Penicillium crustosum Thom (1930) causes blue mold on pome fruits and is also regularly found on cheese, nuts, and soil (1,3). The fungus produces a wide range of mycotoxins such as penitrem A, roquefortine C, terrestric acid, and cyclopenol, which impact human health (1). In January and February 2013, 20 decayed apples, ‘Golden Delicious’ and ‘Jonagold’ (Malus × domestica Borkh.) with blue mold symptoms were collected from cold storages in Svilajnac and Bela Crkva, Serbia. Decayed areas were light to medium brown with blue green sporulation on the surface of the lesion. Decayed tissue was soft and watery with a sharp margin between the diseased and healthy areas. One isolate from each cultivar was designated JP2 (‘Golden Delicious’) and JBC7 (‘Jonagold’) and further characterized. Conidiophores of both isolates were terverticillate, stipes were septate with rough walls, and phialides were ampulliform. Conidia were smooth, borne in columns, and were spherical to subglobose. Conidial dimensions for JP2 were 3.2 to 4.56 (3.73) × 2.64 to 4.3 (3.32) μm and for JBC7 were 3.1 to 4.46 (3.65) × 2.81 to 4.27 (3.31) μm (n = 50). The isolates were cultured on Czapek yeast autolysate agar (CYA), malt extract agar (MEA), and yeast extract sucrose agar (YES) media and incubated at 25°C for 7 days. Mycelia were white with heavy sporulation yielding grayish green colonies on all media. Colonies were radially sulcate and velutinous, with clear exudate, and produced a yellow to orange reverse on CYA and YES. On MEA, colonies were plane, low, and mycelia subsurface with conidia having a dry powdery appearance. Crusts of conidial masses formed after 10 or more days. No growth was observed on CYA when these isolates were incubated at 37°C. Both isolates were identified as P. crustosum Thom using morphological characters according to (2) and (1). Species level identification was confirmed by isolating genomic DNA followed by amplification of the β-tubulin locus using gene specific primers via conventional PCR (4). MegaBLAST analysis of the 2X consensus nucleotide sequences revealed that JP2 and JBC7 (GenBank KJ433984 and 85) were 99% identical to P. crustosum culture collection isolate IBT 21518 (JN112030.1). Koch's postulates were examined using two apple cvs. Idared and Kolacara. Ten fruit per cultivar per isolate were inoculated on two sides of each fruit; 20 fruit were used as water-only inoculated controls. Fruit were washed with soap and water, surface sanitized with 70% ethanol, and placed into polyethylene boxes. Using a finishing nail, 4-mm wounds were created and inoculated with 50 μl of a 3 × 10⁵/ml conidial suspension or Tween-treated sterile distilled water. Boxes with inoculated and control fruit were stored at 25°C for 10 days. The inoculated fruit developed small, soft, watery lesions, which enlarged into decayed areas with defined edges and abundant sporulation on the surface. Symptoms were identical to the original ones, while the control fruit remained symptomless. The fungus was re-isolated from infected tissue and showed the same morphological characteristics as the original isolates, thus completing Koch's postulates. Blue mold occurs during long term storage of apples and is predominantly caused by P. expansum. This is the first report of P. crustosum causing postharvest blue mold decay on apple fruit obtained from storage in Serbia and indicates that P. crustosum is an emerging pathogen for the Serbian pome fruit growing and packing industry. References: (1) J. C. Frisvad and R. A. Samson. Stud. Mycol. 49:1, 2004. (2) J. I. Pitt and A. D. Hocking. Fungi and Food Spoilage, 239. Springer, 2009. (3) P. G. Sanderson and R. A. Spotts. Phytopathology 85:103. 1995. (4) P. L. Sholberg et al. Postharvest Biol. Technol. 36:41, 2005.

Brown rot, caused by Monilinia spp., is an economically important pre and postharvest disease of pome and stone fruits worldwide. In Serbia, apple is the most widely grown pome fruit, and the distribution of economically important Monilinia spp. responsible for apple brown rot is unknown. Hence, we conducted a three year survey, from 2010 to 2012, where 349 isolates were obtained from six orchards and four storage facilities from five different apple cultivars with brown rot symptoms. Morphological characterization of the isolates, multiplex PCR, and phylogenetic analysis revealed four species: M. fructigena, M. laxa, M. fructicola, and Monilia polystroma. All species were found in the orchard and in storage, with M. fructigena predominating, followed by M. polystroma. Representative isolates were analyzed in vitro and in vivo where differences in growth rate, sporulation, and virulence on apple fruit were observed. Findings from this investigation demonstrate diversity in the species responsible for pre ...

Penicillium polonicum K. Zaleski is an economically important airborne fungus with a broad host range including cereals, peanuts, onions, dried meats, citrus fruits, and yam tubers (2,4). Secondary metabolites produced by this species include harmful mycotoxins penicillic acid, verucosidin, and nephrotoxic glycopeptides, which may play a role in Balkan Endemic Nephropathy (2,5). In January 2013, decayed onion bulbs (Allium cepa L. cv. Meranto) with blue mold symptoms were found causing significant economic losses at a storage facility in Stara Pazova, Serbia, and were collected. The decayed area of the bulbs was pale yellow to light brown, and tissue was soft and watery. Bluish green sporulation was abundant on the surface and inside the bulb, between decayed scales. Two isolates (designated L1a and L4p) were obtained and further characterized using morphological and molecular methods. Colonies on potato dextrose agar (PDA), Czapek yeast autolysate agar (CYA), malt extract agar (MEA), and yeast extract sucrose agar (YES) media at 25°C after 7 days were blue green, velutinous, with clear exudate present on CYA. Colony reverse color on CYA and YES for both isolates were cream to yellow brown. The mean colony diameter on PDA for L1a was 29.89 ± 0.96 mm, and for L4p was 26 ± 0.37 mm; on CYA 32.56 ± 0.53 mm for L1a and 30.11 ± 2.42 mm for L4p; and on YES 33.86 ± 1.59 mm for L1a and 31.17 ± 1.83 mm for L4p. No growth was observed on CYA when isolates were incubated at 37°C. Conidiophores of both isolates were terverticillate, stipes were septate with smooth to finely roughened walls, and phialides were ampulliform. Conidia were globose to subglobose, smooth-walled, and borne in columns. Conidial dimensions for L4p were 2.72 to 3.82 (3.26) × 2.36 to 3.42 (2.95) μm, and for L1a were 2.87 to 4.39 (3.58) × 2.53 to 3.79 (3.16) μm (n = 50). Both isolates tested positive for the production of cyclopiazonic acid and other alkaloids, as indicated by a violet reaction for the Ehrlich test. Morphological characters of L1a and L4p were in accordance with those described for P. polonicum K. Zaleski (2). Genomic DNA was isolated using CTAB extraction method (1) and molecular identification was completed using gene specific primers for the β-tubulin locus (Bt-LEV-Up4/Bt-LEV-Lo1) via conventional PCR (3). The nucleotide sequences of amplified products (~800 bp) have been assigned to GenBank (KJ570971 and 72). MegaBLAST of obtained sequences showed a 99% similarity with several sequences of P. polonicum deposited in GenBank, which confirmed the morphological identification. Pathogenicity was tested by wound inoculation of 10 surface sanitized onion bulbs cv. Meranto with 50 μl of a 10⁵/ml conidial suspension from isolates grown on PDA. Ten control onion bulbs were wound-inoculated with Tween-treated sterile distilled water. After 30 days incubation in plastic containers, under high humidity at 22°C, typical symptoms of blue mold developed on inoculated bulbs, while non-inoculated controls remained symptomless. Isolates recovered from inoculated bulbs showed the same morphological characteristics as the original isolates, thus completing Koch's postulates. To our knowledge, this is the first report of P. polonicum on stored onion in Serbia. Results from this study indicate that a holistic approach to control this fungus should be implemented that may include one or all of the following: increased sanitation methods to eliminate inoculum, breeding for resistant onion cultivars, and integration of additional control methods to maintain onion quality during storage. References: (1) J. P. Day and R. C. Shattock. Eur. J. Plant Pathol 103:379, 1997. (2) J. C. Frisvad and R. A. Samson. Stud. Mycol. 49:1, 2004. (3) S. N. de Jong et al. Mycol. Res. 105:658, 2001. (4) W. K. Kim et al. Mycobiology 36:217, 2008. (5) P. G. Mantle. Facta Univ. Ser. Med. Biol. 9:64, 2002.