Book of Abstracts (PDF) - International Mycological Association

IMC7 Main Congress Theme III: PATHOGENS AND NUISANCES, FOOD AND MEDICINE Posters
progressive decrease in mannitol, arabitol and erythritol in
colonies as osmotic potential decreased to -8.4 MPa on
glycerol and NaCl amended media. However, on matrically
modified media there was an increase in arabitol with a
progressive decrease of glycerol and erythritol in colonies
as the matric potential was decreased. There were also
marked changes in the content of trehalose and glucose in
colonies of F. graminearum in relation to osmotic and
matric potential modification.
880 - Inhibition of biosinthesis of different mycotoxins
by using antioxidants alone or in association with food
preservatives
A. Ricelli 1 , P. Trionfetti-Nisini 2 , A.A. Fabbri 2 , M. Jestoi 3 ,
A. Rizzo 3 , L. Corazza 4 & C. Fanelli 2*
1 ISPA, CNR, Viale Einaudi 51, 70125 BARI, Italy. -
2 Università Roma "La Sapienza", Largo Cristina di Svezia
24, 00165 Roma, Italy. - 3 Nat. Veterinary Food Research
Institute, Hameentie 57, 00231 Helsinki, Finland. - 4 Ist.
Patologia Vegetale, MIPAF, Roma, Italy. - E-mail:
corrado.fanelli@uniroma1.it
The efficacy of different antioxidant compounds both
synthetic and of natural origin, alone or in combination, has
been tested in order to verify their action both on the
growth and on toxins production in different
mycotoxigenic fungi. In particular we have tested some of
the toxigenic fungi that often contaminate food and feed:
Aspergillus ochraceus and Penicillium verrucosum
(ochratoxin A producers), Fusarium graminearum
(Zearalenon producer), F. moniliforme and F. proliferatum
(fumonisins producers). The experiments have been
performed on wheat and maize seeds moistened up to a
water activity of 0.85 and 0.95 and incubated at 28 °C (A.
ochraceus and P. verrucosum) or at 25 °C (Fusaria strains)
for 30 days after the inoculum. The tested compounds were
BHA, BHT 0.02% w/v, K sorbate 0.2% w/v, Na propionate
0.2% w/v, resveratrol 10-4 and 10-3 M, ellagic acid 10-4
and 10-3 M, Lentinula edodes 4% w/v cultural filtrates
(LCF). Concerning both the ochratoxin A and fumonisin
producing fungi, the best results, both on the growth and on
toxin production (more than 80% inhibition) have been
observed with BHA and resveratrol on maize seeds and
with K sorbate or resveratrol on wheat seeds. In some cases
it has been detected a very high inhibition of ochratoxin A
production on wheat seeds also by using LCF Other
experiments are in progress in order to obtain a long-lasting
inhibiting effect. This work has been sponsored by grants
PL-QLRT-1999-433 and 966 of EC.
881 - Effect of fungicides commonly used for
Podosphaera leucotricha control on the powdery mildew
hyperparasite, Ampelomyces quisqualis
J.C. Russell 1 , X. Xu 2 & P. Jeffries 1*
1 Horticulture Research International, East Malling, Kent,
ME19 6BJ, U.K. - 2 University of Kent at Canterbury,
Canterbury, Kent, CT2 7NJ, U.K.
Apple powdery mildew, caused by Podosphaera
leucotricha, can significantly reduce crop yield. Severity
may increase with successive seasons, resulting in stunting
and distortion of leaves and general decline in tree health.
Current strategy for apple powdery mildew control relies
mainly on fungicide application at intervals of
approximately ten days throughout the growing season. A
biological control agent, using the hyperparasite
Ampelomyces quisqualis, is one possible way to reduce this
intensive chemical input. For it to be incorporated into the
current management practice the hyperparasite must
tolerate most commonly used fungicides. Eight isolates of
A. quisqualis, representing each of the eight ITS groups
(based on analysis by SSCP), and the commercial
formulation AQ10, were tested for their tolerance to
Systhane, Dorado, Nimrod, Topas, and Sulphur. The
effects of fungicide on spore germination and colony
growth were investigated. Dorado had no significant effect
on the rate of germination of isolate DSM 2223, but
otherwise all fungicides had a suppressive effect on spore
germination of the isolates examined. This suppression
varied between 15.28% for Systhane on isolate CBS
130.79 and 89.63% for Topas on isolate 265. Fungicide
application to established colonies seemed to have little
initial effect, but by 21 days post application hyphal growth
had been arrested. Sulphur and Systhane had the least and
the greatest effect on hyphal growth rate respectively.
882 - The main wheat leaf spot pathogens in the Czech
Republic in the last years
J. Sarova
Research Institute of Crop Production, Drnovska 507,
Prague 6 - Ruzyne, 161 06, Czech Republic. - E-mail:
sarova@vurv.cz
Leaf spot diseases of wheat are caused by different
pathogenic fungi. This study was focused on relatively new
wheat leaf spot diseases in the Czech Republic especially
on tan spot caused by Pyrenophora tritici-repentis (anam.
Drechslera tritici-repentis). The occurrence of wheat leaf
spot diseases was monitored in the Czech Republic in 2000
and 2001. The samples were collected from different
localities of the Czech Republic. Fungal pathogens were
determined with microscopic methods. Frequency of the
pathogens varied in both years because the occurrence of
fungal leaf spot pathogens depends on climatic factors
especially on the temperature, the humidity and the
precipitation. The most prevalent fungal leaf spot
Book of Abstracts 265