scholarly journals Bean Rust Control under Field Conditions with Systemic and Contact Fungicides.

1969 ◽  
Vol 70 (1) ◽  
pp. 45-55
Author(s):  
Pedro L. Meléndez ◽  
Rocío Rodríguez ◽  
Linda Wessel-Beaver
Keyword(s):  
Puerto Rico ◽  
Disease Incidence ◽  
Genetic Resistance ◽  
Field Conditions ◽  
Uromyces Appendiculatus ◽  
Bean Rust ◽  
Disease Symptoms ◽  
Systemic Fungicides

Bean rust (Uromyces appendiculatus) was generally controlled with both contact and systemic fungicides on three cultivars (Blanca del País, Bountiful and Naranjito) tested at two locations in Puerto Rico. However, effectiveness varied with rate, cultivar, location and disease level. On cultivars in Lajas, contact fungicides chlorothalonil and mancozeb were more effective in reducing disease symptoms and in increasing yields than the systemic fungicides oxycarboxin and triforine. There were fewer differences between fungicides in Isabela, where disease incidence was lower, but contact fungicides again were generally more effective. Mancozeb was the most effective fungicide, reducing disease symptoms and increasing yields. Certain fungicides combined with genetic resistance should be effective in increasing bean yields.

scholarly journals Assessing Genetic Resistance in Wheat to Black Point Caused by Six Fungal Species in the Yellow and Huai Wheat Area of China

Plant Disease ◽  
2020 ◽  
Vol 104 (12) ◽  
pp. 3131-3134
Author(s):  
Qiaoyun Li ◽  
Mengyu Li ◽  
Yumei Jiang ◽  
Siyu Wang ◽  
Kaige Xu ◽  
...  
Keyword(s):  
Disease Incidence ◽  
Genetic Resistance ◽  
Bipolaris Sorokiniana ◽  
Triticum Aestivum L ◽  
Fungal Species ◽  
Field Conditions ◽  
Sources Of Resistance ◽  
Black Point ◽  
Environmentally Sustainable ◽  
Resistant Cultivars

The most effective and environmentally sustainable method for controlling black point disease of wheat (Triticum aestivum L.) is to plant resistant cultivars. To identify sources of resistance to black point, 165 selected cultivars/lines were inoculated with isolates of six fungal species (Bipolaris sorokiniana, Alternaria alternata, Fusarium equiseti, Exserohilum rostratum, Epicoccum sorghinum, and Curvularia spicifera) known to cause black point in wheat using spore suspensions under controlled field conditions in 2016 and 2017. Inoculation of the isolates significantly increased the incidence of black point in the cultivars/lines compared with those grown under natural field conditions (NFC). The disease incidence of plants inoculated with B. sorokiniana and E. rostratum was 15.5% and 18.8% in 2016, and 20.4% and 23.0% in 2017, whereas those under NFC were 5.7% (2016) and 1.5% (2017), respectively. Furthermore, disease symptoms varied with pathogen. Among the 165 cultivars/lines tested, 3.6%, 50.9%, 60.0%, 1.8%, 47.3%, and 58.8% were resistant to B. sorokiniana, A. alternata, F. equiseti, E. rostratum, E. sorghinum, and C. spicifera, respectively. In addition, we identified one line (‘SN530070’) resistant to black point caused by all six pathogens. This is the first study to assess resistance to wheat black point caused by six fungal species under controlled conditions. The black point-resistant cultivars/lines could be useful in breeding and also in research on the mechanisms of resistance to black point.

scholarly journals Fungicide evaluation for control of powdery mildew, Leveillula taurica (Lev.) Arn., of peppers in Puerto Rico

1969 ◽  
Vol 75 (2) ◽  
pp. 119-123
Author(s):  
José A. Negrón ◽  
Rocío Rodríguez ◽  
Lucas Avilés
Keyword(s):  
Puerto Rico ◽  
Powdery Mildew ◽  
Capsicum Annuum ◽  
Disease Incidence ◽  
Causal Agent ◽  
Field Conditions ◽  
Copper Hydroxide ◽  
Leveillula Taurica

The effectiveness of benomyl, chlorothalonil, copper hydroxide, dinocap, sulfur and triadimefon for the control of the fungus Leveillula taurica, causal agent of the powdery mildew of peppers (Capsicum annuum), was evaluated under field conditions. Results from two experiments indicate that weekly applications of benomyl and triadimefon reduced disease incidence and increased pepper yield. In the first experiment, plots treated with triadimefon (0.35 L/ha) and benomyl (0.55 kg/ha) produced 20.2 and 17.2 kg fruit/plot, respectively, whereas the nontreated plots yielded 13,9 kg/plot. A similar trend but with higher yields was obtained in the second experiment. Treatments with triadimefon (0.70 L/ha) and benomyl (0.55 kg/ha) produced 41.0 and 41.3 kg of fruit/plot, respectively, as compared with the control treatments which yielded 29.0 kg/plot.

First Report of Bean Rust Caused by Uromyces appendiculatus Race 19-63 in Puerto Rico

2009 ◽  
Vol 10 (1) ◽  
pp. 46 ◽  
Author(s):  
Byron Vega ◽  
James S. Beaver ◽  
Consuelo Estévez de Jensen ◽  
James R. Steadman
Keyword(s):  
Puerto Rico ◽  
Phaseolus Vulgaris ◽  
Common Bean ◽  
Western Hemisphere ◽  
Uromyces Appendiculatus ◽  
Bean Rust ◽  
Phaseolus Vulgaris L ◽  
First Report ◽  
New Race ◽  
Important Disease

Bean rust caused by Uromyces appendiculatus (Pers.) Unger is an important disease in common bean (Phaseolus vulgaris L.) worldwide. To our knowledge this is the first report of a new race of U. appendiculatus (19-63) in Puerto Rico and in the western hemisphere. Accepted for publication 4 February 2009. Published 25 March 2009.

scholarly journals Field Evaluation of Tomato Cultivars for Tolerance to Tomato Chlorotic Spot Tospovirus

2019 ◽  
Vol 20 (2) ◽  
pp. 77-82 ◽  
Author(s):  
Shouan Zhang ◽  
Xiaohui Fan ◽  
Yuqing Fu ◽  
Qingren Wang ◽  
Eugene McAvoy ◽  
...  
Keyword(s):  
Frankliniella Occidentalis ◽  
Disease Incidence ◽  
Total Yield ◽  
Genetic Resistance ◽  
Field Evaluation ◽  
South Florida ◽  
Fruit Yield ◽  
Field Conditions ◽  
Chlorotic Spot ◽  
Tomato Cultivars

Fourteen tomato cultivars resistant to tomato spotted wilt tospovirus (TSWV) were evaluated for their tolerance against tomato chlorotic spot tospovirus (TCSV) under field conditions during the 2014–2015 and 2015–2016 growing seasons in Homestead, FL. All TSWV-resistant tomato cultivars had significantly (P < 0.05) lower disease incidence of TCSV, compared with the commercial standard cultivars ‘FL 47’ or ‘Sanibel’, exhibiting intermediate to high levels of tolerance to TCSV. There was no significant effect of tomato genotype on the thrips vectors, western flower thrips (Frankliniella occidentalis) and common blossom thrips (F. schultzei). All tested tomato cultivars had equivalent or greater yields of total marketable fruit compared with the standard cultivar Sanibel. Particularly, in the third trial with disease incidence of 25% on Sanibel, ‘BHN 1064’ had significantly greater total yield and yields of extra-large and large fruit compared with Sanibel. ‘SV 7631TD’ and ‘Brickyard’ had significantly greater extra-large fruit yield and medium fruit yield, respectively, compared with Sanibel. Results from this study show that TSWV-resistant tomato cultivars were tolerant to TCSV under field conditions of south Florida, indicating that the use of genetic resistance in commercial tomato cultivars is an effective strategy to manage TCSV.

scholarly journals Fungicidal Efficacy of Drying Plant Oils in Green Beans against Bean Rust (Uromyces appendiculatus)

Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 143
Author(s):  
Vera Breiing ◽  
Jennifer Hillmer ◽  
Christina Schmidt ◽  
Michael Petry ◽  
Brigitte Behrends ◽  
...  
Keyword(s):  
Unsaturated Fatty Acids ◽  
Plant Protection ◽  
Linseed Oil ◽  
Uromyces Appendiculatus ◽  
Plant Oils ◽  
Bean Rust ◽  
Green Beans ◽  
Plant Oil ◽  
Water Emulsion ◽  
Tung Oil

As biorationals, plant oils offer numerous advantages such as being natural products, with low ecotoxicological side effects, and high biodegradability. In particular, drying glyceride plant oils, which are rich in unsaturated fatty acids, might be promising candidates for a more sustainable approach in the discussion about plant protection and the environment. Based on this, we tested the protective and curative efficacy of an oil-in-water-emulsion preparation using drying plant oils (linseed oil, tung oil) and a semi-drying plant oil (rapeseed oil) separately and in different mixtures. Plant oils were tested in greenhouse experiments (in vivo) on green beans (Phaseolus vulgaris L.) against bean rust (Uromyces appendiculatus). We observed that a 2% oil concentration showed no or very low phytotoxic effects on green beans. Both tested drying oils showed a protective control ranging from 53–100% for linseed oil and 32–100% for tung oil. Longer time intervals of 6 days before inoculation (6dbi) were less effective than shorter intervals of 2dbi. Curative efficacies were lower with a maximum of 51% for both oils when applied 4 days past inoculation (4dpi) with the fungus. Furthermore, the results showed no systemic effects. These results underline the potential of drying plant oils as biorationals in sustainable plant protection strategies.

scholarly journals Isolates of Uromyces appendiculatus with Specific Virulence to Landraces of Phaseolus vulgaris of Andean Origin

Plant Disease ◽  
1999 ◽  
Vol 83 (2) ◽  
pp. 108-113 ◽  
Author(s):  
Craig M. Sandlin ◽  
James R. Steadman ◽  
Carlos M. Araya ◽  
Dermot P. Coyne
Keyword(s):  
Phaseolus Vulgaris ◽  
Rapd Analysis ◽  
Random Amplified Polymorphic Dna ◽  
Rust Fungus ◽  
Distinct Group ◽  
Uromyces Appendiculatus ◽  
Bean Rust ◽  
Banding Patterns ◽  
Highly Virulent ◽  
Specific Virulence

Five isolates of the bean rust fungus Uromyces appendiculatus were shown to be specifically virulent on bean genotypes of Andean origin. This specificity was demonstrated by the virulence of five pairs of isolates on a differential set of 30 Phaseolus vulgaris landraces. Each isolate pair was from a different country in the Americas and consisted of one Andean-specific isolate and one nonspecific isolate. Of the differential P. vulgaris landraces, 15 were of Middle American origin and 15 were of Andean origin. The Andean-specific rust isolates were highly virulent on Andean landraces but not on landraces of Middle American origin. Rust isolates with virulence to Middle American landraces were also generally virulent on Andean material; no truly Middle American-specific isolates were found. Random amplified polymorphic DNA (RAPD) analysis of the rust isolates also distinguished the two groups. Four of the Andean-specific rust isolates formed a distinct group compared to four of the nonspecific isolates. Two of the isolates, one from each of the two virulence groups, had intermediate RAPD banding patterns, suggesting that plasmagomy but not karyogamy occurred between isolates of the two groups.

Meliola mangiferae. [Descriptions of Fungi and Bacteria].

1998 ◽  
Author(s):  
M. Rodríguez
Keyword(s):  
Puerto Rico ◽  
Costa Rica ◽  
Geographical Distribution ◽  
Mangifera Indica ◽  
British Guiana ◽  
Disease Symptoms ◽  
The Family

Abstract A description is provided for Meliola mangiferae. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. DISEASE: Meliola mangiferae, as with the family Meliolaceae in general, is found on living leaves parasitizing the epidermis and sometimes deeper tissues, but without production of obvious disease symptoms. HOSTS: Mangifera indica, M. rigida and Mangifera sp. (Hansford, 1961). GEOGRAPHICAL DISTRIBUTION: Brazil, British Guiana, Costa Rica, Cuba, India, Indonesia (Java), Jamaica, Malaysia, Panama, Philippines, Puerto Rico, Surinam, Trinidad & Tobago, Venezuela. Meliola mangiferae is found in practically all areas of mango cultivation, with the exception of Africa and Australia (Hansford, 1961). TRANSMISSION: By air-borne ascospores.

scholarly journals Screening Brassica Cultivars for Resistance to Western Oregon Clubroot Pathotypes

2017 ◽  
Vol 27 (4) ◽  
pp. 510-516
Author(s):  
Aaron Heinrich ◽  
Shinji Kawai ◽  
Jim Myers
Keyword(s):  
Plasmodiophora Brassicae ◽  
Disease Incidence ◽  
Genetic Resistance ◽  
Crop Loss ◽  
Soilborne Pathogen ◽  
Host Reaction ◽  
Brussels Sprouts ◽  
Pak Choi ◽  
Susceptible Control ◽  
Brassicaceae Family

Growing resistant cultivars from the Brassicaceae family (brassicas) is an effective strategy to minimize crop loss caused by the soilborne pathogen Plasmodiophora brassicae (clubroot). However, there are many clubroot pathotypes, and genetic resistance to clubroot may be pathotype-specific. To determine which pathotypes are present in western Oregon, diseased roots were collected from five farms and identified by the European clubroot differential (ECD) set. To assess resistance to the identified pathotypes, 21 vegetable cultivars from nine crops with purported resistance to clubroot were evaluated for disease incidence and severity in field and greenhouse studies. The crops evaluated included broccoli (Brassica oleracea var. italica), cauliflower (B. oleracea var. botrytis), brussels sprouts (B. oleracea var. gemmifera), cabbage (B. oleracea var. capitata), napa cabbage (Brassica rapa var. pekinensis), pak choi (B. rapa var. chinensis), kohlrabi (B. oleracea var. gongylodes), turnip (B. rapa var. rapa), and rutabaga (Brassica napus var. napobrassica). ECD host reaction showed similar virulence among clubroot collections, and all field isolates had the same ECD pathotype designation, 16/02/30. Compared with a crop-specific susceptible control, 17 of 21 cultivars had some resistance to clubroot, and of those, 15 were highly resistant (≤15% incidence with low disease severity). This research demonstrated that western Oregon farmers have several commercially available cultivars with resistance to the dominant pathotyope in the region. However, each farmer must evaluate the suitability of these cultivars to meet consumer and industry requirements.

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