Pink Mold Research Articles

First report of Trichoderma roseum causing tea leaf rot in China.

Tea (Camellia sinensis) is consumed worldwide for its numerous benefits and China lead the world production. In March 2023, leaf spots were observed on approximately 10% of tea plants in a 50-ha commercial tea plantation in Menghai (21°46'13"N, 100°30'6"E), Yunnan, China. Initial symptoms appeared as small spots, which progressively expanded and spread over the entire leaf surface. Subsequently, pale pink mold layers developed from the lesions (Fig. S1). To isolate the pathogen, small leaf pieces (3 × 3 mm) were cut from the margins of the lesions, sterilized with 75% ethanol for 30 sec and 0.5% NaClO for another 30 sec, and rinsed three times with sterile water. The pieces were placed on acidified potato dextrose agar (PDA) plates and incubated in darkness at 28°C. A total of 15 fungal isolates with identical morphologies were collected. The colonies appeared pale pink with white mycelia initially then turned orange-pink at the center and light white at the edges. After 10-15 days, exhibiting a powdery texture and concentric rings with uniform edges. Conidia were found at the apex peduncle and were inverted pear-shaped or oval, either non-septate (15.3 ± 2 × 7.8 ± 1.8 μm in size, n = 60) or septate, with a slightly constricted spore base featuring papillary projecvtions (14.8 ± 1.5 × 7.4 ± 0.7 μm in size, n = 60). The morphology closely resembled Trichoderma roseum (Oh et al. 2014). To confirm the species, the strain CYB5 was selected for identification by sequencing the ribosomal internal transcribed spacer (ITS) and large subunit (LSU) genes using polymerase chain reaction (PCR) (White et al.1990). The ITS (GenBank accession OR889657) and LSU (PQ270526) gene sequences exhibited 98% similarity with the Trichoderma roseum sequence KP317992 from NCBI database. A phylogenetic tree was constructed using MEGA 11 (Felsenstein 1981) based on the concatenated sequences (ITS and LSU) of the strain CYB5 and reference strains (Fig. S2). The analysis confirmed that CYB5 is T. roseum (Inácio et al. 2011). Pathogenicity tests were conducted on detached healthy tea leaves placed on wet filter paper in petri dishes. Micro-wounds were made on leaves using a sterilized needle, followed by inoculation with a 6-mm plug of CYB5. Control leaves were inoculates with fungus-free agar disks. The dishes were incubated at 25°C in the dark for 7 days. The leaves inoculated with CYB5 developed reddish brown to dark brown lesions around the inoculated sites, while control leaves remained asymptomatic. The fungus was reisolated from the lesion, and the isolates were morphologically identical to the original cultures. A second pathogenicity test was conducted on potted tea plants of the cultivar 'Yunkang No. 10.' Three plants scratched with a needle and three non-wounded plants were inoculated by spraying 20 ml of a spore suspension (105 spores/ml) of CYB5. Plants sprayed with sterile water served as controls. All plants were maintained in a growth chamber at 28°C, and 70% relative humidity. The lesions developed three days post-inoculation, and typical symptoms appeared after 10 days on spore-inoculated plants only. T. roseum was reisolated and reidentified based on the morphology and molecular analyses, thus fulfilling Koch's postulates. To our best knowledge, this is the first report of T. roseum causing tea leaf rot in China.

First report of Trichothecium roseum causing pink mould on strawberry fruit in Iran

First report of <i>Trichothecium roseum</i> causing pink mould on strawberry fruit in Iran

Antifungal activities of different plant extracts against pink mold of banana caused by &lt;i&gt;Trichothecium roseum&lt;/i&gt; (Pers.) Link

Trichothecium roseum (Pers.) Link causes pink mold rot in banana fruits across the world. Due to this infection, 30% of losses arise in poor man’s food. To control this disease, plant extracts show an alternative to fungicides. In this study, 40 plant species were screened for their antifungal activity against T. roseum. Among 40 hot and cold aqueous extracts of plant species, only 10% Allium sativum and 6% and 8% of Mansoa allicea showed 100% inhibition of T. roseum. Freezing condition (4°C) shows 100% inhibition compared to room temperature (27°C) and incubation temperature (46°C). One hundred per cent inhibition of T. roseum was observed within 5 days compared to 15, 20 and 30 days of incubation. The pink mold of banana caused by T. roseum was reported for the first time in Karnataka.

Identifi cation of the Postharvest Pink Mold Rot Fungus (Trichothecium roseum) on Grapes in China

Grape is an important crop due to its consumption as fresh fruit as well as the secondary products developed from the berries such as wines, jams, juice, jellies, and vinegar. Postharvest losses in grapes can adversely affect their market value and the quality of the secondary products developed from grapes. These losses can be due to pathogenic infections and other damage due to improper handling and storage practices. During a brief survey of the cold storage facilities of the Beijing Academy of Forestry and Pomology Sciences, grape berries showing postharvest rot symptoms were collected. Further onsite observations suggested that the disease was postharvest pink mold rot caused by Trichothecium roseum. Trichothecium roseum is an asexually reproducing soil-borne fungus with an unknown sexual morph. This fungus is known to cause postharvest diseases in many fruits and vegetables around the world. Our objective in this study was to report the fi rst occurrence of pink rot on grapes caused by T. roseum with molecular phylogeny, morphological studies, and pathogenicity tests. Also, this is the fi rst report of T. roseum from grapes in China.

First report of Corn Ear Rot Caused by Fusarium asiaticum in China.

Corn (Zea maysL.) ear rot, caused by various pathogens, is one of the most significant diseasesofcorn worldwide. In September 2020, a survey was undertaken to identify pathogenic fungi associated with corn ear rot in Suihua city (46.63°N 126.98°E), Heilongjiang Province, China. The average disease incidence was 14.2% and 15.6% in each of two fields sampled (~5 ha) usingafive-pointmethod (100 plants/each point). Twenty tissue samples from 20 diseased ears, showing white or pink mold on the surface of corn ears, were surface disinfected in 0.5% NaOCl for 5 min, rinsed 3 times in autoclaved distilled water. After drying, four treated corn kernels (one kernel/each ear) were placed onto potato dextrose agar (PDA) amended with 50 µg/mL streptomycin. The plates were sealed with parafilm sealing film and cultured in the dark at 26℃ with 80% RH for 3 days inanincubator. A total of 12 morphologically similar fungal isolates were obtained and subcultured by transferring hyphal tips for 3-5 days. Single-conidium isolates were generated with methods reported previously (Leslie and Summerell 2006). Colonies on PDA, reaching 20.3-20.9 mm·d-1 at 26℃, consisted of white to pale yellow, locculent, lush and dense aerial mycelium with red to apricot color. Macroconidia of six isolates randomly selected on carnation leaf agar (CLA) were falciform with a foot cell, three- to six-septate, measuring 12.6-67.2 × 2.6-5.4 µm (n = 100) in the dark at 26℃ with 80% RH for 5 days. No microconidia were observed. Based on these characteristics, the isolates were preliminarily identified asFusarium asiaticum (Chang et al. 2020; Leslie and Summerell 2006). Genomic DNA of three representative isolates YSF2, YSF4 and YSF7 were extracted and the translation elongation factor 1-α (TEF-1ɑ) gene was amplified and sequenced using the primers EF1-728F/EF1-986R (Carbone and Kohn 1999). The DNA sequences of YSF2, YSF4 and YSF7 were deposited in GenBank (OL631287.1, OP272129 and OP272130). Analysis of TEF-1ɑ sequences of YSF2, YSF4 and YSF7 showed that they were 100% identical to F. asiaticumisolates NRRL 26156 (AF212452.1) in NCBI and NRRL 13818 (AF212451.1) in Fusarium MLST. A pathogenicity test was performed on corn cv. Xinxin 1. Four days after silk emergence, 3 mL conidial suspension (106 macroconidia/ml) of each 12 isolates was individually injected into the center of the ear through the husk sideways, penetrating the kernels to a depth of about 5 mm (6 ears/each isolate) in the field (Guo et al. 2020). Six corn ears treated with sterile distilled water were used as the control. After inoculation, normal field management was carried out. All inoculated ears showed symptoms similar to those observed in the field 50 days after inoculation, while no symptoms were observed on the blank control ears. Five fungal isolates with the same colony morphology as the naturally occurring ear rot in the field were re-isolated from the inoculated corn kernels and confirmed to be F. asiaticum according to morphological characteristics and sequence analysis of five fungal isolates. F. asiaticum has previously been reported to cause corn ear rots in Japan (Kawakami et al. 2015). To our knowledge, this is the first report of F. asiaticum causing corn ear rot in Northeast China. Corn ear rot poses a threat to significantly reduce the quality of corn in a major production zone of maize in China. Therefore, its distribution needs to be investigated and effective disease management strategies developed.

First Report of a New Disease Caused by Fusarium tricinctum on Apple Tree in China.

First Report of a New Disease Caused by Fusarium tricinctum on Apple Tree in China.

Integrated Management of Mouldy Core and Pink Mould Rot of Apples in Storage under Controlled Atmosphere Conditions

Effect of pre-cooling, hot water treatment, fumigation, an antagonist (Bacillus subtilis) along with treatment of apple fruits with extract of Emblica officinalis (amla) and coating with neem oil was evaluated for their activity against the fungal growth of Alternaria alternata and Trichothecium roseum, the causal agents of mouldy core and pink mould rot, respectively. Impregnation of fruit trays with botanical formulations was also integrated with other treatments before placing the treated and untreated fruits in controlled atmosphere (CA) storage for four months. The integration of hydro cooling with ice water+CaCl2 (HIWC)+fruit skin coating with neem oil (1%)+placing treated fruits on botanical formulation (BF) impregnated fruit trays (treatment combination T7) prior to CA storage gave highest inhibition of the pathogenic tested fungi with rot incidence of 16.05, 20.46% and fruit rot of 9.05, 11.46%, respectively. The treatment combination T6 in which the antagonist B. subtilis was integrated with pre-cooling and BF-impregnated trays was the next effective treatment with rot incidence of 20.35, 23.07% and fruit rot of 13.34, 17.08%, respectively.

First Report of Fusarium avenaceum Causing Stem Rot on Polygonatum cyrtonema in Sichuan, China

Polygonatum cyrtonema Hua, which is an important perennial medicinal herb used for the treatment of diabetes and asthma, is planted extensively in China. In May 2018, the plants showed leaf wilt and severe stem rot symptoms. A survey showed 5% of the collected plants were diseased, with pink mold on the stem in the greenhouse and the wild in Sichuan Province. Over time, the necrosis extended around the stem so that the plants collapsed. Morphological and molecular analyses were carried out to confirm the causal agent. Six diseased plant tissues were surface disinfested with 75% ethanol for 30 s, 0.1% HgCl₂ for 1 min, rinsed in sterile water, dried, transferred onto potato dextrose agar (PDA), and incubated at 25°C for 7 days. Morphological characteristics were observed on PDA and synthetic low nutrient agar (SNA) (Garcia-Nunez et al. 2016). The genomic DNA of the isolates was extracted and sequenced to confirm the identity by rDNA internal transcribed spacer (ITS) region, the translation elongation factor 1-alpha (TEF-1α) gene, β-tubulin (TUB2), RNA polymerase II largest-subunit gene (RPB2), and large subunit (LSU) rDNA with primer pairs ITS4/ITS5, EF1/EF2 (O’Donnell et al. 1998), T1/T22 (Wang et al. 2014), fRPB2-5F/fRPB2-7CR (Liu et al. 1999), and LROR/LR5 (Rehner and Samuels 1994; Vilgalys and Hester 1990), respectively. Three isolates from diseased stems with similar morphology were isolated from single spores. Colonies on PDA grew rapidly and generated aerial mycelia with white to orange floccose and carmine to rose pigmentation on the reverse. On SNA medium, macroconidia were falcate, slender, curved with an elongated apical cell, usually three to five septa, measured 22.93 to 57.88 × 2.82 to 5.43 μm (n = 50), and occasionally one to two septa, 18.71 to 26.79 × 2.21 to 4.90 μm (n = 50). Microconidia were usually one-septate, hyaline, ovoid, smooth, and measured 10.09 to 19.39 × 2.22 to 4.28 μm (n = 50). Chlamydospores were not observed. The newly generated sequences (ITS, 561 bp, MK204577; TEF-1α, 673 bp, MK226333; TUB2, 1,261 bp, MK253102; RPB2, 1,125 bp, MK396098; and LSU, 885 bp, MK392034) of the isolate SICAUCC18-0001 indicated that those molecular data had high identity with those of Fusarium avenaceum (Fr.) Sacc. (ITS, KP265354 [100%], KP265365 [100%]; TEF-1α, MG670378 [100%]; TUB2, KY055838 [99%], KP170733 [99%]; RPB2, GQ915486 [99%]; and LSU, MH866319 [100%], MG274300 [100%], MG274299 [100%]) obtained from Solanum tuberosum L., wheat, Beta vulgaris L., and Vitis amurensis Rupr., respectively. The identification was confirmed by multilocus phylogenetic analysis. Based on morphological features and phylogenetic analysis, this fungus was identified as F. avenaceum (Garcia-Nunez et al. 2016). To complete Koch’s postulates, a pathogenicity test of the F. avenaceum was performed on sterile stems of P. cyrtonema. Ten stems wounded with a sterile toothpick were smeared with 20 μl of conidial suspension (1 × 10⁶ conidia/ml). Control plants were treated with sterile distilled water. Plants were placed in an aseptic incubator at 25°C and 95% relative humidity with 12-h light/dark. Seven days later, the inoculated plants developed symptoms similar to those observed in the field, and the controls were asymptomatic. The pathogens were successfully isolated from symptomatic stems. To our knowledge, this is the first report of F. avenaceum causing stem rot on P. cyrtonema.

Evaluation of Antioxidant Activities and Antifungal Activity of Different Plants Species Against Pink Mold Rot-Causing Trichothecium roseum

Trichothecium roseum causes the pink mold rot in many fruits and vegetables around the world. Due to this infection, significant losses arise in foods. In order to control this infection, plant extracts offer alternative treatment for fungicides. In this study, 50 plant species were screened for their antifungal effects against T. roseum. Anthemis arvensis, Origanum vulgare, Sambucus ebulus and Thymus longicaulis powders totally inhibited the mycelia growth of T. roseum at 10% (w/v). The powders of Chelidonium majus and Clinopodium vulgare were effective to T. roseum, with a percentage of inhibition of mycelia growth higher than 70%. MIC of A. arvensis aqueous extracts were lower than the other extracts (125 \(\upmu \hbox {g}\)/ml). Also its extracts inhibited the spore germination by 100% at 1000 \(\upmu \hbox {g}\)/ml. The incidence of the pink mold rot on tomatoes which were treated with C. majus aqueous extracts (75, 150 and 300 mg/ml) was lower than the extracts of other plants when compared to control. At concentration of 300 mg/ml, C. majus extracts prevented the disease by 71.42%. By the SEM, it was determined at the 4MIC extracts, cell wall degradation, swelling, flattening, lysis, collapsing and wrinkling on the hyphal structure. The highest total phenolic and flavanol contents were observed in O. vulgare extracts (310.49 mg GA/g) and T. longicaulis (5.24 mg CE/g). The \(\hbox {EC}_{50}\) values of the experimented extracts were lowered than the \(\hbox {EC}_{50}\) value of Gallic acid (1.87 mg/ml). Meanwhile, in all of the extracts there were phenolic compounds, protocatechuic, chlorogenic, caffeic acid and kaempferol as determined with HPLC system. This research demonstrates that C. majus aqueous extracts may possess high potential to control the pink mold rot on tomatoes as new natural antifungal products.

Gibberella ear rot of corn caused by Fusarium asiaticum in Japan

Ear rot with white or pink mold was found on corn (Zea mays L.). A species of Fusarium, not registered previously as a pathogen causing Gibberella ear rot of corn in Japan, was isolated from the rotted ear. The isolates, identified as F. asiaticum based on morphological characteristics and nucleotide sequences, caused white or pink mold on corn ear after inoculation. Moreover, the 3-acetyl deoxynivalenol chemotype and the nivalenol chemotype were found in the isolates. We propose to include F. asiaticum as one of the pathogens causing Gibberella ear rot of corn in Japan.

Trichothecium roseum에 의한 사과 분홍빛열매썩음병 발생

2012년 경상남도 진주시 농산물도매시장에서 구입한 사과에서 분홍빛열매썩음병이 발생하였다. 병징은 사과 과실 표면이 갈색으로 변하면서 약간 함몰되어지고 수침상으로 물러지고 썩으면서 그 위에 분홍빛 곰팡이가 형성되었다. 감자한천배지 위에서 균총의 색깔은 처음 흰색이고 배양기간이 경과됨에 따라 분홍빛의 분생포자가 많이 형성되었다. 균사생육 적온은 <TEX>$25^{\circ}C$</TEX>이었다. 분생포자의 모양은 서양배형이며 좌우 지그자그로 부착하며 성숙한 분생포자는 2개의 세포로 되어있다. 크기는 <TEX>$12-26{\times}8-12{\mu}m$</TEX>이었다. 분생자경은 균사표면에 직립으로 형성하고, 폭이 <TEX>$4-5{\mu}m$</TEX>이고 무색이었다. 위와 같은 결과를 통해 사과에서 발생한 병징과 병원균의 균학적 특징을 기초로 하여 이 병을 Trichothecium roseum (Pers.) Link ex Gray에 의한 사과 분홍빛열매썩음병으로 명명하고자 제안한다. In 2012, a pink mold rot was observed on apple (Malus pumila var. dulcissima Koidz.) at the Wholesale Market for Agricultural Products, Jinju, Korea. The first symptom of pink mold rot on apple fruit is a water-soaked appearance of the affected tissue and surface fruit formed pink mold rot, then became brown and produced a mass of powdery pink conidia spores. Colony was fast growing colonies, pinksh, zonate in diurnal rhythm, powdery from conidia. Optimum temperature for mycelial growth was <TEX>$25^{\circ}C$</TEX>. Conidia were hyaline, smooth, two-celled, thick-walled conidia with truncate bases, ellipsoidal to pyriform, and characteristically held together zig-zag chains and <TEX>$12-26{\times}8-12{\mu}m$</TEX> in size. Conidiophore was erect, colorless, unbranched, and <TEX>$4-5{\mu}m$</TEX> wide. On the basis of mycological characteristics, pathogenicity test, and molecular identification with the ITS region, the causal fungus was identified as Trichothecium roseum (Pers.) Link ex Gray.

Trichothecium roseum에 의한 감귤 분홍빛열매썩음병 발생

2012년 경상남도 진주시 농산물도매시장에 판매중인 감귤에서 분홍빛열매썩음병이 발생하였다. 병징은 감귤 과실 표면이 수침상으로 물러지고 썩으면서 그 위에 분홍빛 곰팡이가 많이 형성되었다. 균총의 색깔은 처음에 흰색이고 배양기간이 경과됨에 따라 배지 표면에 분홍빛의 분생포자가 많이 형성되었다. 균사생육 적온은 <TEX>$25^{\circ}C$</TEX>이었다. 분생포자의 모양은 서양배형이며 좌우 zigzag로 부착하며 성숙한 분생포자는 2세포로 되어 있으며 크기는 <TEX>$12-26{\times}8-12{\mu}m$</TEX>이었다. 분생자경은 균사표면에 직립으로 형성하고, 폭이 4-5 <TEX>${\mu}m$</TEX>이고 무색이었다. rDNA의 complete internal transcribed spacer(ITS) 영역의 염기서열을 분석하였고, 분석된 염기서열(613 bp)을 BLASTN 프로그램으로 확인한 결과, Trichothecium roseum와 99%의 상동성을 나타내었다. 이와 같이 감귤에서 발생한 병징과 병원균의 균학적 특징을 기초로 하여 이 병을 Trichothecium roseum(Pers.) Link ex Gray에 의한 감귤 분홍빛열매썩음병으로 명명하고자 제안한다. In 2012, a pink mold rot was observed on unishiu orange (Citrus unshiu Mac.) fruits at the Wholesale Market for Agricultural Products, Jinju, Korea. The symptom on unishiu orange was a water-soaked lesion on the surface of fruit, which later on enlarged to form softened brown rot lesions. The diseased fruits were covered with pink-colored mold, consisting of conidia and conidiophores of the pathogen. Optimum temperature for mycelial growth was <TEX>$25^{\circ}C$</TEX>. Conidia were hyaline, smooth, 2-celled, and thick-walled conidia with truncate bases, ellipsoidal to pyriform, characteristically held together zig-zag chains and <TEX>$12-26{\times}8-12{\mu}m$</TEX> in size. Conidiophore was erect, colorless, unbranched, and 4-5 <TEX>${\mu}m$</TEX> wide. On the basis of mycological characteristics, pathogenicity test, and molecular analysis with complete ITS rDNA region, the causal fungus was identified as Trichothecium roseum (Pers.) Link ex Gray. This is the first report of pink mold rot caused by T. roseum on unishiu orange in Korea.

The occurrence of pink mold rot fungus Trichothecium roseum on tomatoes in Korea

Trichothecium roseum DUCC502 was isolated from leaves of tomato plants at a greenhouse located in Buyeo, Chungchungnamdo. The colony color of the isolate was white initially and became pale pink on potato dextrose agar and oatmeal agar. Conidiophores of the isolate were long and slender, unbranched, and 73 – 112 x 2.1 – 3.3 µm in size. Its conidia were two-celled, hyaline colored, and ovoid or ellipsoid shaped, and11 – 18.3 x 6.1 – 8.5 µm in size. The 28S rDNA sequence analysis of the isolate showed it shared 99% similarity with that of T. roseum CBS113334. Mycelia of the isolate grew well on PDA plates under the conditions of pH 7–9 and temperature 20–25℃, respectively. A pathogenicity test showed the isolate caused necrotic regions and produced white to pale pink mycelia with spores on the surface of tomato fruits and leaves. This fungus was sensitive to benomyl and tebuconazole but less sensitive to dimethomorph, triflumizole and azoxystobin at 10 ug/ml concentration. Key words: Fungicide sensitivity, pink mold rot, postharvest disease, tomato,Trichothecium roseum.

Trichothecium roseum에 의한 토마토 분홍빛열매썩음병 발생

2005년 7월 경기도 파주시 시설재배 농가에서 완숙토마토 과실의 배꼽 부위가 암갈색으로 변하면서 낙과되는 피해가 발생하였다. 병반 표면에 옅은 분홍색의 곰팡이가 형성된 것을 확인할 수 있었으며, 병든 식물체에서 병원균을 분리하여 균학적 특징을 검토한 결과 Trichothecium roseum으로 동정되었다. 따라서 본 연구에서 얻어진 결과를 가지고 이 병을 T. roseum에 의한 토마토 분홍빛열매썩음병으로 제안하고자 한다. Pink mold rot of tomato occurred very severly on tomato farm in Paju, Gyounggi Province, Korea, in July 2005. The infected fruits were dropped and abandoned and the symptoms were similar to calcium deficient tomatoes. But symptom was a slight water-soaked area on or near the blossom end of the fruit and firm greyish-brown lesions were most found at the blossom-end of affected fruits. lesions caused by the pink mold fungus possess a water soaked margin and rise to characteristic orange-pink spores. Also when the diseased tomato was cut, the inside of tomatoes showed completely rotted with pink mold. The causal fungus was identified as Trichothecium roseum based on mycological characteristics. This is the first report of T. roseum infecting greenhouse tomatoes in Korea.

Occurrence of Pink Mold Rot of Strawberry Caused by Trichothecium roseum in Korea

Occurrence of Pink Mold Rot of Strawberry Caused by Trichothecium roseum in Korea

Pink mould of pecan kernels in the southeastern USA is associated with scab, above-normal temperatures, and humidity during nut maturation

SummaryPink mould is a disease caused by the common saprophytic fungus Trichothecium roseum (Pers.:Fr.). Pink mould rarely infects kernels of pecan [Carya illinoinensis (Wangeh.) C. Koch] in the southeastern USA, but the disease was a major problem in 2002. T. roseum enters the pecan fruit via scab lesions on the shuck caused by the fungus Fusicladoporium effusum, (G. Winters) Partridge & Morgan-Jones. This study examined the association between pink mould and weather during nut maturation. Average daily temperatures and two or more consecutive days of rainfall were identified as critical factors in 2002, and were compared with weather data between 1963 – 2001 when there was no recorded evidence of pink mould. Both the average daily temperatures and the number of consecutive rainy days during nut maturation were above the 40-year average in 2002. Consecutive rainy days during the nut drying period in 2002 were more than double the 40-year mean, implicating humidity as a critical factor in mould development at this time. Normal variations in temperature were minor factors in disease development following the initial infection. Thus, the onset of mould was associated with the development of scab lesions in late July, a combination of warm temperatures in September and October, and above-average humidity in September and during nut drying from mid-October until mid-November. This combination of factors occurred in only one year out of the past 41 years, explaining the rarity of the disease. The incidence of mould was sigmoidal, with the log-phase overlapping the period of rapid sugar accumulation in the kernel, and potential substrates for the mould to grow.

8-Deoxy-trichothecin production by Spicellum roseum isolated from a cultivated mushroom in Japan.

Ex-type culture of Spicellum roseum isolated from silage in France has been known to produce some trichothecenes. As the causative agent of the pink mold damping-off disease, we isolated some strains of S. roseum from a cultivated mushroom Flammulina velutipes at Nagano, Japan. To examine whether the Japanese strains of S. roseum produce trichothecenes or not, the isolates were cultivated on rice medium and extraction was made for mycotoxin analysis. 8-Deoxy-trichothecin was accordingly detected and confirmed with GC/MS by means of EI and CI mode. However, deoxynivalenol, 3-acetyldeoxynivalenol, fusarenon-X and nivalenol were not detected in the extract, all of which are well known to be detected from scabby wheat.

Prune, Plum, and Nectarine as Hosts of Trichothecium roseum in California Orchards.

Trichothecium roseum (Pers.:Fr.) Link was frequently observed (up to 21%) on mummified peach (Prunus persica (L.) Batsch), nectarine (P. persica (L.) Batsch var. nectarina (Aiton) Maxim.), plum (P. salicina Lindl.), and prune (P. domestica L.) fruits in orchards during a 1995 to 1996 survey. Pink mold rot caused by T. roseum was also frequently observed (at about the 1 to 2% level) on a number of samples of prune fruit collected from commercial orchards in Glenn, Butte, Madera, Fresno, and Tulare counties in 1996, after storage at 4°C for 7 days and then 20°C for 4 days. Wounded and nonwounded prune (cv. French), plum (cv. Casselman), peach (cv. Fairtime), and nectarine (cv. Spring Bright) fruits were infected after inoculation with a drop (20 μl) of T. roseum suspension (5 × 105 conidia/ml). Characteristic pink sporulation covered the surface of most fruit 7 days after inoculation. Conidia of T. roseum completely covered all wounded and nonwounded prune fruit, sparsely on the wounded plum fruit, and densely on both wounded and nonwounded peach and nectarine fruits (lesion diameter = 1 to 7 cm) 2 weeks after inoculation. T. roseum sporulated more rapidly and better on the fruits that were contaminated with either Monilinia fructicola (G. Wint.) Honey, or a Cladosporium sp. Peach has been listed as a host of T. roseum (California Plant Disease Host Index, Part 1: Fruits and Nuts, A M. French, ed., 1987), but this is the first report on the pathogenicity of this fungus on prune, plum, and nectarine from California.

マスクメロン,トマト果実のバラ色カビ病とTyichothecium roseumによるトリコテシン産生

マスクメロン,トマト果実のバラ色カビ病とTyichothecium roseumによるトリコテシン産生

La semilla de maíz y su micoflora y germinación

Se evaluaron seis siembras de maíz opaco modificado desarrollados por el Centro Internacional de Mejoramiento de Maíz y Trigo (CIMMYT) y dos de maíz corriente local en Lajas e Isabela durante los meses de marzo a mayo en 1983. Las siembras fueron: i) las barbas inoculadas con el moho rosado 7 a 10 días después de la floración; ii) asperjadas con benomil dirigido a la mazorca en la misma fecha y 14 días después; iii) testigos sin tratar. Se anotó el número de granos con hongos visibles por mazorca y el porcentaje y el número de granos con hongos visibles por mazorca y el porcentaje de los granos dañados por insectos, mayormente el gusano de la mazorca de maíz (Heliothis zea) . En pruebas in vitro se determinó la viabilidad de las semillas (germinación) y la frecuencia de infecciones por hongo que sobrevivió el tratamienro de la semilla con cloro. En Lajas, 6.3% de las semillas se dañaron por insectos y 3.8 semillas por mazorca tenían hongos visibles (mohosos). La infección de semilla por Fusarium moniliforme llegó a un 53.5% y se asoció esta alta incidencia con la baja rasa de germinación de la semilla (68.6%). En Isabela, 8.3 semillas por mazorca tenían hongo y 0.1% de la semilla se dañó por gusanos. La infeccióon de semilla por F. moniliforme era baja (17.2%) y se asoció con una alta tasa de germinación (93.9%). Cephalosporium acremonium (32.8%) fue el hongo dominante en Isabela. Semillas infectadas con este hongo mostraron un vigor excepcional y no tenían las raíces descoloridas, lo cual ocurre con los otros hongos. En comparación con los testigos, la inoculación con el moho rosado aumentó la incidencia de infección en la semillas un 25% y más de 100% en Lajas e Isabela, respectivamente. La inoculación aumentó también el número de semillas con hongos. La aplicación de benomil a la mazorca no mostró una represión efectiva de hongos en la semilla y aumentó el daño por el gusano de la mazorca. El daño por insecto fue 4.4, 3.0 y 2.1% en los tratados con benomil, en los no tratados y en los inoculados, respectivamente. La aplicación de benomil a la semilla reprimió bien los hongos principales menos Curvularia lunata, que es una especie tolerante al benomil. La siembra de White H. E., tenía más semillas con hongos visibles que las otras. Se observó mejor calidad de la semilla en Amarillo Dentado QPM-2 y Mayorbela, pero no era una diferencia estadísticamente significativa.