Gaertneriomyces species as a potential biological control agent of sorghum downy mildew /
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| Other Authors: | , |
| Format: | Thesis Book |
| Language: | English |
| Published: |
1991.
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| Subjects: | |
| Online Access: | Link to OAKTrust copy |
| Abstract: | Gaertneriomyces sp. was evaluated in greenhouse and field trials for its efficacy as a biological control agent of systemic sorghum downy mildew infection from soilbome oospores. Addition of chytrid reduced systemic infection by as much as 100% in greenhouse trials and by up to 50% or more in field trials. The amount of disease reduction in the field was positively correlated with the levels of chytrid incorporated. Irrigation improved the efficacy of the chytrid by as much as 20 percent. To determine the best way of applying the chytrid in the soil, banding, i.e. application of chytrid inoculum in oospore infested soil without mixing, was compared with incorporation, i.e. application and thorough mixing of chytrid inoculum in oospore infested soil. Incorporation was clearly the best method of application in all locations, resulting in the lowest incidence of disease. A comparative study of various times of chytrid application in the soil before planting the test crop showed that the longer the chytrid remained in the soil, the better the control even though this was not always significant. The chytrid could be retrieved from the soil up to 1 yr. after application. Field and electron microscope studies showed that the mechanism of biological control is by hyperparasitism manifested by lysis of the oospore walls. Using the ultrastructure of the zoospore, morphology, nutrition and development, the chytrid was identified as Gaenneriomyces semiglobiferum. |
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| Item Description: | Typescript (photocopy). Vita. "Major subject: Plant Pathology." |
| Physical Description: | xii, 100 leaves : illustrations ; 29 cm |
| Bibliography: | Includes bibliographical references. |