P. Srivastava, D. J. Mailhot, B. Leite, J. J. Marois, and D.L. Wright. University of Florida, 155 Research Rd, Quincy, FL 32351
Hardlock is a severe disease of cotton in the Coastal Plains of the southeastern United States. It is assumed to be associated with high nitrogen, high plant density, high temperature and humidity, insect damage and seed rot. We have found that application of fungicide on cotton flower reduces disease. Flower inoculation studies have indicated that hardlock is caused by the fungal pathogen Fusarium verticillioides, also known as F. moniliforme. We have been investigating the actual pattern of colonization that takes place from the flower stigma to the flower ovary and to the seed. Artificial inoculations of flowers with a green fluorescent protein tagged Fusarium verticillioides isolate was carried out in greenhouse. The results showed that stigma, style and seeds at 20, 40 days after flowering, and open bolls, are easily colonized by F. verticillioides. This study allowed us to track the pathogen F. verticilloides progress through the boll maturation period and the interference of hyphae with fiber development.
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