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.

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 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.

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.

Yield losses caused by Colletotrichum gloeosporioides in three species of Stylosanthes

1987 ◽  
Vol 27 (1) ◽  
pp. 67 ◽  
Author(s):  
RD Davis ◽  
JAG Irwin ◽  
RK Shepherd ◽  
DF Cameron
Keyword(s):  
Dry Matter ◽  
Colletotrichum Gloeosporioides ◽  
Disease Incidence ◽  
Weather Conditions ◽  
Yield Losses ◽  
Initial Infection ◽  
Infected Control ◽  
Wet Weather ◽  
Seed Yields ◽  
Disease Free

Yield losses from the fungal disease anthracnose, caused by Colletotrichum gloeospovioides, were estimated for 3 species of Stylosanthes grown in northern Queensland. Naturally infected control plots of S. scabra cv. Fitzroy, S. hamata cv. Verano and S. guianensis cv. Graham were compared with plots protected by 3 benomyl spray treatments designed to restrict anthracnose development to 0, 25 and 50% of the level sustained in the unsprayed control plots. Following initial infection in early February 1984, disease incidence and severity in Fitzroy and Verano reached a maximum during early March. This rapid build up of disease was associated with a period of sustained wet weather. Graham only became infected much later in the season as the plants matured, and sustained severe anthracnose lesions on both leaves and stems even though weather conditions appeared unsuitable for an epidemic. Yield losses were severe in all 3 cultivars. Average dry matter yields of the unsprayed controls were only 21.6, 66.7, and 53.5% respectively of the yields of the disease free plots for Fitzroy, Verano and Graham. Corresponding seed yields were 15.6, 48.9 and 42.5% respectively. Highly significant negative correlations were found between dry matter and seed yields of the 3 species and the incidence and severity of anthracnose disease.

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.

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.

Fitness and competitive ability of field isolates of Phytophthora capsici resistant or sensitive to fluopicolide

Plant Disease ◽  
2020 ◽  
Author(s):  
Li Wang ◽  
Pingsheng Ji
Keyword(s):  
Mycelial Growth ◽  
Competitive Ability ◽  
Phytophthora Capsici ◽  
Bell Pepper ◽  
Vegetable Production ◽  
Vegetable Crops ◽  
Phytophthora Blight ◽  
Field Isolates ◽  
Significant Difference ◽  
The World

Phytophthora blight, caused by Phytophthora capsici, is one of the most destructive diseases in the production of solanaceous and cucurbitaceous vegetable crops. Fluopicolide has been used to control the disease; however, reduced efficacy of the fungicide was observed in Georgia. P. capsici isolates were collected from commercial vegetable fields in Georgia in 2018 and 2019 to determine sensitivity to fluopicolide, which were phenotyped to have 43.1% of the isolates as resistant. The fitness of resistant (R) and sensitive (S) isolates was assessed through mycelial growth and sporulation assays exposed to the fungicide (0 or 50 µg/ml). Fluopicolide did not reduce mycelial growth, sporangial production and zoospore germination of the resistant isolates. In the absence of fluopicolide, there was no significant difference between the R and S isolates in sporangial production, but mycelial growth and zoospore germination of the R isolates was greater than the S isolates (P = 0.01 and 0.001, respectively). The R isolates had similar ability as S isolates to induce disease on ‘Aristotle’ bell pepper, and most of the R and S isolates caused the same level of disease on ‘Paladin’. Inoculating squash fruit using different R:S ratios and recovering R and S isolates after 5 cycles of inoculation resulted in similar trends in changes of R vs. S isolates ratios. Overall it appeared that fitness and competitive ability of the R isolates were not reduced compared to the S isolates. This is the first report of the occurrence of field isolates of P. capsici resistant to fluopicolide in the world. The results have significant implications in providing guidance for growers to avoid or limit use of this fungicide in vegetable production.

scholarly journals Design, Development, and Performance Evaluation of a Power-Operated Jute Fiber Extraction Machine

2021 ◽  
Vol 3 (2) ◽  
pp. 403-422
Author(s):  
Md. Rejaul Karim ◽  
Muhammad Arshadul Hoque ◽  
Alamgir Chawdhury ◽  
Faruk-Ul-Islam ◽  
Sharif Ahmed ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
Production Cost ◽  
Cost Effective ◽  
Labor Cost ◽  
Jute Fiber ◽  
Design Development ◽  
Regional Office ◽  
Practical Action ◽  
Traditional System ◽  
Fiber Extraction

Jute is the golden fiber of Bangladesh, but its production is declining due to the involvement of higher production and processing costs, where a major portion of the cost is needed for fiber extraction. Labor unavailability and increasing labor cost have led to higher jute fiber production cost. To address these issues, this study looks at the development of a power-operated and cost-effective fiber extraction machine aiming at reducing the production cost. The study was conducted at the Rangpur regional office premises of Practical Action in Bangladesh, and the developed machine was branded as “Aashkol”, which had the following major parts: a feeding tray, a primary extraction roller, a secondary extraction roller, grabbing rollers, fiber collection stand, base frame, protection cover, and a spring-loaded tray under the primary extraction roller. The Aashkol can extract green ribbon from the jute stem, but jute sticks were broken down into smaller pieces (3–6 cm). The performance evaluation of the machine was conducted using different types of jute (Deshi, Kenaf, and Tossa) and compared with another jute extraction machine (KP model, introduced by Karupannya Rangpur Ltd.). The Aashkol-based extraction and improved retting systems were also evaluated and compared with traditional jute extraction systems. The jute stem input capacity (4.99 t h−1) of the Aashkol was 47.6% higher than the KP model (3.38 t h−1). Compared with the traditional system, across jute types, the Aashkol produced a 9% higher fiber yield and saved 46% retting time. Overall, the Aashkol reduced 90% of the labor requirement and saved 11.6 USD t−1 in jute fiber extraction and retting than the traditional method.

Comparative observations on the pest and disease incidence and yield losses of Japonica, Indica and Japonica × Indica rices

1991 ◽  
Vol 37 (3) ◽  
pp. 290-295
Author(s):  
S. Bleih ◽  
S. B. De Sagun ◽  
R. Ramachandran
Keyword(s):  
Disease Incidence ◽  
Yield Losses

scholarly journals Fitness of Isolates of Phytophthora capsici Resistant to Mefenoxam from Squash and Pepper Fields in North Carolina

Plant Disease ◽  
2008 ◽  
Vol 92 (10) ◽  
pp. 1439-1443 ◽  
Author(s):  
Adalberto C. Café-Filho ◽  
Jean Beagle Ristaino
Keyword(s):  
North Carolina ◽  
Phytophthora Capsici ◽  
Colony Growth ◽  
Relative Fitness ◽  
In Planta ◽  
Phytophthora Blight ◽  
In Vivo Experiments ◽  
First Time

Despite the wide adoption of mefenoxam (Ridomil Gold EC) for vegetables in North Carolina, the incidence of Phytophthora blight on pepper (Capsicum annuum) and squash (Cucurbita pepo) is high. Seventy-five isolates of Phytophthora capsici were collected in five pepper and one squash field in order to assess mefenoxam sensitivity. The relative fitness of resistant and sensitive isolates was contrasted in vitro by their respective rates of colony growth and their ability to produce sporangia in unamended V8 juice agar medium. In in vivo experiments, the aggressiveness of isolates on pepper was evaluated. The frequency of resistant isolates in North Carolina populations was 63%, considerably higher than resistance levels in areas where mefenoxam is not widely adopted. Resistant isolates grew on amended media at rates >80 to 90% and >100% of the nonamended control at 100 μg ml-1 and 5 μg ml-1, respectively. Sensitive isolates did not growth at 5 or 100 μg ml-1. All isolates from three fields, including two pepper and a squash field, were resistant to mefenoxam. Populations from other fields were composed of either mixes of sensitive and resistant isolates or only sensitive isolates. Response to mefenoxam remained stable during the course of in vitro and in planta experiments. Occurrence of a mefenoxam-resistant population of P. capsici on squash is reported here for the first time in North Carolina. When measured by rate of colony growth, sporulation in vitro, or aggressiveness in planta, fitness of resistant isolates was not reduced. Mefenoxam-resistant isolates from squash were as aggressive on pepper as sensitive or resistant pepper isolates. These results suggest that mefenoxam-resistant populations of P. capsici are as virulent and fit as sensitive populations.

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