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Toxicity toA. salina, of the Fusarium metabolites: deoxynivalenol (DON), its acetylated derivatives (3- and 15-AcDON), zearalenone (ZON), neosolaniol (NEO), nivalenol (NIV), T-2, HT-2 toxins, has been examined and compared with toxicity of extracts of barley kernels (8 cultivars and 4 lines) inoculated withFusarium culmorum, F. graminearum andF. sporotrichioides respectively. Estimated LC50 values were expressed as relative toxicity (RT) in mg DON/kg for samples inoculated withF. culmorum, F. graminearum or in mg T-2/kg forF. sporotrichioides inoculations.Toxicity of extracts of the same genotype/line kernels was compared among different pathogens used for inoculation and differences in Fusarium head blight susceptibility of different genotypes/lines inoculated with the sameFusarium strain were found. Significant correlation between toxicity of extracts (LC50, RT) and toxic metabolites concentration was found ([Formula: see text]; P = 0.01).Bioassays withA. Salina offer a fast, easy and inexpensive method to examine cereal genotypes susceptibility to Fusarium head blight and mycotoxins accumulation in kernels.

The analysis of deoxynivalenol (DON) in naturally infected wheat samples, after having been separated into four fractions through laboratory sieves, showed very low levels of DON in the fraction of largest kernels >2.8 mm (0 up to 1 mg/kg). The highest concentration of DON was found in fractions 2.2 to 2.5 mm and <2.2mm with up to 14mg/kg and 15mg/kg DON, respectively. In two samples (fractions <2.2mm) nivalenol was detected in concentrations up to 1,4mg/kg.

The correlation between the amount of deoxynivalenol (DON) and the percentage ofFusarium damaged kernels (FDK) in samples of wheat and triticale was studied.Samples of naturally infected wheat grain, collected in 1986, 1987 and 1988 and of triticale collected in 1986 were used.Additionally, artificial inoculated wheat samples (10 genotypes inoculated with 3F. Culmorum strains of weak, medium and severe pathogenicity and samples of 10 triticale genotypes inoculated withF. culmorum. andF. graminearun) were studied. Using statistical methods (the variance analysis, method of least significant difference (LSD), orthogonal contrast (OC) and minimum within groups sum of squares criterion (MSSC)), the samples were divided into two groups with respect to the attribute DON/FDK.To the first group belong samples of wheat and triticale, of which the heads were artificially inoculated with severely pathogenic strainsF. culmorum. In the samples of this group the amount of DON in kernels damaged withFusarium increased by 0,46 mg/kg per 1% of FDK.In the second group, consisting of naturally infected samples and samples from artificially inoculated heads the amount of DON increased 0,30 mg DON/kg per 1% of FDK.The equation for the calculation of approximated amount of DON in farm and commercial lots of wheat and triticale after examination of percentage of FDK is given.

Maize cobs withFusarium ear rot were collected at 1986 season and five infected byFusarium graminearum were analyzed for presence of triohothecenes and zearalenone. Collected material was subsampled forFusarium damaged kernels and corresponding axial stems and healthy looking kernels. All investigated cobs contained deoxynivalenol (DON) (range 18.0-131.5 mg/kg) and zearalenone (ZEA) (range 0.38-2.17 mg/kg), in four cobs 15-acetyl-deoxynivalenol (15-AcDON) (range 5.2-6.2 mg/kg) was present and two cobs besides three all metabolites contained 3-acetyl-deoxynivalenol (3-AcD0N) (range 0.5-0.8 mg/kg).The average of individual toxins amount in axial stems: in mg/kg was equal to: DON - 110.36, ZEA - 4.57, 15-AcD0N - 16.66, and 3-AcD0N - 1.32.Fusarium damaged kernels contained in average the following amount (mg/kg) of: DON 77.00, ZEA 0.98, 15-AcD0N 3.78 and 3-AcD0N 0.06. Healthy looking kernels contained DON 1.96 mg/kg and ZEA 0.07 mg/kg only. Cooccurrence of 3-AcDON and 15-AcDON in two samples was an interesting finding. The amount of DON in total cob was highly correlated (r = 0.94) with percentage ofFusarium damaged kernels in given ear.

Microdochium nivale (Fusarium nivale) was found to be frequently occuring in Poland pathogen of small grain cereals heads, causing symptoms similar to those observed after infection ofFusarium species. In consecutive years since 1985 till 1989 the following percentage of wheat and rye ears infected withM. Nivale and withFusarium head blight symptoms was found: 34%, 21%, 42%, 9%, 46% (wheat) and 57%, 43%, 65%, 4%, 47% (rye) heads.However, in naturally infected rye and wheat samples (kernels and chaff), we did not detect toxins usually present in samples infected with fungi of genusFusarium - such as deoxynivalenol and derivatives. TypicalFusarium trichothecene metabolites were also not present in cultures of 11M. nivale strains, growing 3-5 weeks on rice (45% water content) at 20°C. Cultures of two typical isolates on wheat grain (strain KF 1124) and on rice (KF 245) were found to be non toxic to broiler chickens when present in amount 20-40% in their diet. It can be concluded thatM. nivale (F. nivale) representatives in Poland did not produce toxic metabolites neither under laboratory condition nor after cereal ears infection under field conditions.

The yield of diacetoxyscirpenol (DAS) production by F. sambucinum strain No KF 735, isolated from potato tuber with dry rot symptoms, cultured on solid media and on liquid medium, has been examined.The amount of DAS produced within 28 days at 25°C in the cultures grown on solid media (wheat, rye, rice, oats, corn, barley, triticale and malt) reached 238mg/kg±9 to 789±16mg/kg (mean ± standard error; n=3), on potato cubes -55±3mg/kg and on the potato extract -147±5mg/dcm(3).The best substracts for crystalline compound production were malt and barley grain.

The susceptibility of six winter wheat cultivars toFusarium head blight has beenstudied. The lowest infected plants intensity, mean degree of head damage and fusariosis index exhibited cultivar Grana which also cumulated the lowest amount of trichothecenes (DON and derivatives ). Possibility to produce NIV by Polish strains has been found.in F.graminearum.

Three wheat samples collected in 1987 in Central Poland and naturally infected withFusarium spp were analyzed for the presence ofFusarium spp andFusarium toxins. Heads were separated into three fractions: kernels with visibleFusarium damage, healthy looking kernels, and chaff + rachis.The samples contained deoxynivalenol (2.0 - 40.0μg/g), nivalenol (O.O1μg/g), 4,7-dideoxynivalenol (0.10 - 0.15μg/g). 15-acetyldeoxynivalenol (0.10-2.00 μg/g), 3-acetyldeoxynivalenol (O/1Oμg/g), and zearalenone (0.01-2.00μg/g).This is the first report about 15 - acetyldeoxynivalenol in European wheat and the co-occurrence of 3 - acetyldeoxynivalenol and 15-acetyldeoxynivalenol in the same sample of contaminated cereals.

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.

Extracts of the followingFusaria cultures, isolated from cereals were examined for toxicity to Artemia salina:F. avenaceum (6 isolates),F. crookwellense (7),F. graminearum (11),F. nivale (5) andF. Sporotrichioides (2). The same cultures, growing on wheat grain, were assayed also mycotoxins presence using TLC method. Most toxic were found cultures ofF. Sporotrichioides and results of bioassay was similar to results of their TLC analysis. We found cultures of newly described speciesF. Crookwellense to be more toxic than cultures ofF. Graminearum.

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.

Fusarium crookwellense /B.N. and T./ isolated from affected cereals in Poland formed zearalenone on wheat grain up to 602 mg/kg. Tested isolates have been found strong to severe pathogens of wheat, rye, triticale and barley seedlings and corn ears with pathogenicity similar to that ofF. culmorum andF. graminearum.

An improved TLC method ofFusaria metabolites detection and quantitation has been elaborated. A total 92 isolates of Discolor sectionFusaria from cereals and potato have been examined from the point of view of cultures morphology and ability to produce characteristic mycotoxins. Low nutrient media (CLA, SNA) were found as suitable for production of uniform and typical macroconidia in studied cultures. All 26 isolates ofF. sambucinum Fuckel (=F.sulphureum, Schlecht) formed diacetoxyscirpenol in amount 20-1000 mg/kg and all 17.F. crookwellense Burgess N. & T. produced zearalenone (16-602 mg/kg).F. graminearum Schwabe produced: zearalenone 14/14 isolates, deoxynivalenol 11/14 isolates, both up to 77 mg/kg. Out of 26F. culmorum cultures originating from Poland 22 produced zearalenone up to 675 mg/kg, 17/26 3 acetyldeoxynivalenol up to 280 mg/kg and 16/26 deoxynivalenol up to 220 mg/kg. The difference in metabolism agrees with the difference in morphology of those species.

Naturally infected ears of corn were examined for presence of mycotoxins and colonizingFusaria. In kernels of cobs with symptoms of pink fusariosis /pink ear rot/ which stated about 95% cobs naturally infected was present moniliformin in amount 30-530 mg/kg.Fusarium suhglutinans /W&R/N,T&M was dominating species in this type of ear fusariosis. In handly selected kermels of cobs with symptoms of red fusariosis /red ear rot/ which stated only about 5% of infected cobs, were present: zearalenone up 20 mg/kg, deoxynivalenol /vomitoxin/ up 170 mg/kg and 3-acetyldeoxynivalenol up 40 mg/kg. In axial stems the amount of mycotoxins was 1.5-8 times higer than in kernels.

A single isolates ofFusarium graminearum Schwabe KF 366 andFusarium culmorum (W.G.Sm.) Sacc. KF 365 were used to infect 10 genotypes (9 lines and one cultivar) of winter triticale, 1 rye cultivar and 1 wheat cultivar, and amounts of mycotoxins in kernels were analysed at the same stage of development. One genotype of triticale CHD 353/79 and rye "Chodan" were found to be most resistant towards both species infection with lowest amount of mycotoxins (deoxynivalenol) content in kernels and also the lowest yield reduction. The most susceptible line CZR 142 cumulated in kernels about ten times higher amount of mycotoxins (up 53 mg DON/kg and 16 mg 3AcDON/kg, and 5 mg zearalenone/kg). GenerallyF, culmorum formed higher level of mycotoxins in kernels of infected heads thanF. graminearum. In kernels of more susceptible genotypes except deoxynivalenol, 3 acetyldeoxynivalenol and zearalenone also were present.

The occurrence of wheat head fusariosis in various regions of Poland was observed in 1985 and 1986. The incidence of fusariosis was usually low - about 0,01% - only on South - East in some localities reached 5 - 20%. The most important species isolated from infected heads were :Fusarium culmorum F.grami nearurn,F.ni vale andF.avenaceum, in addition to whichF.crookwel1ense,F.eqiseti,F.subqluti nans andF.tricinctum (sensu Nelson et al.1983) were observed. Deoxynivalenol was present in 100% examined kernels subsamples at level 5-18 mg/kg and 3-acetyl deoxyn i val enol in 70% at level 1-3 mg/kg. The mycotoxins amount in chaff was 1,4 to 2,6 and 1,4 to 11 times higher (DON and 3AcD0N resp.) than in kernels.

Fusarium species infecting heads of Triticale and mycotoxins presence in infected kernels and chaff were studied during two seasons. The most important species observed on infected heads were in 1986F. avenaceum (39%),F. nivale (21%),F. culmorum (20%),F. graminearum (14%), and others (6%). In 1987 after long and snowy winterF. nivale dominated (64%), followed byF. avenaceum (24%),F. culmorum (6%), andF. graminearum (5%).The mycotoxins deoxynivalenol (DON) and 3-acetyl DON were present in all 11 subsamples of kernels from heads infected byF. culmorum and/orF. Graminearum (1.6-16.4 mg and 0.7-2.4mg/kg, respectively). Chaff from the same subsamples contained 9.9-33.2mg/kg of DON and 5.2-16.0mg/kg of 3-AcDON. Kernels with visibleFusarium-damage contained 2.4-31.2 mg/kg of DON and 1.2-6.0 mg/kg of 3-AcDON. Remaining part of kernels without symptoms of visibleFusarium-damage contained only DON in an amount of 0.9-5.9 mg/kg.