A field evaluation of jalapeño and non-jalapeño chile pepper resistance to Phytophthora blight caused by Phytophthora capsici

2021 ◽  
Author(s):  
Srijana Dura ◽  
Phillip A Lujan ◽  
Ivette Guzman ◽  
Robert Steiner ◽  
Soum Sanogo
Keyword(s):  
Disease Incidence ◽  
Phytophthora Capsici ◽  
Field Evaluation ◽  
Severity Index ◽  
Vegetable Crops ◽  
Phytophthora Blight ◽  
Inoculum Level ◽  
Chile Pepper ◽  
Progress Curve ◽  
Stage Disease

Phytophthora capsici is a destructive soilborne pathogen, which causes Phytophthora blight in many vegetable crops including chile pepper (Capsicum sp.). Our research was aimed at evaluating the resistance of jalapeño cultivars in field conditions and identifying the factors associated with reduction of Phytophthora blight caused by P. capsici. Six jalapeño (NuMex Orange Spice, NuMex Pumpkin Spice, NuMex Jalmundo, TAM Jalapeño, Early Jalapeño, and NuMex Vaquero) and two non-jalapeño (CM-334 and NM 6-4) cultivars were inoculated with P. capsici at the fruiting stage. Disease severity index (DSI), disease incidence (DI), and area under the disease progress curve (AUDPC) for each cultivar were measured. The most susceptible jalapeño cultivars with the highest DSI, DI, and AUDPC were NuMex Orange Spice, NuMex Jalmundo and NuMex Pumpkin Spice, whereas the least susceptible jalapeño cultivars were Early Jalapeño, TAM Jalapeño, and NuMex Vaquero, with the lowest DSI, DI, and AUDPC. The identified jalapeños with reduced susceptibility to Phytophthora blight can be planted in infested fields, combined with other control methods which may help in soil disinfestation by reducing the inoculum level in soil over time.

scholarly journals Applying Drone-based Spatial Mapping to Help Growers Manage Crop Diseases

2021 ◽  
Author(s):  
Qingren Wang ◽  
Shouan Zhang
Keyword(s):  
Disease Incidence ◽  
Phytophthora Capsici ◽  
Cost Effective ◽  
Labor Cost ◽  
Spatial Mapping ◽  
Vegetable Crops ◽  
Yield Losses ◽  
Phytophthora Blight ◽  
Rapid Spread ◽  
Wet Weather

Phytophthora blight (Phytophthora capsici) is one of the major soilborne diseases threatening many vegetable crops including squash. The disease results in severe epidemics and yield losses due to a rapid spread of the pathogen associated with wet weather and soil waterlogging. Implementing drone-based spatial mapping with software elevation tools can assist growers in evaluating land levelling for uniform distribution of water to mitigate potential disease incidence. The technology has great advantages: rapid, precise, and labor-cost effective. Our result can implicate Extension professionals with application of spatial mapping to assist growers in managing their land and crops for disease control efficiently.

Genetic analysis of Okra Yellow Vein Mosaic Virus disease resistance in wild relative of okra Abelmoschus angulosus Wall. ex Wight & Arn

2019 ◽  
Vol 17 (04) ◽  
pp. 346-351
Author(s):  
SamanthiKumari Wasala ◽  
Sumudu I. Senevirathne ◽  
Jayantha Bandara Senanayake ◽  
Anuradini Navoditha
Keyword(s):  
Disease Resistance ◽  
Mosaic Virus ◽  
Disease Severity ◽  
Virus Disease ◽  
Disease Incidence ◽  
Severity Index ◽  
Yellow Vein ◽  
Wild Relative ◽  
Yellow Vein Mosaic Virus ◽  
Progress Curve

AbstractWild relative of okra, Abelmoschus angulosus Wall. ex Wight & Arn. was identified as a resistant germplasm for Okra Yellow Vein Mosaic Virus (OYVMV) which is the devastating disease for okra cultivation in Sri Lanka. The mode of resistance of OYVMV in A. angulosus was studied with the aim of tagging responsible genes for the disease resistance. Wide hybridization was performed between A. angulosus and highly virus susceptible A. esculentus variety, MI-7. Very poor seed setting was observed in F1 and F2 generations due to post zygotic abortion. Disease screening was carried out using F1 and F2:3 populations along with parents in the field under induced disease pressure. Disease severity index and area under disease progress curve were calculated to measure disease severity. Number of genes segregating for OYVMV disease resistance was calculated for the F2:3 generation. Modified Wright's formula was used to estimate the effective gene number and mode of inheritance by a quantitative method. A χ2 test was performed for qualitative analysis. Plants of A. angulosus were totally free of virus incidence while 100% disease incidence was observed in the variety MI-7. F2:3 population showed between and within progeny segregation for disease incidence. Results indicated that the disease susceptibility was dominant over resistance. χ2 analysis revealed that the segregation of disease severity was significantly fit to the gene model of 9:6:1 (χ2 = 0.1757 at P ≤ 0.05) suggesting the disease resistance in A. angulosus is governing by two recessive genes in an additive manner. Result was confirmed by the quantitative analysis.

scholarly journals Sensitivity of Phytophthora capsici on Vegetable Crops in Georgia to Mandipropamid, Dimethomorph, and Cyazofamid

Plant Disease ◽  
2012 ◽  
Vol 96 (9) ◽  
pp. 1337-1342 ◽  
Author(s):  
K. L. Jackson ◽  
J. Yin ◽  
P. Ji
Keyword(s):  
Disease Management ◽  
Mycelial Growth ◽  
Phytophthora Capsici ◽  
Chemical Compounds ◽  
Bell Pepper ◽  
Vegetable Production ◽  
Vegetable Crops ◽  
Phytophthora Blight ◽  
Significant Component ◽  
Serious Disease

Phytophthora blight, caused by Phytophthora capsici, is a serious disease in vegetable production, and selective use of fungicides continues to be a significant component of disease management programs. The effect of three chemical compounds—mandipropamid, dimethomorph, and cyazofamid—on asexual stages of P. capsici collected from bell pepper and cucurbits in Georgia was assessed in this study. Forty isolates of P. capsici were determined to be sensitive to mandipropamid and dimethomorph based on mycelial growth, zoospore germination, and sporangial production. Concentrations that were 50% effective (EC50 values) of mandipropamid that inhibited mycelial growth, zoospore germination, and sporangial production of the isolates averaged 0.03, 5.70, and 0.02 μg/ml, respectively. EC50 values of dimethomorph in inhibiting mycelial growth, zoospore germination, and sporangial production averaged 0.24, 0.10, and 0.46 μg/ml, respectively. The majority of isolates were either resistant or intermediately sensitive to cyazofamid at 500 μg/ml or lower concentrations based on mycelial growth or sporangial production, although all the isolates were sensitive to this compound based on zoospore germination, with an average EC50 of 0.04 μg/ml. The results indicated that P. capsici populations in Georgia have not developed resistance to mandipropamid and dimethomorph whereas, for the majority of the isolates, certain asexual stages were resistant to cyazofamid.

scholarly journals In vitro, In vivo and In situ, Effect of Mancozeb 80 WP on Colletotrichum gloeosporioides (Penz.) Penz. and Sacc., Causative Agent of Anthracnose of Cashew (Anacardium occidentale L.) in Chad and Cameroon

2021 ◽  
pp. 1-14
Author(s):  
Ngoh Dooh Jules Patrice ◽  
Deurnaye Placide ◽  
Abdoul Madjerembe ◽  
Mbou T. Pavel Rony ◽  
Djongnang Gabriel ◽  
...  
Keyword(s):  
Radial Growth ◽  
Colletotrichum Gloeosporioides ◽  
Disease Incidence ◽  
Severity Index ◽  
Anacardium Occidentale ◽  
In Vivo Experiments ◽  
Progress Curve ◽  
Cashew Tree

Aims: The aim of this work was to evaluate effect of Mancozeb 80 WP against Colletotrichum gloeosporioides, the agent responsible of anthracnose of cashew tree (Anacardium occidentale  L.). Study Design: The experimental design was in completely randomized blocks with three replications. Place and Duration of Study: in vitro and in vivo experiments were performed in Laboratory of  Department of Biological Sciences, University of Maroua during six months. Field trial was carried out in Kelo, Chad during three months. Methodology: Isolates were obtained from diseased organs (leaves and fruits) from Kélo in Chad and Maroua in Cameroon. The concentrations used in the laboratory were C1 (5 mg/ml), C2 (0.5 mg/ml), C3 (0.05 mg/ml), C4 (0.005 mg/ml), C5 (0.0 mg/ml). Radial growth, sporulation, conidial germination and pathogenicity were used to characterize and evaluate the effect of Mancozeb on the isolates in vitro. The preventive test was performed on three-month-old plants previously treated with Mancozeb. The concentration of 5 g/l was applied to the field and the incidence and severity were used to calculate the AUIPC (Area Under Disease Incidence Progress Curve) and AUSiPC (Area Under Disease Severity Index Progress Curve) curves. Results: Mancozeb reduced radial growth of all isolates at concentrations C1 (5 mg/ml), C2 (0.5 mg/ml) and C3 (0.05 mg/ml). The percentages of inhibition ranged from 50 to 100%. Mancozeb 80 WP completely (100%) inhibited the germination of C. gloeosporioides conidia in vitro. Mancozeb has protected cashew plants in vivo at the concentration C1 (5 mg/ml). AUIPC and AUSiPC were higher on control plants and lower on Mancozeb-treated plants. Conclusion: Mancozeb 80 WP may be associated in integrated pest management strategy against anthracnose.

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.

Detection of Phytophthora capsici from irrigation ponds in South Georgia

2021 ◽  
Author(s):  
Owen Hudson ◽  
Sumyya Waliullah ◽  
Pingsheng Ji ◽  
Justin Hand ◽  
Jake Price ◽  
...  
Keyword(s):  
Phytophthora Capsici ◽  
Disease Outbreaks ◽  
Lamp Assay ◽  
Control Measures ◽  
Vegetable Crops ◽  
Phytophthora Blight ◽  
Filtration Method ◽  
South Georgia ◽  
Detection And Identification ◽  
Wide Range

Phytophthora capsici, the causal agent of Phytophthora blight, is a prominent and economically damaging oomycete pathogen in South Georgia. P. capsici causes crown, root, leaf, stem, and fruit infections on a wide range of vegetable crops. Oomycete pathogens such as P. capsici are dispersed in water as their zoospores are flagellated and can move through runoff. Irrigation ponds are often reservoirs for different pathogens and reusing the captured runoff is increasing in popularity to decrease irrigation costs. This combination allows for unintended outbreaks of diseases by pumping the contaminated runoff onto susceptible crops. Detection and identification of these pathogens is a crucial step in disease management and rapid detection can ensure timely application of disease control measures. In this study, 42 irrigation ponds in nine counties from South Georgia were surveyed for the presence of P. capsici using a novel filtration method in conjunction with a LAMP assay specific for P. capsici. Ten ponds in five counties were found to have P. capsici as detected from the assay, suggesting that testing of irrigation ponds for P. capsici and other pathogens should be conducted to assist in preventing disease outbreaks.

Genetic Architecture of Chile Pepper (Capsicum Spp.) QTLome Revealed Using Meta-QTL Analysis

2021 ◽  
Author(s):  
Dennis N. Lozada ◽  
Lanie Whelpley ◽  
Andrea Acuña-Galindo
Keyword(s):  
Qtl Analysis ◽  
Genetic Architecture ◽  
Meta Analysis ◽  
Phytophthora Capsici ◽  
Snp Markers ◽  
Vegetable Crops ◽  
Chile Pepper ◽  
Breeding Populations ◽  
Capsicum Spp ◽  
Chile Peppers

Abstract Chile peppers (Capsicum spp.) are among the most important vegetable crops in the world due to their health-related, economic, and industrial uses. In recent years, quantitative trait loci (QTL) mapping approaches have been widely implemented to identify genomic regions affecting variation for different traits for marker-assisted selection (MAS) in peppers. Meta-QTL analysis for different traits in Capsicum remains lacking, and therefore it would be necessary to re-evaluate identified QTL for a more precise MAS for genetic improvement. We report the first known meta-QTL analysis for diverse traits in the chile pepper QTLome. A literature survey using 29 published linkage mapping studies identified 766 individual QTL from five different trait classes. A total of 311 QTL were projected into a consensus map. Meta-analysis identified 30 meta-QTL regions distributed across the 12 chromosomes of Capsicum. MQTL5.1 and MQTL5.2 related to Phytophthora capsici fruit and root rot resistance were delimited to < 1.0 cM confidence intervals in chromosome P5. Candidate gene analysis for the flanking sequences for the P5 meta-QTL revealed biological functions related to DNA repair and transcription regulation. Moreover, epigenetic mechanisms such as histone and RNA methylation and demethylation were predicted, indicating the potential role of epigenetics for P. capsici resistance. Allele specific SNP markers for the meta-QTL will be developed and validated using different breeding populations of Capsicum for MAS of P. capsici resistant lines. Altogether, results from meta-QTL analysis for chile pepper QTLome rendered further insights into the genetic architecture of different traits for this valuable horticultural crop.

scholarly journals Pathogenicity of Phytophthora capsici to Brassica Vegetable Crops and Biofumigation Cover Crops (Brassica spp.)

Plant Disease ◽  
2015 ◽  
Vol 99 (12) ◽  
pp. 1721-1726 ◽  
Author(s):  
Charles S. Krasnow ◽  
Mary K. Hausbeck
Keyword(s):  
Cover Crops ◽  
Disease Incidence ◽  
Phytophthora Capsici ◽  
Fruit Rot ◽  
Vegetable Crops ◽  
Persistent Problem ◽  
Oilseed Radish ◽  
Brassica Spp ◽  
Brassica Vegetable ◽  
Brassicaceae Family

The soilborne oomycete Phytophthora capsici causes root, crown, and fruit rot of many vegetable crops in the Cucurbitaceae and Solanaceae families. P. capsici is a persistent problem in vegetable fields due to long-lived oospores that survive in soil and resist weathering and degradation. Vegetable crops in the Brassicaceae family have been considered nonhosts of P. capsici and are planted as rotational crops in infested fields. Brassica spp. are also grown as biofumigation cover crops to reduce inoculum levels of P. capsici and other soilborne pathogens, and this use has increased concurrent with restrictions on soil fumigation. Oriental mustard (Brassica juncea), oilseed rape (B. napus), and oilseed radish (Raphanus sativus var. oleiferus) contain high levels of glucosinolates and are widely recommended for biofumigation and as cover crops. The objective of this study was to evaluate vegetables and biofumigation cover crops in the Brassicaceae family for susceptibility to P. capsici. Brassica spp. used as vegetable crops and for biofumigation were grown in P. capsici-infested potting soil in the greenhouse and disease incidence and severity were recorded. In greenhouse trials, infection by the pathogen reduced the fresh weight of all Brassica spp. tested and resulted in plant death of 44% of plants of B. juncea ‘Pacific Gold’. P. capsici isolates exhibited differences in virulence (P < 0.0001), and were reisolated from the roots of all Brassica spp. included in the study. The biofumigation cover crop Pacific Gold mustard may not reduce populations of P. capsici in soil and, instead, may sustain or increase pathogen levels. Further research is necessary to test this possibility under field conditions.

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.

Sign in / Sign up

Export Citation Format

Share Document