No abstract

Fusarium crookwellense KF748 (NRRL A-28100) (isolated from dry rotted potato tubers in Central Poland) produced six mycotoxins on both rice and corn substrates at 25°C. The metabolites detected were zearalenone, aL-trans-zearalenol, 0-trans-zearalenol, fusarin C, and the trichothecenes fusarenone X and nivalenol. This is the first report of formation of at-trans-zearalenol, 0-trans-zearalenol, fusarenone X, and nivalenol by F. crookwellense. The newly described species Fusarium crookwellense (8, 10) was found in Australia on cereals and potato tubers (1). Geographic distribution of F. crookwellense has been demonstrated from a variety of host plants and debris from soil in the United States, South Africa, France, Columbia, and China (1). Recently, F. crookwellense occurrence has been documented in Poland from blighted wheat heads and potato tubers (

The amount of diacetoxyscirpenol (DAS) produced by 14 isolates ofFusarium sambucinum under laboratory conditions has been examined. The isolates were obtained from potato tubers with dry rot symptoms. Yields of DAS ranged from 20 to 330 mg/kg of wheat grain culture (chemical analysis -TLC). Chemical analysis and biological tests showed very similar results.

During 1985 and 1986 seasons from potato tubers with dry not symptoms 50 cultures belonging to nineFusarium species were isolated and their ability to form mycotoxins has been examined. The dominating species were:F. sambucinum Fuckel-52%,F. avenaceum (Fr.) Sacc.-8%,F. crookwellense Burges, Nelson and Toussoun-8% andF. culmorum (W. G. Smith) Sacc.-8%. p ]In cultures growing on wheat kernels all 26 isolates ofF. sambucinum formed diacetoxyscirpenol (DAS) in the amount of 20-1000 mg/kg. F. culmorum isolates produced zearalenone (F-2), deoxynivalenol (DON) and 3-acetyldeoxynivalenol (3-AcDON),F. crookwellense- zearalenone,F. avenaceum andF. subglutinans Wollenw. and Reinking- moniliformin (1330 and 66 mg kg respectively). T-2 toxin, HT-2 toxin, nivalenol and fusarenon X were not produced by any of the examined isolates.

F. moniliforme and other species of Liseola section, F. culmorum, F. dlamini, and F. nygamai, were examined for their ability to produce gibberellic acid (GA3), fumonisins, trichothecenes, zearalenone, moniliformin, and bikaverin (TLC method) Gibberellic acid was produced by F. moniliforme strains in liquid medium and on rice kernels with a maximum concentration level of 470 mg/dm3 and 1 g/kg, respectively. No strain isolated in Poland produced GA3 High‐yielding gibberellic acid strains produced neither trichothecenes and fumonisins nor other tested compounds. Also the rest of strains of examined species did not produce trichothecenes and other mycotoxins except for fumonisins which were found in rice cultures of F. moniliforme, F. proliferatum, and F subglutinans Bikaverin was produced by F. moniliforme always together with fumonisins. Filtrates of liquid cultures of gibberellin producing strains were tested for their toxicity to brine shrimps larvae (Artemia salina). It was found that GA3 presence does not increase toxicity of these filtrates.