Cumulation of mycotoxins in maize cobs infected withFusarium gramihearum

Fusarium Poae (Peck) Wollenw. - Occurrence in maize ears, nivalenol production and mycotoxin accumulation in cobs

Fusarium poae (Peck) Wollenw. occurred In maize ears with "pink rot" during 1985-1993 up to 18% of Fusarium isolates, with maximum frequency in 1990. Nivalenol and fusarenone X were produced under laboratory conditions by 13 out of 14 isolates up to 115 μg/g and 13.3 μg/g respectively. The same isolates produced diacetoxyscirpenol (DAS) up to 21.7 μg/g and 15-monoacetoxyscirpenol (MAS) up to 12.3 μg/g. However, In none of the strain cultures were T-2 toxin and HT-2 toxin detected. In samples of naturally Infected maize grain nivalenol was detected at levels of 1.8-32.5 μg/g and fusarenone X was not present. In corresponding axial stems were present both nivalenol (up to 13.5 μg/g) and fusarenone X (up to 2.4 μg/g).

Occurrence and distribution of 13 trichothecene toxins in naturally contaminated maize plants in Germany

The objective of the present study was to monitor the occurrence and distribution of a spectrum of trichothecene toxins in different parts of maize plants. Therefore maize plants were sampled randomly from 13 fields in southwest Germany and the fractions kernels, cobs, husks, stalks, leaves and rudimentary ears were analyzed for eight A-type and five B-type trichothecenes. Each of the toxins was found in at least three of the total of 78 samples. The study revealed that both A-type and B-type trichothecenes may be present in all parts of the maize plant but may be unevenly distributed. For the contents of deoxynivalenol, 3- and 15-acetyldeoxynivalenol, nivalenol, scirpentriol, 15-monoacetoxyscirpenol, HT-2 and T-2 toxin significant differences (p < 0.05) were found between different parts of the maize plants whereas no significant differences were observed for fusarenon-X, 4,15-diacetoxyscirpenol, neosolaniol, T-2 triol and T-2 tetraol. Up to twelve toxins co-occurring in one sample were detected. As a group B-type trichothecenes dominated over A-type trichothecenes concerning incidences and levels. Contamination was strongest with rudimentary ears based on incidence and mean and maximum contents; mean contents with few exceptions tended towards a higher level than in other fractions with significant (p < 0.05) differences compared to leaves for seven toxins.

Occurrence of deoxynivalenol and Fusarium graminearum in Argentinian wheat

During the 1993 harvest period there was a high incidence of Fusarium head blight in wheat in Argentina. Fusarium species that produce trichothecenes in wheat have been reported in several countries including Argentina. Several studies have shown that F. graminerarum and deoxynivalenol (DON) were the main contaminants detected in wheat and by-products in Argentina. The objective of this study was to evaluate the occurrence of Fusarium spp. and DON contamination in wheat from Córdoba, Argentina during the 1993/94 harvest season. F. graminearum was the main Fusarium species isolated. From 40 samples analysed, 80% showed DON contamination. The levels of DON found ranged between 300 and 4500 micrograms/kg. There was good correlation between F. graminearum and DON contamination. Only five samples showed levels of DON higher than those established in the guidelines in Canada and the USA for food and feedstuffs.