&
MANAGEMENT IDENTIFICATION OF
Pumpkin Diseases
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Richard Latin and Karen Rane Department of Botany and Plant Pathology
Disease Page Sclerotinia Rot 4 Phytophthora Blight 5 Bacterial Fruit Spot 6 Powdery Mildew 7 Downy Mildew 8 Black Rot 9 Microdochium Blight 10 Fusarium Crown & Fruit Rots 11 Bacterial Wilt 12 Virus Diseases 13
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ITmay be difficult to imagine,
but we receive more
requests for information on pumpkin diseases and pumpkin disease control than on any other vegetable crop. Some of the requests arrive during the winter, when folks have had time to reflect on the previous seasons problems and are anxious to avoid similar problems during the next growing season. Unfortunately, most of the calls occur in August and September and are prompted by the sudden appearance of collapsed canopies or rotting fruit. Although some disease outbreaks are unforeseen, even by the keenest growers, most serious epidemics can be avoided by knowing which infectious diseases threaten the crop, recognizing their symptoms, and understanding how they spread and survive. This publication is designed to provide such information on the nature of several infectious pumpkin diseases.
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Sclerotinia Rot
The Sclerotinia fungus affects a wide variety of crop plants. Many vegetables including tomatoes, beans, and carrots, as well as cucurbits, are susceptible. The pathogen produces resilient structures, called sclerotia, that survive in our soils indefinitely. Therefore, once an outbreak occurs in a field, the potential for future outbreaks will remain high. Sclerotinia rot is a cool season disease, hence its appearance on pumpkins in years when summer temperatures are below normal. The most obvious symptoms of Sclerotinia rot occur on pumpkin vines (stems) and fruit. During periods of cool temperature and high relative humidity, a white, cottony mold develops around watersoaked infection sites (Figures 1 and 2). Solid, black sclerotia (see arrows) that are about the size of a watermelon seed are produced among the moldy growth.
FIGURE 1
FIGURE 2
Disease Characteristics
Pathogen spread:
Disease Management
Cultural control: Chemical control:
...
BP-17