scholarly journals Interactive Effects of Two Soilborne Pathogens, Phytophthora capsici and Verticillium dahliae, on Chile Pepper

2007 ◽  
Vol 97 (1) ◽  
pp. 37-43 ◽  
Author(s):  
S. Sanogo
Keyword(s):  
Verticillium Dahliae ◽  
Mycelial Growth ◽  
Phytophthora Capsici ◽  
Interactive Effects ◽  
Growth Media ◽  
Soilborne Pathogens ◽  
Single Plant ◽  
Chile Pepper ◽  
Stem Necrosis ◽  
Pepper Plants

Phytophthora capsici and Verticillium dahliae are two mycelial microorganisms associated with wilt symptoms on chile pepper (Capsicum annuum). Both pathogens occur in the same field and can infect a single plant. This study examined the nature of the co-occurrence of P. capsici and V. dahliae. Chile pepper plants were inoculated with each pathogen separately or with both pathogens concomitantly or sequentially. In concomitant inoculations, plants were inoculated with a mixture of zoospores of P. capsici and conidia of V. dahliae. In sequential inoculations, plants were inoculated with zoospores of P. capsici 4 days prior to inoculation with conidia of V. dahliae, or plants were inoculated with conidia of V. dahliae 4 days prior to inoculation with zoospores of P. capsici. Stem necrosis and leaf wilting were visible 3 to 4 days earlier in plants inoculated with both P. capsici and V. dahliae than in plants inoculated with P. capsici alone. Stem necrosis and generalized plant wilting were observed in plants inoculated with P. capsici alone, and stem necrosis, generalized plant wilting, and vascular discoloration were observed in plants inoculated with both P. capsici and V. dahliae by 21 days after inoculation. These symptoms were not observed in control plants or plants inoculated with V. dahliae alone. The frequency of recovery of V. dahliae from stems was ≈85 to 140% higher across inoculum levels when plants were inoculated with both P. capsici and V. dahliae than when plants were inoculated by V. dahliae alone. Similarly, the frequency of recovery of V. dahliae from roots was ≈13 to 40% higher across inoculum levels when plants were inoculated with both P. capsici and V. dahliae than when plants were inoculated by V. dahliae alone. There was no apparent antagonism between the two pathogens when they were paired on growth media. In general, when P. capsici and V. dahliae were paired on growth media, mycelial growth of each pathogen grown alone was not significantly different from mycelial growth when the pathogens were paired. Results suggest that wilt development is hastened by the presence of both P. capsici and V. dahliae in the same plants. The presence of P. capsici and V. dahliae in the same inoculum court enhanced infection and colonization of chile pepper by V. dahliae.

scholarly journals Response of Chile Pepper to Phytophthora capsici in Relation to Soil Salinity

Plant Disease ◽  
2004 ◽  
Vol 88 (2) ◽  
pp. 205-209 ◽  
Author(s):  
S. Sanogo
Keyword(s):  
Radial Growth ◽  
Mycelial Growth ◽  
Phytophthora Capsici ◽  
Dry Weight ◽  
Salinity Level ◽  
Growth Media ◽  
Chile Pepper ◽  
Zoospore Formation ◽  
Level Production ◽  
Pepper Plants

The response of chile pepper to salinity and infection by Phytophthora capsici was assessed under greenhouse conditions in plants susceptible or resistant to P. capsici. Additionally, the effect of salinity on mycelial growth and production of sporangia and zoospores by P. capsici was evaluated in the laboratory. Salinity treatments consisted of varying levels of electrical conductivity (from 1.8 to 14.4 dS/m) achieved by amending irrigation water or growth media with a mixture of sodium chloride and calcium chloride. In plants susceptible to P. capsici, disease severity increased by approximately 1.3 to 2.7-fold with increasing salinity level, whereas no such effect was observed in plants resistant to P. capsici. Mycelial dry weight increased by 8 to 16%, and radial growth of mycelium was augmented by 5 to 30% with increase in salinity level. Production of sporangia and zoospore formation were reduced by approximately 3 to 85 and 1 to 93%, respectively, under saline conditions. These results indicate that salinity may predispose susceptible chile pepper plants to infection by P. capsici.

scholarly journals Chile Pepper Sensitivity to Mustard Seed Meal Applied after Crop Emergence

HortScience ◽  
2021 ◽  
Vol 56 (2) ◽  
pp. 254-260
Author(s):  
Asmita Nagila ◽  
Brian J. Schutte ◽  
Soum Sanogo ◽  
Omololu John Idowu
Keyword(s):  
Field Study ◽  
Pest Management ◽  
Mycelial Growth ◽  
Soil Surface ◽  
Palmer Amaranth ◽  
Seed Meal ◽  
Mustard Seed ◽  
Chile Pepper ◽  
Greenhouse Study ◽  
Pepper Plants

When applied before crop emergence, soil amendments with mustard seed meal (MSM) control some weeds and soilborne pathogens. MSM applications after crop emergence (herein “postemergence applications”) might be useful components of agricultural pest management programs, but research on postemergence applications of MSM is limited. The overall objective of this investigation was to develop a method for postemergence application of MSM that does not cause irrecoverable injury or yield loss in chile pepper (Capsicum annuum). To accomplish this objective, we conducted a sequence of studies that evaluated different MSM rates and application methods in the greenhouse and field. For the greenhouse study, we measured chile plant photosynthetic and growth responses to MSM applied postemergence on the soil surface or incorporated into soil. For the field study, we determined chile pepper fruit yield responses to MSM applied postemergence using a technique based on the method developed in greenhouse, and we confirmed that the MSM rates used in our study (4400 kg·ha−1 and 2200 kg·ha−1) inhibited the emergence of the weed Palmer amaranth (Amaranthus palmeri) and the growth of the pathogen Phytophthora capsici, which are common problems in chile pepper production in New Mexico. Greenhouse study results indicated that MSM at 4400 kg·ha−1 spread on the soil surface caused irrecoverable injury to chile pepper plants; however, chile pepper plants were not permanently injured by the following three treatments: 1) MSM at 4400 kg·ha−1 incorporated into soil, 2) MSM at 2200 kg·ha−1 spread on the soil surface, and 3) MSM at 2200 kg·ha−1 incorporated into soil. For the field study, postemergence, soil-incorporated applications of MSM at 4400 kg·ha−1 suppressed emergence of Palmer amaranth by 89% and reduced mycelial growth of Phytophthora capsica by 96%. Soil-incorporated applications of MSM at 2200 kg·ha−1 suppressed emergence of Palmer amaranth by 41.5% and reduced mycelial growth of Phytophthora capsica by 71%. Postemergence soil-incorporated applications of MSM did not reduce chile pepper yield compared with the control. The results of this study indicated that MSM applied after crop emergence and incorporated into soil can be a component of pest management programs for chile pepper.

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 In Vitro Suppression of Soilborne Plant Pathogens by Coir

2009 ◽  
Vol 19 (1) ◽  
pp. 96-100 ◽  
Author(s):  
Naveen Hyder ◽  
James J. Sims ◽  
Stephen N. Wegulo
Keyword(s):  
Fusarium Solani ◽  
Mycelial Growth ◽  
Aspergillus Terreus ◽  
Plant Pathogens ◽  
Cocos Nucifera ◽  
Phytophthora Capsici ◽  
Potato Dextrose Agar ◽  
Soilborne Pathogens ◽  
Soilborne Plant Pathogens

Experiments conducted in vitro showed that coir [coconut (Cocos nucifera) mesocarp pith] suppressed growth of soilborne plant pathogens. Mycelial growth of Phytophthora capsici on potato dextrose agar (PDA) amended with an unsterilized coir suspension was strongly inhibited regardless of suspension concentration. Growth of P. capsici on PDA amended with a filter-sterilized coir suspension was uninhibited. Growth of Fusarium solani on water agar (WA) amended with unautoclaved coir was completely inhibited. Growth of F. solani on WA amended with autoclaved coir was uninhibited. Aspergillus terreus recovered from coir inhibited mycelial growth of various soilborne pathogens by up to 75%. The results from this study suggest that coir has the ability to suppress soilborne plant pathogens in vitro and this ability is largely due to microorganisms associated with the substrate.

scholarly journals Recovery of Verticillium dahliae from Tall Morningglory (Ipomoea purpurea) in New Mexico and its Pathogenicity on Chile Pepper

Plant Disease ◽  
2009 ◽  
Vol 93 (4) ◽  
pp. 428-428 ◽  
Author(s):  
S. Sanogo ◽  
B. F. Etarock ◽  
M. Clary
Keyword(s):  
New Mexico ◽  
Verticillium Wilt ◽  
Verticillium Dahliae ◽  
Common Disease ◽  
Infested Soil ◽  
Conidial Suspension ◽  
Chile Pepper ◽  
Ipomoea Purpurea ◽  
Vascular Discoloration ◽  
Pepper Plants

Verticillium wilt, caused by Verticillium dahliae, is a common disease of chile pepper (Capsicum annuum) in New Mexico. In August of 2007, wilted plants with vascular discoloration in the stem typical of infection by V. dahliae occurred in several fields in Luna County in southern New Mexico. In one field, Verticillium wilt incidence was between 60 and 70%. Approximately 30% of the field was infested with Physalis wrightii (Wrights groundcherry) and Anoda cristata (spurred anoda), and 60% of the field was infested with Ipomoea purpurea (tall morningglory). Except for vascular discoloration found in a few plants of Wrights groundcherry and spurred anoda, there were no other symptoms observed in the weeds present. Previously, Wrights groundcherry and spurred anoda were demonstrated as hosts to V. dahliae (2); however, to our knowledge, tall morningglory was not. A 5-cm segment was cut from the lower part of the stems and upper part of the tap roots of six tall morningglory plants and two chile pepper plants. The segments were washed, surface disinfested for 2 min in 0.5% sodium hypochlorite, and cut into pieces that were plated onto water agar. Mycelial colonies emerging from the pieces were transferred to either potato dextrose agar, prune extract agar, or Czapek-Dox agar medium. Putative V. dahliae isolates from tall morningglory and chile pepper plants were identified based on characteristic morphological features when cultured on prune extract medium (2,3). In addition, PCR of fungal DNA and sequencing the amplicons using primer pair ITS4/ITS6 showed a 99% homology with the sequence of the rDNA ITS of V. dahliae (1). Pathogenicity tests were conducted with two isolates of V. dahliae from tall morningglory and one from chile pepper. In the first of two methods, four pots were infested with conidia of each isolate (2 × 107 conidia per 500 cm3 of soilless mix) and planted (five seeds per pot, thinned to three seedlings) with chile pepper cv. AZ-20, which is susceptible to V. dahliae. Three noninfested pots served as the control. Pots were placed in a growth chamber at 26/20°C day/night temperature. In the second method, plants (cv. AZ-20) at the 6- to 8-leaf stage were inoculated in a greenhouse with V. dahliae by dispensing 5 ml of a conidial suspension (4 × 106 conidia/ml) into the root plug prior to transplanting. Four root plugs were inoculated per isolate and there were three noninoculated root plugs. Both experiments were repeated once. Isolates of V. dahliae recovered from tall morningglory and chile pepper were pathogenic on chile pepper. Leaf chlorosis, leaf drop, wilting, and vascular discoloration were observed within 8 weeks after sowing into infested soil or within 6 weeks after inoculation into the root plugs of transplants. No symptoms were observed on noninoculated plants. V. dahliae was reisolated from the stems of all symptomatic plants. To our knowledge, this is the first report to document the recovery of V. dahliae from tall morningglory and its pathogenicity on chile pepper. References: (1) P. V. Pramateftaki et al. J. Fungal Genet. Biol. 29:19, 2000. (2). S. Sanogo and M. Clary. Plant Dis. 87:450, 2003. (3) P. W. Talboys. Plant Pathol. 9:57, 1979.

Vegetable Seedling Diseases Associated with Earthworm Castings Contaminated with Phytophthora capsici and Pythium Attrantheridium

2012 ◽  
Vol 13 (1) ◽  
pp. 15 ◽  
Author(s):  
Bo Liu ◽  
Debbie Roos ◽  
Shawn Buttler ◽  
Brantlee Richter ◽  
Frank J. Louws
Keyword(s):  
North Carolina ◽  
Plant Growth ◽  
Plant Material ◽  
Phytophthora Capsici ◽  
Growth Media ◽  
Soilborne Pathogens ◽  
Pythium Species ◽  
Organic Farms ◽  
Beneficial Effects ◽  
Vegetable Seedlings

Earthworms and worm castings have been recommended for their beneficial effects in increasing yields and suppressing soilborne diseases. However, in a few cases, earthworm castings have been shown to harbor soilborne pathogens. The research documents that earthworm castings used as an amendment in soilless potting mixes at several organic farms in North Carolina were contaminated with Phytophthora capsici and several Pythium species. Phytophthora capsici and P. attrantheridium were subsequently isolated from rotted roots of vegetable seedlings grown in the potting mix. Commercial producers of earthworm castings should only use clean plant material to maintain earthworms and earthworm castings should be ascertained as pathogen-free before incorporation into plant growth media. Accepted for publication 30 January 2012. Published 21 April 2012.

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 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.

Development and quantitative measurement of microsclerotia of Verticillium dahliae

1972 ◽  
Vol 50 (11) ◽  
pp. 2097-2102 ◽  
Author(s):  
R. Hall ◽  
H. Ly
Keyword(s):  
Verticillium Dahliae ◽  
Mycelial Growth ◽  
Quantitative Measurement ◽  
Dry Weight ◽  
Pure Cultures ◽  
Carbon Nitrogen Ratio ◽  
Low Glucose ◽  
Nitrogen Ratio ◽  
Total Dry Weight ◽  
Hyaline Material

The development of microsclerotia of Verticillium dahliae from a few swollen hyaline cells on a hypha to a multicellular, pigmented "mature" structure is described and illustrated. A method for quantitatively estimating the amount of pigmented microsclerotial material in pure cultures was developed to study quantitative relations between mycelial growth and production of microsclerotial material in media containing different concentrations of glucose. At low glucose concentrations (0.6 to 10 mg/ml) microsclerotial material continued to increase after total dry weight of the cultures had reached a maximum, suggesting conversion of hyaline to pigmented material. At high glucose concentrations (20 to 60 mg/ml) the patterns of increase in total dry weight, microsclerotial material, and hyaline material were similar over a 4-week incubation period. Maximum production of both pigmented and hyaline materials occurred at a glucose concentration of 30 mg/ml (carbon/nitrogen ratio of 50/1).

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