The fungal flora of soft fruits in relation to storage and spoilage

The fungal population of freshly harvested strawberries, raspberries and blackberries was studied throughout the fruiting seasons and the relative importance of fungi responsible for spoilage of stored fruit from different harvest dates was assessed. Botrytis cinerea, Cladosporium spp., Penicillium spp., Aureobasidium pullulans and Mucor spp. were consistently present on all three fruits while Colletotrichum gloeosporioides and Didymella applanata were prevalent on raspberries only and Epicoccum purpurascens and Alternaria spp. on blackberries only. Botrytis cinerea and Mucor mucedo were the predominant spoilage organisms of all three fruits, although the relative importance of the two fungi changed as the season progressed, especially for strawberries. Rhizopus stolonifer, Cladosporium spp., Penicillium spp. and Colletotrichum gloeosporioides were only of minor importance as spoilage organisms.     

Effect of pre-harvest fungicides on the spoilage of soft fruit after harvest

In the 1972 season, Elvaron and Benlate reduced the count of Botrytis cinerea, Cladosporium spp., Penicillium spp. and Aureobasidiutn pullulans on strawberry and raspberry fruits during the first 2 wk of the season, but not subsequently. No such reduction was recorded for Hainesia lythri (strawberries only), Phoma state of Didymella applanata (raspberries only), Mucor spp., and Rhizopus spp. Similar results were obtained in 1973. In the first half of either season, both fungicides decreased the rate of fungal spoilage of stored fruit (except for Benlate in the 1973 season), although in the latter part of the season, there was little difference in the incidence of fungal spoilage between sprayed and unsprayed fruit. Both fungicides, however, reduced the development of B. cinerea (and Cladosporium spp. on raspberries) on stored fruit irrespective of season or harvest date except for Benlate in the 1973 season where Benlate-resistant strains of the fungi developed on the fruit. The failure of either fungicide to reduce fungal spoilage in the latter part of the harvesting season was due to the development of Phycomycetes, particularly Mucor mucedo and to a lesser extent Rhizopus stolonifer and R. sexualis, except where Benlate-resistant strains of B. cinerea and Cladosporium spp. were present.     

Biofungicides as alternative to synthetic fungicide control of grey mould (Botrytis cinerea) – prospects and challenges

Botrytis cinerea is one of the most destructive pathogens of ve?getables and fruits both in the field and storage. There have been several research activities focused on developing biocontrol strategies for the pathogen due to its resistance to the commonly used synthetic fungicides. Additionally, concerns have been raised over residual effect of current synthetic fungicides used for its control. Most of these research activities have focused on Trichoderma spp., Ulocladium spp., Bacillus subtilis, plant extracts and their essential oils with some commercial products available on the market for the control of B. cinerea disease. This review summarises some of the current published information on the use of biocontrol agents and plant-based compounds for B. cinerea control. Some limitations and future prospects were also mentioned.     

Resistenz verschiedener Kultur- und Wildtomatenpflanzen (Lycopersicon spp.) gegenüber Botrytis cinerea Pers.

Resistance of different cultivated and wild tomato plants (Lycopersicon spp.) to Botrytis cinerea Pers. 20 provenances of different cultivated and wild tomato plants (Lycopersicon spp.) were screened for resistance to Botrytis cinerea Pers. using an in vitro-leaf necrosis test. The Botrytis resistance decreased with increasing age of the leaves corresponding to their insertion height (relative youth resistance respectively senescence susceptibility). The 6 B. cinerea-isolates used for inoculation differed significantly in virulence. With increasing inoculum age a virulence reduction of the various B. cinerea-isolates occurred. Within the investigated test plant collection 2 wild species –L. columbianum and L. hirsutum– proved to be resistant in each stage of development to all B. cinerea-isolates and additionally showed field resistance.     

<i>In vitro</i> evaluation of antifungal activity of Agave (<i>Agave scabra</i>, Salm Dyck) extracts against post-harvest mushrooms

The agricultural sector, and particularly the horticultural production, has a singular importance in agriculture, considering that it ranks second on agricultural products, nationally and worldwide. Fungal diseases are one of the major causes of vegetable loss during storage, reducing their nutritional value, quality and sale price. Vegetables are usually exposed to diverse treatments with chemical products before storage; as a result, fungal populations develop an increased resistance over time becoming more difficult to control. Because of this, research efforts toward finding more suitable chemicals to control fungal diseases are needed. Natural extracts may be an alternative solve this problem. In the present investigation the fungicidal activity of aqueous and ethanol extracts of Agave scabra was evaluated on the growth of Botrytis cinerea, Mucor sp., Aspergillus niger, Fusarium sp. and Penicillium sp., whose strains were isolated from potato and tomato. To assess their effects, the agar-dilution and agar-well techniques were performed. The ethanol extract was more effective against Botrytis cinerea and Mucor sp. when the agar-well method was used. However, when using the agar-dilution method the ethanol extract of Agave scabra inhibited the growth of Botrytis cinerea, Mucor sp. and Penicillium sp.     

Decay of Sclerotia of Botrytis cinerea by Trichoderma spp. at Low Temperatures

In vitro, tests were conducted at 10°C and 5°C against sclerotia of Botrytis cinerea with 58 isolates of Trichoderma spp., highly antagonistic at 24°C but differing in their cold tolerance. Some isolates macerated and colonized sclerotia even at 5 °C. With 19 isolates of Trichoderma spp. less than 10 % of the sclerotia remained viable after 42 d at 5 °C. Conidia ol some Trichoderma spp. germinated at 5 °C within a few days and reached germination rates higher than 80 %. It seems to be feasible to use selected isolates of Trichoderma spp. for biological control of sclerotia of ß. cinerea also during the colder season.     

Negative cross-resistance between benomyl and MDPC in British isolates of Botrytis cinerea, Pseudocercosporella herpotrichoides and Verticillium fungicola var. fungicola

Fifteen isolates of Pseudocercosporella herpotrichoides, four isolates of Botrytis cinerea and four isolates of Verticillium fungicola var. fungicola were examined on potato dextrose agar amended with benomyl or methyl N-(3, 5-dichlorophenyl)-carbamate (MDPC). Negatively correlated cross-resistance was clearly demonstrated with the isolates of P. herpotrichoides and B. cinerea. There were indications that the same phenomenon might also operate with the isolates of V. fungicola var. fungicola.     

Screening tomato-associated bacteria for biological control of grey mold on tomato

Aiming at discovering effective biocontrol agents (BCAs) against grey mold on tomato caused by Botrytis cinerea Pers., we selected 819 bacterial isolates from the surface as well as the interior of the roots, stems, and leaves of tomato plants grown in B. cinerea-infested fields. In a dual-culture assay, 116 isolates (14.16%) showed antagonism against B. cinerea and fewer ones against five additional tomato-associated fungal pathogens – Pythium ultimum, Phytophthora capsici, Fusarium oxysporum f. sp. lycopersici, Sclerotinia sclerotiorum and Ralstonia solanacearum. Thirty-one isolates with antagonism to B. cinerea and at least one of the five additional pathogens were assessed for their efficacy in controlling grey mold on tomato in a greenhouse test. Thirteen of them attained the efficacy over 50% and were subjected to the second greenhouse test, in which 12 isolates consistently accomplished the biocontrol efficacy over 50%, with isolates ABc28 and ABc22 achieving the efficacy of 66.71% and 64.90%, respectively. Under greenhouse conditions, the above two as well as isolates ABc2, ABc11 and ABc17 increased tomato biomass by more than 20% in comparison with the control. The 12 antagonistic isolates accomplishing the biocontrol efficacy over 50% in both greenhouse tests were considered potential BCAs against grey mold, which were identified as Pseudomonas spp., Pantoea spp., Bacillus spp. and Chryseobacterium spp. Ten of them were found to produce at least one of the three hydrolytic enzymes (protease, cellulase and chitinase) and/or siderophore, which might be involved in their mechanisms of suppressing the disease. Based on the origin of these 12 strains, the leaf tissue, especially the leaf interior, of tomato plants grown in a B. cinerea-infested field appears to be a good source of potential BCAs against grey mold.     

Effect of fungicides on the mycelial growth of soft fruit spoilage fungi

The in vitro activity of a range of fungicides was tested on strains of Botrytis cinerea, Mucor mucedo, Rhizopus stolonifer, and R. sexualis. Di-chlofluanid and dichloran were more active than the other fungicides against all of the strains of B. cinerea, while dichloran, dichlorophen and the dithiocarbamate fungicides were the most active against the Rhizopus species. Only dichlorophen and thiram markedly inhibited the growth of M. mucedo.     

The effect of volatile and gaseous metabolites of swelling seeds on germination of fungal spores

Effects of volatile and gaseous metabolites of swelling seeds of pea, bean, wheat, corn, cucumber, tomato, lentil, carrot, red pepper and lettuce on germination of spores of five genera of fungi were found to depend rather on the fungal than on the plant genus. Germination of spores ofBotrytis cinerea, Mucor racemosus andTrichoderma viride was most severely inhibited. Spores ofVerticillium dahliae were less sensitive and germination of spores ofFusarium oxysporum was inhibited only in two cases. On the other hand, exudates of pea and bean stimulated germination of spores ofFusarium oxysporum. Also spores ofTrichoderma viride germinated better in an atmosphere enriched with exuded metabolites of swelling lettuce seeds. When carbon dioxide produced by the swelling seeds was absorbed in potassium hydroxide, spores ofTrichoderma viride andVerticillium dahliae did not germinate at all, the inhibitory effects of volatile and gaseous exudates on germination of spores ofMucor racemosus were accentuated, and also the percentage of germinated spores ofFusarium oxysporum decreased. Germination of spores ofBotrytis cinerea was not influenced. Absorption of volatile and gaseous metabolites in a solution of potassium permanganate decreased in most cases their inhibitory effects, particularly inBotrytis cinerea.     

解淀粉芽孢杆菌B15抑菌物质对葡萄灰霉病灰葡萄孢的抑菌机理

【目的】利用荧光显微镜和激光共聚焦扫描显微镜技术初步探讨解淀粉芽孢杆菌(Bacillus amyloquefaciens)B15菌株发酵液中的抑菌混合物质伊枯草菌素A(iturin A)和芬芥素(fengycin)对葡萄灰霉病病原菌灰葡萄孢(Botrytis cinerea)的抑菌机理。【方法】采用琼脂稀释法讨论解淀粉芽孢杆菌B15发酵液对灰葡萄孢的抑菌活性。利用台盼蓝(trypan blue)染色、4′,6-二脒基-2-苯基吲哚(DAPI)、双氢罗丹明123(DHR123)、钙离子探针fluo-3/am和Annexin V-PI探针染色来观察解淀粉芽孢杆菌B15发酵液对灰葡萄孢细胞膜和菌丝形态、细胞核、活性氧、钙离子和磷脂酰丝氨酸层的影响。【结果】抑菌活性实验发现解淀粉芽孢杆菌B15发酵液对灰葡萄孢具有良好抑菌效果。荧光显微镜台盼蓝染色观察发现,经B15发酵液处理过的灰葡萄孢出现菌丝畸形、菌丝体粗大、尖端肿胀并被染成蓝色和明显的液泡化现象。同时未在处理组中观察到细胞内容物泄漏,说明处理组菌丝细胞膜未发生破损。该结果表明在此次试验中,B15发酵液中的抑菌有效物质不以破损细胞膜的方式直接导致灰葡萄孢的死亡。激光共聚焦显微镜观察结果发现,处理组的灰葡萄孢菌丝出现典型的细胞凋亡现象、染色质固缩、细胞核裂解、磷脂酰丝氨酸层外翻、活性氧和钙离子积累。【结论】该实验表明解淀粉芽孢杆菌B15发酵液以诱导细胞凋亡的形式来抑制灰葡萄孢菌丝的生长。     

The diseases of ornamental plants caused by aphelenchoides ritzemabosi in association with fungi

A great importance of Aphelenchoides ritzemahosi in a disease of Callistephus chinensis, Chrysanthemum spp. and Zinnia violaceae was found. In the disease process caused by the nematode, fungi of different parasitic abilities participated, e.g., Septoria chrysanthemella frequently attacked varieties of the genus Chrysanthemum, whereas Fusarium spp. affected C. chinensis. Longer rainy periods stimulated the development of higher epidemics of gray mold. Aphelenchoides ritzemabosi occasionally fed on hyphae that along with metabolities excreted into a medium differently influenced the nematode. Aphelenchoides ritzemabosi survived up to some years in a plant material. The phylloplane mycoflora population increased quantitatively and qualitatively when the plants aged. Filamentous fungi increased the necrosis of plants affected by the nematode. Fungi testing Botrytis cinerea showed a different potential of an antagonistic influence. Gonatobotrys simplex parasitized on Alternaria zinniae.     

嗜线虫致病杆菌抑制灰葡萄孢的效应

[背景] 灰葡萄孢（Botrytis cinerea）是引起葡萄采后病害的主要病原菌之一,严重影响葡萄的贮期和品质,给葡萄产业带来极大损失。利用拮抗微生物抑制采后病原菌生长已逐渐成为防治葡萄采后灰霉病的重要手段。[目的] 利用昆虫病原线虫共生细菌广谱高效的抑菌特性,从现有共生细菌资源中筛选对灰葡萄孢具有高拮抗作用的菌株,为葡萄采后灰霉病的抑制提供新的材料和研究方向。[方法] 通过平板对峙培养法和菌丝生长速率法分离筛选拮抗共生细菌,并对优选的高效拮抗共生细菌进行16S rRNA基因序列进化分析,采用扫描电镜观察其对灰葡萄孢菌丝生长的影响,利用损伤接种法对红地球葡萄防治效果进行验证。[结果] 初步分离筛选共获得9株拮抗菌,复筛与复测得到一株抑菌效果显著的共生细菌（命名为ALL）,经进化分析其为嗜线虫致病杆菌（Xenorhabdus nematophila）,其16S rRNA基因序列的Genbank登录号为MW488402,与菌株Xenorhabdus nematophi la NC116聚于同一分支,相似性达99.79%。扫描电镜观察该菌株导致灰葡萄孢菌丝扭曲变形、表面皱缩、失水塌陷,该菌株发酵（36 h）上清液浓度为1%时对灰葡萄孢菌丝抑制率达44.5%。在葡萄常温防效实验中,与对照组比较,ALL菌株发酵上清液对灰霉菌防治效果较好,3 d后防效为63.50%。[结论] 本研究应用昆虫病原线虫共生细菌生物防治葡萄贮期灰霉病,筛选出一株高效拮抗灰葡萄孢的昆虫病原线虫共生细菌,而且其上清液对灰葡萄孢具有良好的抑制效果,为生物防治贮期葡萄灰霉病提供了新的生物材料和相关研究基础。     

Effect of Gamma Irradiation on Strawberries as a Means of Extending Its Shelf-Life and Lethal Dose of Botrytis cinerea

Effectiveness of γ-irradiation as a protective means against post-harvest decay in ‘Donner’ strawberries produced in Gumma Pref., Japan, was investigated. In case when strawberries were kept at 23°C, 10-% infection due to saprophytic fungi, such as Botrytis cinerea, Rhizopus and Penicillium, was found 3 days after zero-kiloroentgen (kR) irradiation, 4 days after 100-kR irradiation, and 5 to 6 days after 200-kR irradiation. For the purpose of wrap-film, ordinary cellophane was found to be more favorable than water-proof cellophane at room temperature.

Main saprophytic fungus of ‘Donner’ berries was isolated and identified to be Botrytis cinerea Persoon. Lethal dose of B. cinerea was determined from its survival curve.     

Field evaluations of systemic fungicides and derivatives of dithiocarbamic acid for the control of clubroot

Strains of Botrytis cinerea and Mucor mucedo germinated and grew over the range 0.25^°C. There were differences in germination rates and growth rates between strains of B. cinerea at any given temperature. Five of the benomyl-resistant strains germinated and grew more slowly than any of the other benomyl-resistant or benomyl-sensitive strains of B. cinerea tested. Strains of Rhizopus stolonifer and R. sexualis germinated and grew between 5 and 25^°C, and although some spores germinated at 2^°C, subsequent growth of the germ tubes and growth from a mycelial inoculum did not occur. Neither species germinated or grew at o^°C. The effect of temperature on mycelial growth in vitro was consistent with the ability of the strains of the four species to infect strawberry fruits.     

Activité Fongicide du N-cetyl N,N,N-triméthylammonium Contre Botrytis cinerea Pers.

Fungicidal activity of N-cetyl N,N,N-trimethyl ammonium chloride to Botrytis cinerea Pers. Grey mould of grapes caused by Botrytis cinerea is the most important phytopatho-logical problem in swiss vineyards, since the appearance of resistant strains to dicarboxi-mides. Research for new chemicals is necessary. One compound, a cationic surfactant, the N-cetyl N,N,N-trimethyl ammonium chloride (CTAC), is very active in vitro against Botrytis cinerea. This product disturbs lethally the plasma membrane of conidia.     

Transformation of Terpenoids in Grape Must by Botrytis cinerea

Experiments were done to investigate the volatile components in botrytized grape must and transformation of terpenoids in terpene-supplemented grape must by Botrytis cinerea. Twenty-eight compounds were identified in the volatile concentrate of botrytized must with a combined gas chromatograph-mass spectrometer. No terpenoids were detected in the concentrate. Linalool or terpinen-4-ol decreased a lot when Botrytis cinerea was cultured in the must with these terpenes for 15 days. In linalool-supplemented botrytized must 9 identified and 3 unidentified terpenes were found, while only geranial was detected in terpinen-4-ol-supplemented botrytized must. Botrytis cinerea did not produce terpenoid in grape must without terpenes, but transformed linalool added to grape must into some other monoterpenes.     

Botrytis cinerea: Activité Antifongique dans les Jeunes Grappes de Vitis vinifera, Varieté Gamay

Botrytis cinerea: fungicidal activity in young grape berries of Vitis vinifera (Gamay) Extracts of young grape berries of Vitis vinifera (Gamay) inhibit the germination of conidia of Botrytis cinerea. This inhibitory activity is present in extracts obtained from clusters at bloom stage and is maintained until a developmental stage close to the maturity. These extracts ruptured the cellular membranes.     

The toolbox of Trichoderma spp. in the biocontrol of Botrytis cinerea disease

Botrytis cinerea is a necrotrophic fungal pathogen causing disease in many plant species, leading to economically important crop losses. So far, fungicides have been widely used to control this pathogen. However, in addition to their detrimental effects on the environment and potential risks for human health, increasing fungicide resistance has been observed in the B. cinerea population. Biological control, that is the application of microbial organisms to reduce disease, has gained importance as an alternative or complementary approach to fungicides. In this respect, the genus Trichoderma constitutes a promising pool of organisms with potential for B. cinerea control. In the first part of this article, we review the specific mechanisms involved in the direct interaction between the two fungi, including mycoparasitism, the production of antimicrobial compounds and enzymes (collectively called antagonism), and competition for nutrients and space. In addition, biocontrol has also been observed when Trichoderma is physically separated from the pathogen, thus implying an indirect systemic plant defence response. Therefore, in the second part, we describe the consecutive steps leading to induced systemic resistance (ISR), starting with the initial Trichoderma–plant interaction and followed by the activation of downstream signal transduction pathways and, ultimately, the defence response resulting in ISR (ISR‐prime phase). Finally, we discuss the ISR‐boost phase, representing the effect of ISR priming by Trichoderma spp. on plant responses after additional challenge with B. cinerea.