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Occurrence and Control of Microdochium Blight in Ohio Pumpkin Fields

Wutz, Laura Ann
http://rave.ohiolink.edu/etdc/view?acc_num=osu1394809233

Abstract Details

2003, Master of Arts, Ohio State University, Plant Pathology.
Ohio pumpkin growers have reported increasing occurrence of Microdochium Blight caused by Plectosporium tabacinum. This fungal pathogen affects a wide variety of species from various countries, but in the United States it has been found mainly on cucurbits. Since the initial report of the disease in Louisiana in 1981, it has continued to be reported in areas of the Eastern United States. Microdochium Blight forms unsightly lesions on pumpkin fruit and kills the plant prematurely. Pumpkins are grown on 5,000-7,000 acres of Ohio farmland. A disease such as Microdochium Blight can cause severe economic loss to pumpkin growers. Commercial pumpkin (Cucurbita pepo) growers in OH with fields infested with P. tabacinum were interviewed. Information on variety, planting date, soil type, occurrence of weeds and crop rotation was gathered. Silty-loam soil and extended periods of humidity favored disease development. None of the varieties grown had economically useful genetic resistance to P. tabacinum. Pumpkin plots were established in 2001 and 2002 in soil naturally infested with P. tabacinum. Plot treatments consisted of bare soil, bare soil+Maneb, cattle-manure based vermicompost, cattle-manure based vermicompost+Maneb, wheat straw, and wheat straw+Maneb. In the 2001 field trials, symptoms of Microdochium Blight were apparent before scheduled fungicide treatments were applied. In the 2002 field plots flooded field conditions early in the season delayed planting until early July and early season sprays could not be applied. Under these conditions in 2001 and 2002, no fungicide treatment had significant effects on development of Microdochium Blight. Neither mulch treatment of cattle-manure based vermicompost or wheat straw had a significant effect on development of Microdochium Blight in either year. Data from 2001 was influenced by heavy damage caused to plants in straw mulch treatments by cucumber beetles. Control of P. tabacinum with preventative sprays of Bravo, Dithane, Flint, Kocide, Kocide+Bravo, Microthiol, Quadris and Topsin M were tested in the greenhouse. Pumpkins (Cucurbita pepo) 'Pro-Gold 500' were inoculated with P. tabacinum following application of sprays. Quadris and Flint gave significantly better control than the other treatments of the first rating 7 days following inoculation with average scores. No more than 6% of the total surface area of the plant was covered with Microdochium Blight lesions. Curative properties were tested with a subset of fungicides from the first trial. Bravo, Dithane, Flint and Quadris were applied at 0, 24, 48 and 72 hr after inoculation. As expected from results of the preventative greenhouse trials, Bravo and Dithane did not show curative effects. Quadris began losing fungicidal effect in the set of plants that were sprayed 24 hr after inoculation and Microdochium Blight lesions began developing on plants. Flint began losing effect in the set of plants that were sprayed 48 hr after plants were inoculated.
Richard M. Riedel (Advisor)
Landon H. Rhodes (Committee Member)
Mark A. Bennett (Committee Member)
66 p.
Plant Pathology

Recommended Citations

Citations

  • Wutz, L. A. (2003). Occurrence and Control of Microdochium Blight in Ohio Pumpkin Fields [Master's thesis, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1394809233

    APA Style (7th edition)

  • Wutz, Laura. Occurrence and Control of Microdochium Blight in Ohio Pumpkin Fields . 2003. Ohio State University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1394809233.

    MLA Style (8th edition)

  • Wutz, Laura. "Occurrence and Control of Microdochium Blight in Ohio Pumpkin Fields ." Master's thesis, Ohio State University, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=osu1394809233

    Chicago Manual of Style (17th edition)

osu1394809233
261
© 2003, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.