scholarly journals Comparison of Five Fungicides on Development of Root, Crown, and Fruit Rot of Chile Pepper and Recovery of Phytophthora capsici from Soil

Plant Disease ◽  
2000 ◽  
Vol 84 (9) ◽  
pp. 1038-1043 ◽  
Author(s):  
M. E. Matheron ◽  
M. Porchas
Keyword(s):  
Phytophthora Capsici ◽  
Fruit Rot ◽  
Infested Soil ◽  
Phytophthora Blight ◽  
Lesion Development ◽  
Management Tools ◽  
Chile Pepper ◽  
Chemical Management ◽  
Relative Value ◽  
Survival And Growth

The activity of five fungicides, azoxystrobin, dimethomorph, fluazinam, fosetyl-Al, and metalaxyl (subsequently replaced with mefenoxam by the manufacturer), was compared for effects on the development of root, crown, and fruit rot of chile pepper and on recovery of Phytophthora capsici from naturally infested soil. When inoculated with zoospores, plants survived longer and shoot and root fresh weights were greater for plants drenched with metalaxyl at 10 μg/ml than for plants treated with the same rate of azoxystrobin or dimethomorph. At 100 μg/ml, the duration of plant survival was greater for dimethomorph and fluazinam than for azoxystrobin; however, shoot and root growth did not differ. In soil naturally infested with P. capsici, survival and growth of shoots and roots for plants treated with dimethomorph at 100 μg/ml were greater than for those treated with the same rate of azoxystrobin or fluazinam. The most effective compounds for inhibition of lesion development on stems and fruit were mefenoxam at 1,200 μg/ml and dimethomorph at 480 μg/ml. Recovery of P. capsici from soil treated with each of the five tested compounds was significantly less than that recorded for soil not receiving a fungicide. The potential and relative value of azoxystrobin, dimethomorph, fosetyl-Al, and fluazinam as chemical management tools for Phytophthora blight on chile pepper, in addition to metalaxyl (replaced with mefenoxam), has been demonstrated.

scholarly journals Evaluation of Winter Squash and Pumpkin Cultivars for Age-related Resistance to Phytophthora capsici Fruit Rot

HortScience ◽  
2016 ◽  
Vol 51 (10) ◽  
pp. 1251-1255 ◽  
Author(s):  
Charles S. Krasnow ◽  
Mary K. Hausbeck
Keyword(s):  
Cucurbita Pepo ◽  
Disease Incidence ◽  
Phytophthora Capsici ◽  
Genetic Resistance ◽  
Fruit Rot ◽  
Infested Soil ◽  
Cucurbita Moschata ◽  
Cucurbita Maxima ◽  
Age Related ◽  
Winter Squash

Phytophthora capsici annually threatens production of cucurbit and solanaceous crops. Long-lived oospores produced by the pathogen incite primary infection of susceptible plants when conditions are wet. Limiting the rot of winter squash and pumpkin (Cucurbita sp.) fruits is difficult due to the long maturation period when fruits are often in direct contact with infested soil. Genetic resistance to fruit rot is not widely available within Cucurbita sp.; however, age-related resistance (ARR) to P. capsici fruit rot develops in specific cultivars during maturation. The objective of this study was to evaluate the fruits of 12 cultivars of Cucurbita pepo, Cucurbita moschata, and Cucurbita maxima for ARR to P. capsici using a mycelial-plug inoculation method. All Cucurbita pepo and Cucurbita moschata cultivars displayed ARR; 7 days postpollination (dpp) fruits were susceptible, limited lesion development occurred on fruits 22 dpp, and lesions did not develop at 56 dpp. Disease developed on both Cucurbita maxima cultivars tested at 7, 14, 22, and 56 dpp. Firmness of fruit exocarps was measured with a manual penetrometer. Exocarp firmness of all cultivars increased during maturation; however, there was no correlation between firmness and disease incidence among cultivars at 22 dpp (R2 = −0.01, P = 0.85). When fruits of cultivars expressing ARR at 22 dpp were wounded before inoculation, fruit rot developed.

scholarly journals A Rapid Technique for Multiple-race Disease Screening of Phytophthora Foliar Blight on Single Capsicum annuum L. Plants

HortScience ◽  
2010 ◽  
Vol 45 (10) ◽  
pp. 1563-1566 ◽  
Author(s):  
Ariadna Monroy-Barbosa ◽  
Paul W. Bosland
Keyword(s):  
Capsicum Annuum ◽  
Root Rot ◽  
Recombinant Inbred Lines ◽  
Phytophthora Capsici ◽  
Pepper Plant ◽  
Phytophthora Blight ◽  
Chile Pepper ◽  
Physiological Races ◽  
Foliar Blight

Phytophthora blight, caused by the oomycete Phytophthora capsici Leon., is a major disease that threatens production and long-term viability of the chile pepper (Capsicum annuum L.) industry. For each phytophthora disease syndrome such as root rot, foliar blight, and stem blight separate and independent resistant systems have evolved in the host. In addition, several physiological races of the pathogen have been identified. A novel, effective, and accurate screening technique is described that allows for multiple races to be evaluated on a single plant of C. annuum. The P. capsici resistant line Criollo de Morelos-334, a susceptible cultivar, Camelot, and three New Mexico Recombinant Inbred Lines, -F, -I, -S, were used to evaluate the new technique for phytophthora foliar blight multiple-race screening. Using three P. capsici physiological races, no interaction among the physiological races was observed with this technique. This novel technique provided a rapid disease screen evaluating multiple physiological races for phytophthora foliar blight resistance in a single chile pepper plant and can assist plant breeders in selecting for disease-resistant plants.

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.

Effectiveness of 14 Fungicides for Suppressing Lesions Caused by Phytophthora capsici on Inoculated Stems of Chile Pepper Seedlings

2014 ◽  
Vol 15 (4) ◽  
pp. 166-171 ◽  
Author(s):  
Michael E. Matheron ◽  
Martin Porchas
Keyword(s):  
Environmental Conditions ◽  
Phytophthora Capsici ◽  
Field Trials ◽  
Application Site ◽  
Phytophthora Blight ◽  
Chile Pepper ◽  
Stem Lesion ◽  
Plant Foliage ◽  
Oomycete Pathogen ◽  
Lesion Growth

Phytophthora blight, caused by the oomycete pathogen Phytophthora capsici, is an economically important disease in bell and chile pepper. Fourteen different fungicides were evaluated with respect to inhibition of stem lesion growth on chile pepper seedlings inoculated with mycelium or with zoospores of P. capsici 1 or 3 weeks after treatment of plant foliage and stems or roots. Fungicides containing ametoctradin + dimethomorph and fluopicolide were the most effective among tested products in both experiments across eight trial parameters (inoculum type, inoculation time after treatment, and fungicide application site). Other active ingredients, including acibenzolar-S-methyl, dimethomorph, fenamidone, ethaboxam, mandipropamid, mefenoxam, and oxathiapiprolin, were most effective in reducing stem lesion growth in three to seven of the eight trial parameters evaluated. Compared to nontreated plants, stem lesion inhibition ranged from 84.1 to 100%. Data from these trials demonstrate the comparative effectiveness of tested products under controlled environmental conditions favorable for disease development; however, confirmation of these findings is required in field trials, where plant and environmental conditions will be variable. Accepted for publication 18 September 2014. Published 1 November 2014.

scholarly journals Incidence of Phytophthora Blight and Verticillium Wilt Within Chile Pepper Fields in New Mexico

Plant Disease ◽  
2006 ◽  
Vol 90 (3) ◽  
pp. 291-296 ◽  
Author(s):  
S. Sanogo ◽  
J. Carpenter
Keyword(s):  
New Mexico ◽  
Drip Irrigation ◽  
Phytophthora Capsici ◽  
Furrow Irrigation ◽  
Growth Stages ◽  
Phytophthora Blight ◽  
Chile Pepper ◽  
Plant Infection ◽  
Causative Agents ◽  
Pepper Plants

Statewide surveys of commercial chile pepper (Capsicum annuum) fields were conducted in New Mexico from 2002 to 2004 to gain information on the incidence of diseases with wilt symptoms and their causative agents. Fifty-nine fields were surveyed during the course of this 3-year study when chile pepper plants were at growth stages from green fruit to beginning red fruit. All fields were affected by diseases with wilt symptoms. The proportion of total field area exhibiting symptoms of wilt spanned from less than 1% to over 80%. Field diagnostics along with laboratory assays of wilted plants revealed that the wilting was caused by Phytophthora capsici and Verticillium dahliae. The two pathogens were both found in 80% of the fields, and occurred together in some wilted plants in 12% of the fields. Average incidence of plant infection (number of plants infected with P. capsici or V. dahliae out of 5 to 25 wilted plants sampled) varied from approximately 40 to 90% for P. capsici, and from 18 to 65% for V. dahliae. Incidence of plant infection by P. capsici was approximately 40% less in fields with drip irrigation than in fields with furrow irrigation. In contrast, incidence of plant infection by V. dahliae was approximately 32% greater under drip irrigation than under furrow irrigation. In pathogenicity tests, isolates of P. capsici and V. dahliae caused symptoms in inoculated chile pepper identical to those in field-grown chile pepper plants. Results indicate that diseases with wilt symptoms are well established in chile pepper production fields, with P. capsici and V. dahliae posing the most serious challenge to chile pepper producers in New Mexico.

scholarly journals Potential Sources of Resistance in U.S. Cucumis melo PIs to Crown Rot Caused by Phytophthora capsici

HortScience ◽  
2013 ◽  
Vol 48 (2) ◽  
pp. 164-170 ◽  
Author(s):  
Ryan S. Donahoo ◽  
William W. Turechek ◽  
Judy A. Thies ◽  
Chandrasekar S. Kousik
Keyword(s):  
Cucumis Melo ◽  
Phytophthora Capsici ◽  
Crown Rot ◽  
Fruit Rot ◽  
Broad Host Range ◽  
Post Inoculation ◽  
Vegetable Crops ◽  
Phytophthora Blight ◽  
Sources Of Resistance ◽  
Breeding Programs

Phytophthora capsici is an aggressive pathogen that is distributed worldwide with a broad host range infecting solanaceous, fabaceous, and cucurbitaceous crops. Over the past two decades, increased incidence of Phytophthora blight, particularly in eastern states, has threatened production of many vegetable crops. Cucumis melo L. (honeydew and muskmelon), although especially susceptible to fruit rot, is also highly susceptible to crown rot. Currently, little is known about host resistance to P. capsici in C. melo. To assess crown rot resistance in C. melo seedlings, 308 U.S. PIs, and two commercial cultivars (Athena and Dinero) were grown under greenhouse conditions. Seedlings with three to four true leaves were inoculated with a five-isolate zoospore suspension (1 × 104 zoospores per seedling) at the crown and monitored for 6 weeks. All the susceptible control plants of Athena died within 7 days post-inoculation. The majority of the PIs (281 of 308) were highly susceptible to crown rot and succumbed to the disease rapidly and had less than 20% of the plants survive. Several PIs (PI 181748, PI 182964, and PI 273438) succumbed to crown rot earlier than the susceptible melon cultivars. Eighty-seven PIs selected on the basis of the first screen were re-evaluated and of these PIs, 44 were less susceptible than cultivars Athena and Dinero. Twenty-five of the 87 PIs were evaluated again and of these six PI, greater than 80% of the plants survived in the two evaluations. Disease development was significantly slower on these PIs compared with the susceptible checks. High levels of resistance in S1 plants of PI 420180, PI 176936, and PI 176940 were observed, which suggests that development of resistant germplasm for use in breeding programs can be accomplished. Further screening and careful selection within each of these PIs can provide a framework for the development of resistant germplasm for use in breeding programs.

scholarly journals Heat Level in Chile Pepper in Relation to Root and Fruit Infection by Phytophthora capsici

HortScience ◽  
2008 ◽  
Vol 43 (6) ◽  
pp. 1846-1851 ◽  
Author(s):  
Mohammed B. Tahboub ◽  
Soumaila Sanogo ◽  
Paul W. Bosland ◽  
Leigh Murray
Keyword(s):  
New Mexico ◽  
Plant Disease ◽  
Phytophthora Capsici ◽  
Lesion Length ◽  
Phytophthora Blight ◽  
Chile Pepper ◽  
Systematic Assessment ◽  
Green Fruit ◽  
Relationship Of ◽  
The Relationship

Phytophthora blight, caused by Phytophthora capsici Leon., is a major plant disease that limits chile pepper (Capsicum annuum L.) production in New Mexico. Chile pepper producers in New Mexico report that Phytophthora blight symptoms appear to develop slower and its incidence is lower in hot than in nonhot chile pepper cultivars. There has been no previous systematic assessment of the relationship of chile pepper heat level to chile pepper response to P. capsici. Three hot (‘TAM-Jalapeño’, ‘Cayenne’, and ‘XX-Hot’) and two low-heat (‘NuMex Joe E. Parker’ and ‘New Mexico 6-4’) chile pepper cultivars were inoculated at the six- to eight-leaf stage with zoospores of P. capsici under greenhouse conditions. Additionally, detached mature green fruit from three hot (‘TAM-Jalapeño’, ‘Cayenne’, and ‘XX-Hot’) and one low-heat (‘AZ-20’) chile pepper cultivars were inoculated with mycelium plugs of P. capsici under laboratory conditions. When plant roots were inoculated, Phytophthora blight was slowest to develop on ‘TAM-Jalapeño’ in contrast to all other cultivars. All ‘TAM-Jalapeño’ plants showed wilting symptoms or were dead ≈22 days after inoculation compared with 18, 15, 14, and 11 days for ‘NuMex Joe E. Parker’, ‘New Mexico 6-4’, ‘XX-Hot’, and ‘Cayenne’, respectively. When fruit were inoculated, lesion length ratio was significantly higher for ‘TAM-Jalapeño’ fruit than for ‘Cayenne’, ‘XX-Hot’, and ‘AZ-20’ fruit. Similarly, lesion diameter ratio was higher for ‘TAM-Jalapeño’ fruit than for fruit of other cultivars. Furthermore, mycelial growth on lesion surfaces was more extensive on ‘TAM-Jalapeño’ fruit than on fruit of other cultivars. Results from this study indicate that there is little or no relationship between heat level and chile pepper root and fruit infection by P. capsici.

Efficacy of Pecan Husk and Shell Phenolic Extracts Against Phytophthora Blight in Chile Pepper

2021 ◽  
Author(s):  
Phillip A Lujan ◽  
Srijana Dura ◽  
Ivette Guzman ◽  
Mary Grace ◽  
Mary Lila ◽  
...  
Keyword(s):  
High Performance ◽  
Phytophthora Capsici ◽  
Dry Weight ◽  
Control Treatment ◽  
Phytophthora Blight ◽  
Water Control ◽  
Resistance Response ◽  
Chile Pepper ◽  
Extraction Solvent ◽  
Phenolic Extracts

Phytophthora blight, caused by Phytophthora capsici, is detrimental to chile peppers (Capsicum spp.). In this study, phenolics extracted from pecan (Carya illinoinensis) husk and shell, were foliarly applied to chile pepper (Capsicum annuum L., cultivar NM 6-4) to induce a resistance response against plant infection by P. capsici. Several pecan metabolite extractions were tested, and an acetic acid (2%) in aqueous methanol (80%) solution was the best extraction solvent, yielding total polyphenolic content of 290 mg/g dry weight from husk and 641 mg/g from shell. The phenolic extracts from husk and shell were applied as foliar sprays at different concentrations to chile plants inoculated with a virulent isolate of P. capsici. Chile plants treated with 1% phenolic husk or shell extracts or 0.1% salicylic acid remained alive throughout the study while plants subjected to all other treatments (including a water control treatment) died. Analyses of the extracts through spectrophotometry and high performance liquid chromatography indicated that the phenolic content in the extracts was largely made up of proanthocyanidins also known as condensed tannins. Pecan byproducts may be used as additional options for management of Phytophthora blight.

scholarly journals Phytophthora Blight Caused by Phytophthora capsici on Pumpkin and Winter Squash in Texas

Plant Disease ◽  
2007 ◽  
Vol 91 (5) ◽  
pp. 633-633 ◽  
Author(s):  
T. Isakeit
Keyword(s):  
Phytophthora Capsici ◽  
Morphological Characteristics ◽  
Lima Bean ◽  
The United States ◽  
Fruit Rot ◽  
High Plains ◽  
Phytophthora Blight ◽  
Lower Rio Grande Valley ◽  
Production Areas ◽  
Winter Squash

Phytophthora blight of pumpkin and squash (Cucurbita spp.) has increased in importance in many production areas of the United States in recent years. This disease was seen on a 36-ha commercial field of several cultivars of pumpkin and winter squash (including Cucurbita maxima cvs. Prizewinner, Atlantic Giant, and Casper and C. pepo cvs. Howden, Festival, Sweet Dumpling, and Magic Lantern) in Yoakum County in the High Plains of Texas during August of 2006. At that time, 2% of the field was affected. A month later, after unusually frequent rain showers and higher-than-average precipitation, 78% of the field was lost in spite of an aggressive fungicide program following the initial diagnosis. Symptoms consisted of white, velvety growth on fruit, fruit rot, leaf blight, and wilt. Sporangia on fruit were papillate, ovoid to ellipsoid, and measured 37 to 40 × 21 to 23 μm. Isolations were made from tissue onto water agar and two isolates used for further study were maintained on corn meal agar. When isolates were paired on V8 agar with two Phytophthora capsici isolates from pepper (3) of opposite mating type, amphigynous antheridia and plerotic oospores 25 to 27 μm in diameter were produced. The morphological characteristics of the isolates were consistent with P. capsici (1). Four-week-old plants of C. maxima cv. Cinderella and C. pepo cvs. Festival and Sweet Dumpling growing in Metro-Mix 366 were inoculated with each isolate by placing 2 cm3 of a 6-week-old culture from lima bean agar (0.2% agar) adjacent to the base of each stem. The soil was then watered to saturation. There were four plants per 2.8-liter pot and two pots per isolate-cultivar combination. Plants were grown in the greenhouse at 18 to 27°C. The test was repeated once. Wilting and stem collapse were seen on inoculated plants 2 to 7 days later, sometimes with production of sporangia on stems. The pathogen was consistently reisolated from symptomatic plants, fulfilling Koch's postulates. These isolates were also pathogenic to pepper (Capsicum annuum). The affected field had been planted to pumpkins and winter squash the previous year when the grower saw similar symptoms on a few plants. In 2004, this field was planted to wheat. There are 1,350 ha of pumpkins produced in Texas, mostly in High Plains counties, and 730-ha squash produced throughout the state. To my knowledge, this is the first report of Phytophthora blight on pumpkin and winter squash in Texas. Phytophthora blight has been a long-standing problem of peppers grown in the Lower Rio Grande Valley of Texas (2), which is 900 km from Yoakum County. References: (1) D. C. Erwin and O. K. Ribeiro. Phytophthora Diseases Worldwide. The American Phytopathological Society. St. Paul, MN. 1996. (2) G. H. Godfrey. Plant Dis. Rep. 31:8, 1947. (3) B. Villalon. Phytopathology (Abstr.) 86(suppl):S118, 1996.

scholarly journals Effectiveness of Nine Different Fungicides for Management of Crown and Root Rot of Chile Pepper Plants Caused by Phytophthora capsici

2015 ◽  
Vol 16 (4) ◽  
pp. 218-222 ◽  
Author(s):  
Michael E. Matheron ◽  
Martin Porchas
Keyword(s):  
Root Rot ◽  
Phytophthora Capsici ◽  
Field Trials ◽  
Pepper Plant ◽  
Plant Mortality ◽  
Phytophthora Blight ◽  
Chile Pepper ◽  
Fungicide Application ◽  
Crown And Root Rot ◽  
Pepper Plants

Bell and chile pepper plants are affected by the economically important disease Phytophthora blight, which is caused by the oomycete pathogen Phytophthora capsici. Greenhouse and field trials were conducted to evaluate and compare the ability of nine different fungicides to reduce development of the crown and root rot phase of Phytophthora blight and the resulting chile pepper plant death when applied at 2- and 4-week intervals. Overall, chile pepper plant mortality was significantly decreased in three greenhouse trials with soil applications of fungicide products containing ametoctradin + dimethomorph, cyazofamid, dimethomorph, ethaboxam, fluazinam, fluopicolide, mandipropamid, mefenoxam, and oxathiapiprolin. The same fungicides, excluding mandipropamid and oxathiapiprolin, also significantly reduced overall plant mortality in two field trials. No significant difference was found between 2- and 4-week fungicide application intervals with respect to chile pepper plant survival in any greenhouse or field trial. In general, the degree of reduction in chile pepper plant mortality was lower in field compared to greenhouse trials, probably due to the respective soil surface spray compared to soil drench method of fungicide application used in each instance. Accepted for publication 17 November 2015. Published 30 November 2015.

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