Managing Phytophthora Fruit Rot of Watermelon in Southeastern United States

2017 ◽  
Vol 18 (1) ◽  
pp. 28-34 ◽  
Author(s):  
Chandrasekar (Shaker) S. Kousik ◽  
Pingsheng Ji ◽  
Daniel S. Egel ◽  
Lina M. Quesada-Ocampo
Keyword(s):  
United States ◽  
South Carolina ◽  
Phytophthora Capsici ◽  
Southeastern United States ◽  
Heavy Rain ◽  
Integrated Approach ◽  
The United States ◽  
Fruit Rot ◽  
Management Options ◽  
Before And After

About 50% of the watermelons in the United States are produced in the southeastern states, where optimal conditions for development of Phytophthora fruit rot prevail. Phytophthora fruit rot significantly limits watermelon production by causing serious yield losses before and after fruit harvest. Efficacy of fungicide rotation programs and Melcast-scheduled sprays for managing Phytophthora fruit rot was determined by conducting experiments in Phytophthora capsici-infested fields at three locations in southeastern United States (North Carolina, South Carolina, and Georgia). The mini seedless cultivar Wonder and seeded cultivar Mickey Lee (pollenizer) were used. Five weekly applications of fungicides were made at all locations. Significant fruit rot (53 to 91%, mean 68%) was observed in the nontreated control plots in all three years (2013 to 2015) and across locations. All fungicide rotation programs significantly reduced Phytophthora fruit rot compared with nontreated controls. Overall, the rotation of Zampro alternated with Orondis was highly effective across three locations and two years. Rotations of Actigard followed by Ranman+Ridomil Gold, Presidio, V-10208, and Orondis, or rotation of Revus alternated with Presidio were similarly effective. Use of Melcast, a melon disease-forecasting tool, may occasionally enable savings of one spray application without significantly impacting control. Although many fungicides are available for use in rotations, under very heavy rain and pathogen pressure, the fungicides alone may not offer adequate protection; therefore, an integrated approach should be used with other management options including well-drained fields.

scholarly journals Characterizing Sources of Resistance to Phytophthora Blight of Pepper Caused by Phytophthora capsici in North Carolina

2019 ◽  
Vol 20 (2) ◽  
pp. 112-119
Author(s):  
Camilo H. Parada-Rojas ◽  
Lina M. Quesada-Ocampo
Keyword(s):  
North Carolina ◽  
Phytophthora Capsici ◽  
The United States ◽  
Field Trials ◽  
Fruit Rot ◽  
Phytophthora Blight ◽  
Sources Of Resistance ◽  
Crown Root ◽  
Different Levels ◽  
Important Disease

Phytophthora blight, caused by Phytophthora capsici, is an important disease of peppers in the United States and worldwide. P. capsici causes crown, root, and fruit rot as well as foliar lesions in peppers. Field trials were conducted in 2015 and 2016 to evaluate 32 commercial and experimental pepper cultivars against a mixed-isolate inoculum in North Carolina. Cultivars Martha-R and Meeting were classified as highly resistant to P. capsici, and Paladin was classified as resistant. Intermediate resistance to P. capsici in the field was observed with Fabuloso, Revolution, Vanguard, Archimedes, Aristotle, Ebano-R, and Declaration. Greenhouse experiments were conducted to determine the response of 48 pepper cultivars when inoculated individually with two isolates from North Carolina and an isolate from Michigan. Isolates exhibited different levels of virulence in pepper cultivars screened for resistance. Landraces CM334 and Fidel as well as the cultivars Martha-R, Meeting, and Intruder were categorized as highly resistant or resistant to the three isolates tested. Overall, highly resistant cultivars tended to respond similarly to field mix inoculations and greenhouse single isolate inoculations.

scholarly journals Advances in Research on Phytophthora capsici on Vegetable Crops in The United States

Plant Disease ◽  
2012 ◽  
Vol 96 (11) ◽  
pp. 1588-1600 ◽  
Author(s):  
Leah L. Granke ◽  
Lina Quesada-Ocampo ◽  
Kurt Lamour ◽  
Mary K. Hausbeck
Keyword(s):  
Host Range ◽  
Phytophthora Capsici ◽  
The United States ◽  
Fruit Rot ◽  
Economic Losses ◽  
Future Research ◽  
Vegetable Crops ◽  
Long Distance ◽  
Term Survival ◽  
Wide Range

Since L. H. Leonian's first description of Phytophthora capsici as a pathogen of chile pepper in 1922, we have made many advances in our understanding of this pathogen's biology, host range, dissemination, and management. P. capsici causes foliar blighting, damping-off, wilting, and root, stem, and fruit rot of susceptible hosts, and economic losses are experienced annually in vegetable crops including cucurbits and peppers. Symptoms of P. capsici infection may manifest as stunting, girdling, or cankers for some cultivars or crops that are less susceptible. P. capsici continues to be a constraint on production, and implementation of an aggressive integrated management scheme can still result in insufficient control when weather is favorable for disease. Management of diseases caused by P. capsici is currently limited by the long-term survival of the pathogen as oospores in the soil, a wide host range, long-distance movement of the pathogen in surface water used for irrigation, the presence of fungicide-resistant pathogen populations, and a lack of commercially acceptable resistant host varieties. P. capsici can infect a wide range of hosts under laboratory and greenhouse conditions including cultivated crops, ornamentals, and native plants belonging to diverse plant families. As our understanding of P. capsici continues to grow, future research should focus on developing novel and effective solutions to manage this pathogen and prevent economic losses due to the diseases it causes.

scholarly journals Screening of Cucurbita moschata Duchesne Germplasm for Crown Rot Resistance to Floridian Isolates of Phytophthora capsici Leonian

HortScience ◽  
2011 ◽  
Vol 46 (4) ◽  
pp. 536-540 ◽  
Author(s):  
Dario J. Chavez ◽  
Eileen A. Kabelka ◽  
José X. Chaparro
Keyword(s):  
Root Rot ◽  
Phytophthora Capsici ◽  
Crown Rot ◽  
Fruit Rot ◽  
Cucurbita Moschata ◽  
Breeding Lines ◽  
Foliar Blight ◽  
Disease Rating ◽  
Crown And Root Rot ◽  
Highly Virulent

Phytophthora capsici causes seedling death, crown and root rot, fruit rot, and foliar blight on squash and pumpkins (Cucurbita spp. L.). A total of 119 C. moschata accessions, from 39 geographic locations throughout the world, and a highly susceptible butternut squash cultivar, Butterbush, were inoculated with a suspension of three highly virulent P. capsici isolates from Florida to identify resistance to crown rot. Mean disease rating (DR) of the C. moschata collection ranged from 1.4 to 5 (0 to 5 scale with 0 resistant and 5 susceptible). Potential resistant and tolerant individuals were identified in the C. moschata collection. A set of 18 PIs from the original screen were rescreened for crown rot resistance. This rescreen produced similar results as the original screen (r = 0.55, P = 0.01). The accessions PI 176531, PI 458740, PI 442266, PI 442262, and PI 634693 were identified with lowest rates of crown infection with a mean DR less than 1.0 and/or individuals with DR = 0. Further selections from these accessions could be made to develop Cucurbita breeding lines and cultivars with resistance to crown rot caused by P. capsici.

scholarly journals Comparative Genomic Analysis Reveals Genetic Variation and Adaptive Evolution in the Pathogenicity-Related Genes of Phytophthora capsici

2021 ◽  
Vol 12 ◽  
Author(s):  
Joung-Ho Lee ◽  
Muhammad Irfan Siddique ◽  
Jin-Kyung Kwon ◽  
Byoung-Cheorl Kang
Keyword(s):  
Phytophthora Capsici ◽  
Genomic Analysis ◽  
Gene Families ◽  
Comparative Genomic Analysis ◽  
Fruit Rot ◽  
Comparative Genomic ◽  
Related Gene ◽  
Foliar Blight ◽  
Accelerated Evolution ◽  
Oomycete Pathogen

Phytophthora capsici is an oomycete pathogen responsible for damping off, root rot, fruit rot, and foliar blight in popular vegetable and legume crops. The existence of distinct aggressiveness levels and physiological races among the P. capsici population is a major constraint to developing resistant varieties of host crops. In the present study, we compared the genomes of three P. capsici isolates with different aggressiveness levels to reveal their genomic differences. We obtained genome sequences using short-read and long-read technologies, which yielded an average genome size of 76 Mbp comprising 514 contigs and 15,076 predicted genes. A comparative genomic analysis uncovered the signatures of accelerated evolution, gene family expansions in the pathogenicity-related genes among the three isolates. Resequencing two additional P. capsici isolates enabled the identification of average 1,023,437 SNPs, revealing the frequent accumulation of non-synonymous substitutions in pathogenicity-related gene families. Furthermore, pathogenicity-related gene families, cytoplasmic effectors and ATP binding cassette (ABC) transporters, showed expansion signals in the more aggressive isolates, with a greater number of non-synonymous SNPs. This genomic information explains the plasticity, difference in aggressiveness levels, and genome structural variation among the P. capsici isolates, providing insight into the genomic features related to the evolution and pathogenicity of this oomycete pathogen.

scholarly journals Identification of Novel Physiological Races of Phytophthora capsici Causing Foliar Blight Using the New Mexico Recombinant Inbred Pepper Lines Set as a Host Differential

2011 ◽  
Vol 136 (3) ◽  
pp. 205-210 ◽  
Author(s):  
Ariadna Monroy-Barbosa ◽  
Paul W. Bosland
Keyword(s):  
New Mexico ◽  
Recombinant Inbred ◽  
Recombinant Inbred Lines ◽  
Phytophthora Capsici ◽  
The United States ◽  
Inbred Lines ◽  
Physiological Races ◽  
Foliar Blight ◽  
Physiological Race ◽  
Geographical Locations

Phytophthora foliar blight caused by Phytophthora capsici is a serious limitation to pepper (Capsicum annuum) production worldwide. Knowledge of the physiological race composition of isolates causing phytophthora foliar blight is necessary for success in breeding for disease resistance. The New Mexico recombinant inbred lines (NMRILs) effectively differentiated isolates from different geographical locations (i.e., Turkey, The Netherlands, Argentina, and two states in the United States) into 12 physiological races of P. capsici causing phytophthora foliar blight. This research demonstrates the use of the NMRILs to identify P. capsici foliar blight races and the importance of identifying the physiological races occurring in specific regions where a C. annuum cultivar will be grown. Knowing the physiological race(s) in a region will provide valuable information to formulate breeding strategies to deploy durable foliar blight resistance.

scholarly journals First Report of Botrytis cinerea Causing Gray Mold of Pomegranate (Punica granatum) in Greece

Plant Disease ◽  
2009 ◽  
Vol 93 (12) ◽  
pp. 1346-1346 ◽  
Author(s):  
G. A. Bardas ◽  
G. D. Tzelepis ◽  
L. Lotos ◽  
G. S. Karaoglanidis
Keyword(s):  
Botrytis Cinerea ◽  
Morphological Characteristics ◽  
Punica Granatum ◽  
The United States ◽  
Gray Mold ◽  
Fruit Rot ◽  
American Phytopathological Society ◽  
First Report ◽  
Surface Sterilization ◽  
Food Agric

Pomegranate is rapidly increasing in production in Greece. During August of 2008 in the region of Larisa (central Greece), preharvest fruit rot was observed on pomegranate (cv. Kapmaditika) that caused losses estimated at 10%. Symptoms first appeared as small spots on the fruits that later increased in size and developed into expanded, dark brown lesions. Internally, tissues were soft and brown with gray mycelia and conidiophores observed. Affected fruits decayed completely during 2 months of storage (5 to 6°C), causing yield losses of up to 20%. To isolate the casual agent, conidia and conidiophores were scraped aseptically from the internal tissues, suspended in sterile water, and streaked onto the surface of potato dextrose agar (PDA). Single hyphal tips were transferred to PDA, and the isolated fungus was identified as Botrytis cinerea Pers.:Fr. on the basis of morphological characteristics (2). B. cinerea was consistently isolated from symptomatic tissues. Colonies of B. cinerea on PDA were at first colorless and became gray to brown with the development of lemon-shaped conidia (average 7.5 × 9 μm). Sclerotia were black and varied in size (1.4 to 4.5 × 1.5 to 2.7 mm) and shape (2). Pathogenicity of the isolated fungus was tested by wound inoculating five mature pomegranate fruits (cv. Kampaditika) after surface sterilization with 5% sodium hypochlorite. Plugs of the fungus (5 mm in diameter) obtained from the colony margins were transferred onto a 3- × 3-mm wound on the surface of sterilized fruit. Sterile PDA plugs were used to inoculate five control pomegranate fruits. Fruit were incubated at 22°C and 80% relative humidity in the dark. Extensive decay, similar to that observed on diseased fruits in the field, was observed on inoculated fruits 7 days after inoculation, whereas control fruits showed no decay. The pathogen was reisolated from internal rotten tissues of inoculated fruit, but not from the noninoculated control fruits. Fruit rot of pomegranate caused by B. cinerea has been reported previously in the United States (1) and China (3). However, to our knowledge, this is the first report of B. cinerea causing gray mold of pomegranate in Greece. References: (1) A. M. French. California Plant Disease Host Index. Calif. Dept. Food Agric., Sacramento, 1989. (2) W. B. Hewitt. Compendium of Grape Diseases. American Phytopathological Society, 1994. (3) Z. Zhang. Flora Fungorum Sinicorum 26:277, 2006.

scholarly journals First Report of Leaf Blight of Dianthus chinensis Caused by Rhizoctonia solani

Plant Disease ◽  
2000 ◽  
Vol 84 (12) ◽  
pp. 1344-1344
Author(s):  
G. E. Holcomb ◽  
D. E. Carling
Keyword(s):  
United States ◽  
Rhizoctonia Solani ◽  
Gulf Coast ◽  
The United States ◽  
Anastomosis Group ◽  
Early Spring ◽  
Leaf Blight ◽  
Infected Leaf ◽  
First Report ◽  
Bedding Plant

Dianthus chinensis (rainbow pink) is a popular seasonal bedding plant for the Gulf Coast of the United States and is primarily grown during the fall, winter, and early spring months. In August 1999, diseased plants were observed in a Baton Rouge, LA, propagation nursery with irregularly oval, tan leaf spots 3 to 10 mm in diameter. Heavily infected leaves became blighted and were killed, but plants survived and roots, crowns, and flowers were not affected. Infected leaf samples were surface-disinfected for 1 to 3 min in 70% ethyl alcohol, blotted dry, and sections were placed on 2% acidified water agar. A fungus that was identified as Rhizoctonia solani, and belonging to anastomosis group (AG)-1 IB, was consistently isolated from infected leaves. Inoculum was prepared by blending one 7-day-old plate culture, grown on acidified potato-dextrose agar, in 100 ml distilled deionized water. Pathogenicity tests were performed by dripping inoculum from a 10-ml pipette on leaf surfaces of healthy rainbow pink plants. Inoculated and noninoculated plants were held in a dew chamber at 26°C for 2 to 3 days and then removed to a greenhouse where temperatures ranged from 25 to 32°C. Inoculated plants developed water-soaked spots after 2 to 3 days that turned tan and became necrotic 5 to 10 days later. These symptoms were like those observed on the original diseased plants. R. solani was reisolated from inoculated plants, and noninoculated plants remained healthy. Although R. solani has been reported previously as a root and stem pathogen of D. chinensis (1), this is the first report of leaf blight disease caused by this fungus. Reference: (1) D. F. Farr et al. 1989. Fungi on Plants and Plant Products in the United States. American Phytopathological Society, St. Paul, MN.

scholarly journals Phytophthora Root Rot Resistance and Its Correlation with Fruit Rot Resistance in Capsicum annuum

HortScience ◽  
2020 ◽  
Vol 55 (12) ◽  
pp. 1931-1937
Author(s):  
Rachel P. Naegele ◽  
Mary K. Hausbeck
Keyword(s):  
Broad Spectrum ◽  
Root Rot ◽  
Partial Resistance ◽  
Phytophthora Capsici ◽  
Fruit Rot ◽  
Multiple Sources ◽  
Sources Of Resistance ◽  
Phytophthora Root Rot ◽  
Foliar Blight ◽  
Moderate Resistance

Phytophthora capsici causes root and fruit rot and foliar blight of pepper. Multiple sources of resistance to Phytophthora root rot have previously been identified, but most display only partial resistance. One source, CM334, has broad spectrum root rot resistance to multiple pathogen isolates but has only low to moderate fruit rot resistance. This study evaluated previously identified pepper lines for resistance to two P. capsici isolates, OP97 and 12889, and compared root rot resistance to fruit rot resistance and genetic structure. CM334 was confirmed as a broad spectrum resistance genotype, whereas all other sources of resistance evaluated were susceptible to infection by one or both isolates evaluated. Although not completely resistant, PI 566811 displayed moderate resistance to fruit and root rot to both P. capsici isolates. Fruit rot resistance had a significant but small to moderate positive correlation (r = 0.26–0.63) with root rot resistance depending on the isolate and length of exposure. Pepper accessions with resistance to Phytophthora root and fruit rot belonging to different genetic subpopulations were identified and could serve as candidates for partial-resistance loci to incorporate into pepper breeding programs.

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