Seed, plant, and soil treatment with selected commercial Bacillus-based and Streptomyces-based biofungicides and chemical fungicides and development of Phytophthora blight on chile pepper

Author(s):  
Soum Sanogo ◽  
Phillip Lujan
HortScience ◽  
2010 ◽  
Vol 45 (10) ◽  
pp. 1563-1566 ◽  
Author(s):  
Ariadna Monroy-Barbosa ◽  
Paul W. Bosland

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.


2014 ◽  
Vol 15 (4) ◽  
pp. 166-171 ◽  
Author(s):  
Michael E. Matheron ◽  
Martin Porchas

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.


Plant Disease ◽  
2006 ◽  
Vol 90 (3) ◽  
pp. 291-296 ◽  
Author(s):  
S. Sanogo ◽  
J. Carpenter

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.


2020 ◽  
Vol 14 (1) ◽  
pp. 15-20
Author(s):  
Ram Devi Timila ◽  
Shrinkhala Manandhar

Phytophthora blight (PB) caused by Phytophthora capsici Leonian is an economically important disease of pepper in Nepal. Experiments were conducted in epiphytotic conditions at Luvu, Lalitpur where severe outbreak of PB used to occur. The experiment was designed in randomized complete block with three replications. Three isolates of Trichoderma harzianum viz, T. harzianum (T22), T. harzianum (T69), and T. harzianum and one isolate of T. asperellum, were tested for their efficacy under the field conditions compared to chemical fungicides, copper oxychloride and fluazinam for two years, 2012 and 2013. In the first year experiment, the effect of all three isolates of T. harzianum was significantly different from the control. T. harzianum (T69), the local isolate was found better in reducing PB incidence and severity by 46% and 27% respectively during 2012. Similarly, in 2013 PB incidence and severity were reduced by 36% and 42% respectively and yield increased by 57% over control. However the chemical fungicides, fluazinam was the best treatment in reducing PB severity with increased yield by 70% followed by copper oxychloride that increased yield by 62% over control during 2013. There was no significant difference in efficacy of T69 and tested chemical fungicides. Hence, the use of Trichoderma harzianum (T69) could be one of the environmentally sound tools for the integrated management of Phytophthora blight.


HortScience ◽  
2008 ◽  
Vol 43 (6) ◽  
pp. 1846-1851 ◽  
Author(s):  
Mohammed B. Tahboub ◽  
Soumaila Sanogo ◽  
Paul W. Bosland ◽  
Leigh Murray

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.


Plant Disease ◽  
2000 ◽  
Vol 84 (9) ◽  
pp. 1038-1043 ◽  
Author(s):  
M. E. Matheron ◽  
M. Porchas

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.


Author(s):  
Phillip A Lujan ◽  
Srijana Dura ◽  
Ivette Guzman ◽  
Mary Grace ◽  
Mary Lila ◽  
...  

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.


2015 ◽  
Vol 16 (4) ◽  
pp. 218-222 ◽  
Author(s):  
Michael E. Matheron ◽  
Martin Porchas

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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