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.

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 Performance and Resistance to Phytophthora Crown and Root Rot in Squash Lines

2020 ◽  
Vol 30 (5) ◽  
pp. 608-618 ◽  
Author(s):  
Kyle E. LaPlant ◽  
Gregory Vogel ◽  
Ella Reeves ◽  
Christine D. Smart ◽  
Michael Mazourek
Keyword(s):  
Root Rot ◽  
Cucurbita Pepo ◽  
Field Experiments ◽  
Phytophthora Capsici ◽  
Severe Disease ◽  
Field Trials ◽  
Disease Symptoms ◽  
Resistant Lines ◽  
Oomycete Pathogen ◽  
Crown And Root Rot

Phytophthora crown and root rot, caused by the oomycete pathogen Phytophthora capsici, is a devastating disease of squash and pumpkin (Cucurbita pepo). No currently available cultivars provide complete resistance to this disease. Three newly developed squash lines and four hybrids were evaluated in greenhouse and field experiments for their resistance to phytophthora crown and root rot as well as for their horticultural performance. The three newly developed lines ranked among the most resistant entries included in 2 years of field trials. In addition, in a separate greenhouse experiment, one of the lines was shown to display the least severe disease symptoms among a group of accessions previously reported to possess partial resistance to phytophthora crown and root. Furthermore, the resistance was observed to be robust to several isolates of P. capsici. However, the phytophthora-resistant lines had reduced yield relative to standard squash cultivars. These lines are useful for continued breeding efforts toward a phytophthora crown and root rot-resistant cultivar.

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 Suppression of Phytophthora Root and Crown Rot on Pepper Plants Treated with Acibenzolar-S-Methyl

Plant Disease ◽  
2002 ◽  
Vol 86 (3) ◽  
pp. 292-297 ◽  
Author(s):  
M. E. Matheron ◽  
M. Porchas
Keyword(s):  
Phytophthora Capsici ◽  
Stem Canker ◽  
Crown Rot ◽  
Management Tool ◽  
Disease Development ◽  
Phytophthora Blight ◽  
Chile Pepper ◽  
Bell Tower ◽  
Root And Crown Rot ◽  
Pepper Plants

The fungicide mefenoxam is registered for the control of Phytophthora blight of peppers caused by Phytophthora capsici. Isolates of the pathogen that are insensitive to mefenoxam, however, have been detected in some locations. Consequently, alternative methods are needed to control Phytophthora blight of peppers. Acibenzolar-S-methyl (ABM, Actigard) is a chemical activator of plant disease resistance that has potential for the management of Phytophthora blight of peppers. The effect of foliar applications of ABM on the development of root and crown rot on pepper plants grown in the greenhouse and inoculated with Phytophthora capsici or in soil naturally infested with the pathogen was evaluated. Inhibition of stem canker development on pepper cvs. Bell Tower and AZ9 after four treatments with ABM (75 μg/ml) was significantly greater than on plants receiving a single application of the chemical. Stem canker length on Bell Tower or AZ9 peppers was inhibited by 93.2 to 97.2% and 87.4 to 92.4% when plants were inoculated with P. capsici at 1 or 5 weeks, respectively, after the fourth application of ABM. Survival of chile pepper plants grown in field soil naturally infested with P. capsici was significantly increased by three foliar applications of ABM (75 μg/ml) compared with nontreated plants in all three trials when pots were watered daily and in two of three trials when pots were flooded for 48 h every 2 weeks. When soil was flooded every 2 weeks to establish conditions highly favorable for disease development, plants treated once with mefenoxam (100 μg/ml) survived significantly longer than those treated with ABM. On the other hand, when water was provided daily without periodic flooding to establish conditions less favorable for disease development, plant survival between the two chemicals was not different in two of three trials. Length of survival among chile pepper plants treated twice with 25, 50, or 75 μg/ml of ABM and grown in soil infested with P. capsici was not different. This work indicates that ABM could be an important management tool for Phytophthora root and crown rot on pepper plants.

scholarly journals Integrated Control of Rhizoctonia Crown and Root Rot of Sugar Beet with Fungicides and Antagonistic Bacteria

Plant Disease ◽  
2001 ◽  
Vol 85 (7) ◽  
pp. 718-722 ◽  
Author(s):  
Sebastian Kiewnick ◽  
Barry J. Jacobsen ◽  
Andrea Braun-Kiewnick ◽  
Joyce L. A. Eckhoff ◽  
Jerry W. Bergman
Keyword(s):  
Sugar Beet ◽  
Root Rot ◽  
Integrated Control ◽  
The United States ◽  
Field Trials ◽  
Sugar Yield ◽  
Economic Losses ◽  
Yield Increase ◽  
Leaf Stage ◽  
Crown And Root Rot

Rhizoctonia crown and root rot, caused by the fungus Rhizoctonia solani AG 2-2, is one of the most damaging sugar beet diseases worldwide and causes significant economic losses in more than 25% of the sugar beet production area in the United States. We report on field trials in the years 1996 to 1999 testing both experimental fungicides and antagonistic Bacillus sp. for their potential to reduce disease severity and increase sugar yield in trials inoculated with R. solani AG 2-2. Fungicides were applied as in-furrow sprays at planting or as band sprays directed at the crown at the four-leaf stage, or four- plus eight-leaf stage, while bacteria were applied at the four-leaf stage only. The fungicides azoxystrobin and tebuconazole reduced crown and root rot disease by 50 to 90% over 3 years when used at rates of 76 to 304 g a.i./ha and 250 g a.i./ha, respectively. The disease index at harvest was reduced and the root and sugar yield increased with azoxystrobin compared with tebuconazole. The combination of azoxystrobin applied at 76 g a.i./ha and the Bacillus isolate MSU-127 resulted in best disease reduction and greatest root and sucrose yield increase.

scholarly journals Evaluation of Trichoderma harzianum for controlling root rot caused by Phytophthora capsici in pepper plants

1999 ◽  
Vol 48 (1) ◽  
pp. 58-65 ◽  
Author(s):  
A. Sid Ahmed ◽  
C. Perez-Sanchez ◽  
C. Egea ◽  
M. E. Candela
Keyword(s):  
Trichoderma Harzianum ◽  
Root Rot ◽  
Phytophthora Capsici ◽  
Pepper Plants

scholarly journals Pythium spp. Associated with Bell Pepper Production in Florida

Plant Disease ◽  
2000 ◽  
Vol 84 (12) ◽  
pp. 1271-1274 ◽  
Author(s):  
D. O. Chellemi ◽  
D. J. Mitchell ◽  
M. E. Kannwischer-Mitchell ◽  
P. A. Rayside ◽  
E. N. Rosskopf
Keyword(s):  
Root Rot ◽  
Production Systems ◽  
Bell Pepper ◽  
Root Tip ◽  
Root Weight ◽  
Plant Mortality ◽  
Fresh Market ◽  
Plant Weight ◽  
Pathogenicity Tests ◽  
Pepper Plants

Ten species of Pythium and a group of isolates that produced filamentous sporangia but did not form sexual structures (Pythium ‘group F’) were recovered from the root systems of fresh market bell pepper plants grown on polyethylene-mulched production systems in Florida. Pathogenicity tests using pasteurized field soil inoculated with infested wheat seed demonstrated that P. aphanidermatum, P. myriotylum, P. helicoides, and P. splendens can cause significant root rot and reductions in root growth of pepper. P. aphanidermatum and P. myriotylum caused the most severe root rot, the greatest reductions in plant weight, and 42 and 62% plant mortality, respectively. In pathogenicity tests with tomato plants, these four species produced similar plant weight losses and disease ratings to those observed in pepper, but little or no plant mortality. Low incidences of root tip necrosis in pepper plants were observed with P. arrhenomanes, P. catenulatum, P. graminicola, and P. irregulare, but none of these species caused losses in root weight and only P. irregulare reduced shoot weight. P. periplocum, P. spinosum, and Pythium sp. F colonized root tissue of pepper but caused no significant root rot and did not adversely affect growth. Similar trends were observed with tomato, except that P. arrhenomanes caused limited root tip necrosis without affecting plant growth and P. catenulatum, P. graminicola, P. irregulare, P. spinosum, and Pythium sp. F colonized at least some of the plants but did not cause root disease. A significant interaction between temperature and P. aphanidermatum or P. myriotylum was observed on pepper transplants. The greatest reductions in growth occurred at 28°C, whereas plant mortality only occurred at 34°C.

scholarly journals Resistance of Pepper to Phytophthora Crown, Root, and Fruit Rot Is Affected by Isolate Virulence

Plant Disease ◽  
2010 ◽  
Vol 94 (1) ◽  
pp. 24-30 ◽  
Author(s):  
J. M. Foster ◽  
M. K. Hausbeck
Keyword(s):  
Root Rot ◽  
Laboratory Experiments ◽  
Phytophthora Capsici ◽  
Fruit Rot ◽  
Hot Pepper ◽  
Cultivar Resistance ◽  
Breeding Lines ◽  
Pepper Fruit ◽  
Millet Seed ◽  
Crown And Root Rot

Greenhouse and laboratory experiments were conducted to determine the virulence of four Phytophthora capsici isolates from Michigan to 31 bell and hot pepper cultivars and breeding lines. Resistance to crown and root rot was assessed following the inoculation of soilless media with P. capsici–infested millet seed. In a detached fruit assay, fruit rot resistance was evaluated following inoculation with zoospore suspensions of 1.75 × 106 zoospores/ml. The four isolates differed in virulence to pepper lines screened for crown and root rot resistance and were considered to be four different physiological races. The pepper lines CM334, NY07-8001, NY07-8006, and NY07-8007 were resistant to the isolates tested. None of the commercial cultivars were resistant to P. capsici isolate 12889, but several cultivars were resistant to the other isolates screened. The isolates varied in their ability to cause infection on the fruits of the different cultivars. Overall, pepper fruit were more susceptible to P. capsici than the roots and crowns. Management of Phytophthora crown and root rot of pepper can be improved through the use of resistant cultivars. However, since isolate virulence affects resistance, cultivar resistance will need to be utilized on a local scale accordingly.

scholarly journals Genetic Analysis of Phytophthora Root Rot Race-specific Resistance in Chile Pepper

2008 ◽  
Vol 133 (6) ◽  
pp. 825-829 ◽  
Author(s):  
Ariadna Monroy-Barbosa ◽  
Paul W. Bosland
Keyword(s):  
Root Rot ◽  
Recombinant Inbred Lines ◽  
Single Gene ◽  
Phytophthora Capsici ◽  
Segregation Ratio ◽  
Descent Method ◽  
Chile Pepper ◽  
Phytophthora Root Rot ◽  
Multiple Alleles ◽  
Seven Generations

Phytophthora capsici Leon., causal agent of phytophthora root rot, is one of the most devastating pathogens attacking chile pepper (Capsicum annuum L.) plants. Many studies have tried to better understand phytophthora resistance, but the genetic behavior is not completely understood. To determine if phytophthora root rot resistance in chile pepper is controlled by multiple alleles at a few loci, or multiple genes at different loci, five recombinant inbred lines (RILs) were evaluated. The resistant accession, Criollo de Morelos-334, and the susceptible cultivar, Early Jalapeno, were hybridized to develop multiple RILs. After seven generations of selfing using the single seed descent method, four RILs were selected based on their phenotypic response to inoculation by five P. capsici isolates. The RILs were hybridized to each other to obtain F1 and F2 populations. The F2 populations were inoculated with single and a pair of races of P. capsici. When the F2 populations were inoculated with a single race, ratios of three resistant:one susceptible were obtained in the majority of the populations, indicating the action of an independent single gene. When the F2 populations were inoculated with a combination of two races, segregation ratios of 15 resistant:one susceptible were observed in two populations out of the four populations. The presence of susceptible individuals in all of the F2 population indicates that the resistant genes for the different P. capsici races are located at different loci. However, the rejection of the segregation ratio in one of the F2 population under a single race inoculation and in two of the F2 populations challenged with a combination of two races suggest a linkage phenomenon between some of the R genes. None of the RILs evaluated in this study displayed allelism for phytophthora root rot resistance.

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