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Abstract

Nine Fusarium species, i.e. fusarioides, moniliforme, subglutinans, oxysporum, poae, sambucinum, semitectum, solani and sporotrichioides were isolated. Since F. fusarioides and F. sporotrichioides recorded as new additional pathogens to cotton plants. While F. solani expressed the highest disease severity (59%) and F. fusarioides gave the least disease severity (47.75%). Cotton Giza 87 cv. showed the least disease severity (40.4) and Giza 90 existed the most susceptible one (54.5% disease severity). Frequency of Fusarium species associated with cotton seeds, seedlings or plants was varied with sampling date, location, cotton cultivars and previous crops. Since the least frequency was obtained in April 2000 (35.58%), while the highest frequency (69.2%) was given by June 2000. Previous crop broad bean exhibited higher frequency than clover plants. Seeds of cotton Cultivar Giza 89 gave the highest frequency (12%) while cv. Giza 85 revealed the least frequency (2%). Fusarium species were infected cowpea, roselle and okra plants. Roselle plants were the most susceptible (gave 36.7% disease severity) while okra plants were the least susceptible (expressed 24.75% disease severity). Negative correlation was pronounced between plant age and infection with Fusarium species where 30 days old plants showed resistance against all tested fusaria (showed 4.4% disease severity) as compared to infection planting time. F. moniliforme and F. semitectum have ability to infect all cotton organs tested. F. poae infected cotyledons, flowers and bolls. Only cotyledons and followers were infected by F. fusarioides. Otherwise Fusarium species had no ability to infect these organs.