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Apple (Malus domestica Borkh.) is a fruit traditionally grown in the Czech Republic, and tomatoes (Solanum lycopersicum Mill.), too, are widely raised in this region. Colletotrichum acutatum J. H. Simmonds is a polyphagous fungal plant pathogen. Earlier, this pathogen caused disease on strawberry in the Czech Republic (2), and now it has become an important pathogen on safflower (4). During the 2010 harvest, anthracnose symptoms were noticed on the fruits of apple and tomato. Infected apples fruits (localities Velká Bíteš and Znojmo) and tomatoes (localities Velká Bíteš and Žabčice) were collected. Typical symptoms on fruit surfaces were round, brown, shriveled and sunken spots, 1.2 to 2.0 cm, with orange conidial masses appearing on the spots. A fungus was isolated from each host on potato dextrose agar and cultured at 25 ± 2°C for 10 days. Mycelium was superficial, partly immersed, and white to gray with occurrence of orange conidial masses. Conidia of the tomato and apple isolates were colorless and fusiform. The size of conidia from the apple and tomato isolates, respectively, ranged from 11 to 15 × 2.5 to 3.5 μm and 11 to 16 × 2.5 to 4 μm. Morphological characteristics suggested that the isolated fungi was a Colletotrichum sp. To fulfill Koch's postulates, healthy tomato and apple fruits were disinfected with 3% sodium hypochlorite for 2 min and rinsed in sterile distilled water. Fruits were pinpricked with a sterile needle and 10 μl of a spore suspension (1 × 105 conidia ml–1) was inoculated by pipetting into the wound. Control fruits were treated with sterile distilled water. The fruits were transferred to a growth cabinet and maintained at a temperature of 25 ± 2°C, relative humidity of 70 ± 5%, and a photoperiod of 12 h. Similar disease symptoms as in the collected fruits were observed on tomato fruits at 7 days and apple fruits at 20 days after inoculation, while no symptoms appeared on control fruits. The pathogen was reisolated from infected fruits. Species determination of the isolates was confirmed by PCR. Specific primers designed in region ITS1, the 5.8S RNA gene, and region ITS2 of the pathogen DNA were selected. Specific primers CaInt2 and ITS4 were used to identify C. acutatum (3), and primers CgInt and ITS4 were used to determine C. gloeosporioides isolate CCM 177 (1), which was used as a control. Our isolates yielded PCR products (490 bp) only with primers designed for C. acutatum. The C. gloeosporioides isolate yielded a PCR product (450 bp) only with CgInt and ITS4 primers. PCR products were sequenced and identified with the BLAST program. The sequence of the tomato fruit isolate (Accession No. JN676199) and apple fruit isolate (Accession No. JN676198) matched with 100% similarity to the C. acutatum sequences in GenBank. The control isolate of C. gloeosporioides matched 100% to sequences AJ749682 and AJ749692. To our knowledge, this is the first report of C. acutatum on tomato and apple fruits in the Czech Republic. This pathogen can endanger the production and storage of apples and tomatoes in this region. References: (1) P. R. Mills et al. FEMS Microbiol. Lett. 98:137, 1992. (2) D. Novotný et al. Plant Dis. 91:1516, 2007. (3) S. Sreenivasaprasad et al. Plant Pathol. 45:650, 1996. (4) J. Víchová et al. Plant Dis. 95:79, 2011.

Gooseberry (Ribes uva-crispa L.) is a commonly grown fruit tree or bush in the Czech Republic. Colletotrichum acutatum J. H. Simmonds is a polyphagous fungal plant pathogen. This pathogen has been reported causing anthracnose on strawberry in the Czech Republic (2), and recently it has become an important pathogen on the fruits of apple and tomato (4). In 2012, anthracnose symptoms were noticed on fruits of gooseberry (locality Pribyslavice, near Brno). The symptoms on fruit surfaces were round, brown, shriveled, sunken spots of 1.2 to 2.0 cm, with orange conidial masses on the spots. The pathogen was isolated from symptomatic fruits on PDA and cultured at 25 ± 2°C. The color of colonies varied with age from white to gray with occurrence of orange conidial masses. Conidia were colorless and fusiform, size 13 to 17 × 4 to 5 μm (n = 100). The morphological characteristics classified the pathogen as a Colletotrichum sp. To fulfill Koch's postulates, 25 disinfested healthy gooseberry fruits were pinpricked by sterile needle and 10 μl of spore suspension (1 × 105 conidia ml–1) was inoculated by pipetting into the wound. Control fruits were treated with sterile distilled water. The fruits were transferred to a growth cabinet and maintained at a temperature of 25 ± 2°C, relative humidity 70 ± 5%. Similar anthracnose symptoms were observed on all of gooseberry fruits a week after inoculation, whereas no symptoms appeared on control fruits. The pathogen was reisolated from infected fruits. Species determination of the isolates was confirmed by PCR. Specific primers designed in region ITS1, the 5.8S RNA gene, and region ITS2 of the pathogen DNA were selected. Specific primers CaInt2 and ITS4 were used to identify C. acutatum (3), and primers CgInt and ITS4 were used to determine C. gloeosporioides isolate CCM 177 (1), which was used as a control. Our isolates yielded PCR products (size 490 bp) only with primers designed for C. acutatum. The C. gloeosporioides isolate yielded PCR product (size 450 bp) only with CgInt and ITS4 primers. PCR products were sequenced and identified with the BLAST program. The sequence of the gooseberry fruit isolates (Accession No. JX843763 and JX843764) matched with 100% similarity to the C. acutatum sequences in GenBank. To our knowledge, this is the first report of C. acutatum sensu lato on gooseberry fruits in the Czech Republic. This pathogen can endanger the production of gooseberry fruits in this region. References: (1) P. R. Mills et al. FEMS Microbiol. Lett., 98:137, 1992. (2) D. Novotný et al. Plant Dis. 91:1516, 2007. (3) S. Sreenivasaprasad et al. Plant Pathol. 45:650, 1996. (4) J. Víchová et al. Plant Dis. 96:769, 2012.

Laboratory tests of six isolates of the pathogen Colletotrichum acutatum from different host plants demonstrated the varying sensitivity of pathogen with regard to mycelium growth and conidial germination after treatment with seven fungicides containing various active ingredients. None of the evaluated isolates was tolerant to the selected active ingredients in the fungicides. In tests of mycelium growth sensitivity, isolates from lupin and strawberry were most frequently identified as the most sensitive of all evaluated fungicides. The safflower isolate, on the other hand, most frequently exhibited the lowest reaction to fungicides. Differences in conidial germination of individual isolates were not detected in fungicides with the active ingredients dithianon, folpet and mancozeb, for which inhibition reached 100% in almost all isolates. The most significant differences in sensitivity among individual isolates were recorded in fungicides with the active ingredients azoxystrobin and metiram. In the case of the fungicide with active ingredient azoxystrobin, the highest inhibitory effect was achieved in the safflower isolate and the lowest in the white lupin isolate. After treatment with the fungicide with active ingredient metiram, the lowest germination rate was recorded in isolates from safflower and strawberry and the highest in isolates from hypericum and lupin.

STAŇKOVA, B., VICHOVA, J., POKORNÝ, R.: Virulence of Colletotrichum acutatum isolates to several host plants. Acta univ. agric. et silvic. Mendel. Brun., 2011, LIX, No. 3, pp. 161–170 Colletotrichum acutatum belongs to polyphagous fungal pathogens and is widespread in many countries on all continents. C. acutatum causes the most serious economic damage in strawberry (Fragaria x ananassa Duch.). Considering the wide variability of the pathogen may be assumed spread to other areas which constitutes danger not only for strawberry, but also other economically important fruit crops, vegetables and fruits. The main objective of our study was to verify the cross infection of eleven C. acutatum isolates from diff erent host plants (strawberry, saffl ower, lupine, pepper and Hypericum perforatum) to selected host plants (strawberry, pepper and saffl ower). Two varieties from each of the experimental plant species were selected and virulence of isolates C. acutatum was evaluated. Based on results of statistical evaluation, virulence of C. acutatum isolates was diff erent on strawberry, pepper and saffl ower. The strawberry variety Pegasus was more susceptible to C. acutatum than the variety Elkas. Isolate 710 from H. perforatum showed the highest virulence for both varieties in terms of index of infection intensity. The pepper variety Pirouet was more susceptible than the variety Cynthia. The highest degree of virulence was found for isolate 29267 from pepper in the variety Cynthia, the highest virulence was proved for isolate 231 from strawberry in the variety Pirouet. No statistical diff erence was confi rmed between susceptibility of the saffl ower varieties. Isolate 1209 from saffl ower showed the most important eff ect on tested plants of saffl ower. Isolates 710 from H. perforatum, isolate 1209 from saffl ower, isolate 29267 from pepper and isolate 231 from strawberry showed diff erent virulence for tested host plants. Colletotrichum acutatum, saffl ower, strawberry, pepper, virulence, cross-infection

Optically transparent suspensions of (Degussa P25) titanium dioxide which mimic well the photochemical and photophysical properties of the bulk material were prepared by sequential centrifugation. Quantum yields of photocatalyzed oxidation of I − and of propanal were measured under monochromatic 313 nm irradiation and found to be very similar to those estimated for concentrated P25 slurries but higher than those measured in colloidal TiO 2 solutions. A unit limiting quantum yield for propanal photooxidation suggests very efficient utilization of photogenerated holes. Time-resolved absorption spectra were measured in the 50 ps-10 ns time interval following excitation by a 30 ps, 355 nm laser pulse and found to be definitely different from picosecond spectra observed earlier for TiO 2 colloids. It is proposed that the observed transient signal may arise from a photogenerated hole that undergoes thermalization and surface-trapping with a lifetime of approximately 1 ns.

Safflower (Carthamus tinctorius L.) is an oil crop that is suitable for dry growing conditions in the Czech Republic. Most of the Czech production is used as bird feed. Typical anthracnose symptoms were observed at one safflower field in the Moravia Region of the Czech Republic during the 2005 growing season. Since then, the disease has become widespread with 100% yield losses observed in several locations in 2009. Symptoms consisted of circular spots on leaves and stem blight characterized by dark-colored stem lesions bearing salmon-colored conidia masses in acervuli. A fungus was isolated from symptomatic safflower plants (cv. Sabina) on potato dextrose agar and incubated at 25°C as described by Kwon et al. (3). The color of fungal colonies changed from white to gray with age with salmon-orange pigmentation on the reverse side of plates. Similar observations had been reported by Jelev et al. (1). Conidia were colorless, fusiform, and measured 10 to 17 μm (mean 13.59) × 4 to 8 μm (mean 5.98). Morphology suggested a Colletotrichum sp. To fulfill Koch' postulates, safflower plants at the BBCH 12 growth stage (second leaf fully expanded) were spray inoculated with a conidia suspension (1 × 105 conidia/ml). Growth chamber conditions were temperature 20 ± 1°C, relative humidity 70 ± 5%, with a 16-h photoperiod. Control plants were treated with sterile distilled water. Typical anthracnose symptoms were observed 1 week after inoculation. Control plants were symptomless. The pathogen was reisolated from infected stems and leaves. PCR with primers CaInt2 and ITS4 was used to confirm the identification of a Colletotrichum sp. Reaction products obtained with these primers were approximately 500 bp long. The ribosomal DNA internal transcribed spacer region containing ITS1, 5.8S, and ITS2 of the isolate from safflower was sequenced and identified with the BLASTn program. The sequence matches with 100% similarity to the sequence of the Glomerella acutata teleomorph of Colletotrichum acutatum (GenBank Accession No. AB548282) and 100% similarity to C. simmondsii (GenBank Accession No. GU183359). C. acutatum and C. simmondsii can be distinguished from each other by pigment color (4), with the safflower isolate matching the description of C. simmondsii. Kim et al. (2) recorded C. acutatum on safflower fields in the Euiseong area of Korea in 1997. To our knowledge, this is the first report of C. simmondsii causing safflower anthracnose in the Czech Republic. References: (1) Z. J. Jelev et al. Plant Dis. 92:172, 2008. (2) W. G. Kim et al. Plant Pathol. J. 15:62, 1999. (3) J. H. Kwon et al. Plant Pathol. J. 15:172, 1999. (4) R. G. Shivas and Y. P. Tan. Fungal Divers. 39:111, 2009.