Ampelomyces Research Articles

Podosphaera fusca에 의한 상추 흰가루병의 발생원인과 방제

Podosphaera fusca에 의한 상추 흰가루병은 상추 발생 병해중에서 가장 중요한 병해중 하나이다. 흰가루병 발생으로 상추재배가 피해로 인하여 재배자와 소비자를 위하여 좋은 품질의 상추를 생산하기 위한 방제법 개발이 필요하다. 상추 흰가루병 발생이 증가되는 원인은 계속적인 연중재배, 병든 식물체의 미제거, 흰가루병을 노균병으로 오인에 의한 부적절한 약제 처리 등이다. 경기도 수원시 근교에 상추 시설 재배 포장에서 미생물농약을 포함한 5가지 살균제에 대한 상추 흰가루병 방제 실험을 실시하였다. 상추 흰가루병이 발생 초기에 10일 간격 3회 분무 처리하여 최종 약제 처리 8일 후에 흰가루병 발생을 조사하였다. kresoxim-mothy SC, azoxystrobin SC, Ampelomyces quisqualis AQ94013 WP, Paenibacillus polymyxa AC-1 SC와 Bacillus Y 1336 WP를 처리한 흰가루병의 발생은 0.7%, 0.7%, 26.0%, 36.7% 각각 발생하였으며, 무처리는 55.3% 발병하였다. 상추유묘에 대하여 이들 약제의 기준량과 배량에서 약해는 없었다. Powdery mildew caused by Podosphaera fusca is one of the most important diseases in leafy lettuce (Lactuca sativa L.). Since the disease has been a threat to safe cultivation of leafy lettuce, its control methods have to develop to produce good quality of lettuce for farmer and consumer. Occurrence of lettuce powdery mildew is increasing more and more due to continuous cultivation of lettuce all through the year, non-removal of diseased plant parts of lettuce, spray of inadequate fungicides by mistaken acknowledge of lettuce powdery mildew for lettuce downy mildew, etc. The control effect of five fungicides against lettuce powdery mildew was examined in a plastic greenhouse located in Suwon. When fungicides were sprayed three times at 10 days-intervals in the early stage of occurrence of powdery mildew, the incidence of powdery mildew in the plants treated with kresoxim-methy SC, azoxystrobin SC, Ampelomyces quisqualis AQ94013 WP, Paenibacillus polymyxa AC-1 SC and Bacillus subtilis Y 1336 WP was 0.7%, 0.7%, 26.0%, 36.7% and 42.0%, respectively, whereas the incidence of non-treated control was 55.3% on eight days after final application. Phytotoxicity of five fungicides tested was not observed in lettuce seedling plants.

Ampelomyces quisqualis 94013을 이용한 오이 흰가루병 생물적 방제

Ampelomyces quisqualis 94013(AQ94013)이 오이 흰가루병의 생물적 방제를 위하여 효과적인 기생균으로 선발되었다. 온실에서 AQ94013의 포자현탁액을 <TEX>$5.0{\times}10^6/ml$</TEX> 또는 <TEX>$5.0{\times}10^7/ml$</TEX>를 예방적으로 경엽 살포하여 9일간 오이 흰가루병의 발생을 상당히 억제시켰다. 오이 흰가루병이 발생한 후에 AQ94013의 포자현탁액<TEX>$(5.0{times}10^6/ml)$</TEX>을 처리하였을 때에도 3일에서 7일내에 흰가루병을 효과적으로 억제시켰다. 오이재배 비닐하우스에서 AQ94013의 포자현탁액<TEX>$(5{\times}10^6/ml)$</TEX>을 7일 간격 3회 처리는 AQ94013의 포자현탁액의 10일 간격 2회 처리와 화학약제 훼나리몰유제를 2회 처리한 것 보다 오이 흰가루병 방제 효과가 높았다. 그러므로 AQ94013균주는 오이 흰가루병 생물적 방제을 위하여 유망한 미생물살균제로 개발할 필요가 있다고 판단되었다. An isolate of Ampelomyces quisqualis 94013(AQ94013) was selected as an effective parasite for biological control of cucumber powdery mildew. In the greenhouse, occurrence of cucumber powdery mildew was significantly suppressed for nine days by pre-treatment with <TEX>$5.0{\times}10^6/ml$</TEX> and <TEX>$5.0{\times}10^7/ml$</TEX> of conidial suspension of AQ94013. The disease was effectively controlled within three to seven days by post-treatment with the <TEX>$5.0{\times}10^6/ml-conidial$</TEX> suspension of AQ94013. When AQ94013 was treated at concentration of <TEX>$5{\times}10^6/ml$</TEX> three times at seven-day interval in the vinylhouse, the control effect was higher than that treated twice at ten-day interval and that treated with fenarimol twice. As the results, Ampelomyces quisqualis 94013 could be a prospective biofungicide for biological control of powdery mildew of cucumber.

흰가루병 생물적 방제용 중복기생균 Ampelomyces quisqualis 94013의 대량배양

An isolate of Ampelomyces quisqualis 94013(AQ94013) was selected as an effective agent for biological control against cucumber powdery mildew. In order to develop mass production technique, six cereal media made with barley, rice, mille and brown rice, sorghumand rice seed were tested. Among them, barley medium was the best for the growth and conidial production of AQ94013. Optimum temperature for the mass production of AQ94013 was and followed by and . Light radiation inhibited conidial production of AQ94013 since number of conidia formed on barely medium under continuous light or 12 hrs alternative light were much less than cultured in darkness. Tthe conidia produced on the medium at maintained the parasitic ability to Sphaerotheca fusca for 30 days. A culture method of AQ94013 in barley liquid medium with adding barely power(40 g/l) in darkness for five days at using a 30 l-fermenter was very effective for mass production of conidia.

Evaluation of biological control agents for managing cucurbit powdery mildew on greenhouse‐grown melon

An evaluation was made of the ability of two mycoparasite‐based products AQ10® (Ampelomyces quisqualis) and Mycotal® (Lecanicillium lecanii), as well as three strains of Bacillus subtilis, to manage powdery mildew disease, caused by Podosphaera fusca on melon seedlings maintained under different regimes of relative humidity and on plants grown under greenhouse conditions in Spain. In every case fungal and bacterial biocontrol agents (BCAs) performed better under conditions of high relative humidity (90–95% RH). In greenhouse experiments, the effectiveness of the mycoparasites to manage powdery mildew was absolutely dependent on mineral oil. The strains of B. subtilis provided disease control similar to that achieved with the mycoparasites or the fungicide azoxystrobin. Microscopic analysis showed the ability of these bacterial strains to efficiently colonize leaf surfaces and revealed the occurrence of antagonistic interactions between biological agents and P. fusca structures. These results confirmed the usefulness of these BCAs for managing powdery mildew on greenhouse‐grown cucurbits either as single products or as a component of integrated control programmes.

Integrating biocontrol agents in strawberry powdery mildew control strategies in high tunnel growing systems

Strawberry powdery mildew is a serious disease and its control is based on chemical fungicides. The efficacy of alternatives to chemical fungicides was evaluated and their integration into strategies against strawberry powdery mildew to reduce pesticide residues on fruits was also tested. Bicarbonates and mineral oils were poorly effective. Biocontrol agents (BCAs), like Ampelomyces quisqualis, Bacillus subtilis and Trichoderma harzianum T39, controlled the disease, but to a lesser extent than chemical fungicides. When BCAs were alternated with chemicals, a significant reduction of chemical fungicide residues was achieved while maintaining good powdery mildew control. None of the tested strategies increased populations of the pest Tetranychus urticae, nor had side effects on the beneficial predatory mite Amblyseius andersoni populations and, consequently, they can be regarded as safe for the ecological balance of arthropods in strawberry greenhouses.

Effect of colored shade nets on pepper powdery mildew (Leveillula taurica)

The effect of colored shade nets with different shade intensities and qualities of irradiation transmittance on pepper powdery mildew was tested in mini-plots and field experiments. Leaf coverage byLeveillula taurica and leaf shedding due to the disease were more severe in the shade, by up to 275% and 70%, respectively, than in the open field. Leaf coverage byL. taurica symptoms and leaf shedding from plants grown under 25% shade black nets were higher, by up to 70% and 180%, respectively, than under 40% shade nets. The color of the shade nets affected the intensity of photosynthetically active (PAR), ultra-violet (UV), blue, red and far red radiations, the UV/blue light ratio, and percent PAR and UV transmitted. The various nets suppressed the disease differently. Black, blue-silver, green and red nets were associated with lower levels of disease in the field experiments. The red net was also superior in the mini-plots. The other results from the mini-plots were not similar to those from the field, probably reflecting more intensive epidemic development in the mini-plots. No interaction between net type and cultivar was found when two cultivars were grown under the nets. Yield was higher under nets than in the open; nevertheless, the yield from plants grown under the 40% shade black net was not higher than that of the plants under the 25% black net, despite the significantly lower levels of disease at the higher shade intensity. B-quality pepper yield was significantly higher in the plots covered by 25% shade. Yield differences between the different colored nets were also not well correlated with disease levels, probably due to factors negating the direct effect of the nets on the plants and their yield. Implementation of either ‘friendly’ (Ampelomyces quisqualis AQ10/Trichoderma harzianum T39/ sulfur/ neem seed extract) or chemical (sulfur/ pyrifenox/ Polyoxin AL/ myclobutanil/ azoxystrobin) spray regimes successfully reduced disease severity under the different nets. There was no interaction between net type and spray regime. Thus, growing sweet pepper under shade nets results in increased yields and also in higher powdery mildew severity. Disease is negatively associated with the rate of shading and is variably affected by the quality of light filtered through the different colored shade nets.

Characterization of six polymorphic microsatellite loci from Ampelomyces quisqualis, intracellular mycoparasite and biocontrol agent of powdery mildew

Abstract Ampelomyces spp. are common intracellular mycoparasites of powdery mildews worldwide and a strain has been commercialized as a biocontrol agent against these plant pathogens. In light of recent genetic analyses revealing high internal transcribed spacer sequence variability among Ampelomyces strains on different host plant mildews, yet no sequence variability within the Malus strain, polymorphic microsatellites were required to permit biocontrol and ecological studies of the complex apple/apple mildew/Ampellomyces tritrophic interaction. For this purpose, described here are the primers to amplify six polymorphic microsatellite loci from Ampelomyces quisqualis isolated from mycelia of the apple powdery mildew fungus, Podosphaera leucotricha.

중복기생균 Ampelomices quisqualis 94013의 배양적 특성

Ampelomyces quisqualis 94013는 중복기생균으로 흰가루병 생물적 방제용 우수균주로 선발하여, 이 균의 효율적 이용을 위한 배양적 특성을 조사하였다. A. quisqualis 94013의 균사생육 적은은 <TEX>$26^{\circ}C$</TEX>이였으며, 균사생육 최적 pH는 6.5였다. 감자한천배지(PDA)배양시 광조건(형광등 12시간주기)보다는 암조건에서 더 많은 포자를 형성하였다. 이 균의 포자발아 온도범위는 <TEX>$10\~35^{\circ}C$</TEX>이고, 최적온도는 <TEX>$20^{\circ}C$</TEX>이였다. 포자발아는 <TEX>$24^{\circ}C$</TEX>에서 8시간 배양 후 시작되었으며, 포자발아율은 포자현탁액의 농도가 <TEX>$5{\times}10^7/ml$</TEX>보다 <TEX>$5{\times}10^5/ml$</TEX>나 <TEX>$5{\times}10^6/ml$</TEX>에서 높았다. 이 균은 탄소원으로는 dextrin을, 질소원으로는 neopepton을 가장 잘 이용하였다. Ampelomyces quisqualis 94013 (AQ94013), a hyperparasite, was selected as an effective biological control agent against cucumber powdery mildew. Optimal temperature for mycelial growth of AQ94013 was <TEX>$26^{\circ}C$</TEX>, and the optimal pH was 6.5. Conidia of AQ94013 were more Produced on potato dextrose agar (PDA) in darkness than under alternating cycles of 12 hr fluorescent light and 12 hr darkness. Temperature range for spore germination of the fungus was <TEX>$10\~35^{\circ}C$</TEX>, and optimal temperature was <TEX>$20^{\circ}C$</TEX>. Conidial germination of the fungus began 8 hr after incubation at <TEX>$24^{\circ}C$</TEX>. Germination rate of conidia at concentration of <TEX>$5{\times}10^5\;spores/ml\;and\;5{\times}10^6\;spores/ml$</TEX> was higher than at concentration of <TEX>$5{\times}10^7\;spores/ml$</TEX>. The best source of carbon and nitrogen for mycelial growth of the fungus were dextrin and neopeptone, respectively.

Ampelomyces quisqualis 94013의 오이 흰가루병균 기생에 영향을 미치는 환경조건과 기주범위

An isolate of Ampelomyces quisqualis 94013 was selected as an effective parasite for biological control against cucumber powdery mildew. Temperature range for the parasitism of A. quisqualis 94013 against cucumber powdery mildew was , and optimal temperature for that . In humidity of the greenhouse, parasitic ability of A. quisqualis 94013 against Sphaerotheca fusca was not good. Inoculation tests revealed that A. quisqualis 94013 can parasitize on six species of Sphaerotheca in the 12 crops and Ersiphe cichoracerum in tomato. As host rang of A. quisqualis 94013 was broad and it may be used effectively as a biocontrol agent for powdery mildew of 13 crops.

First Report of Powdery Mildew Caused by Erysiphe cichoracearum on Creeping Thistle (Cirsium arvense) in North America.

Creeping or Canada thistle (Cirsium arvense (L.) Scop.) is a perennial weed of Eurasian origin that arrived in North America as early as the 1700s (3). Spreading by seeds and rhizomes, it is now widely distributed in Canada, Alaska, and 40 other states. It is apparently absent from Texas, Oklahoma, Louisiana, Mississippi, Alabama, Georgia, Florida, and South Carolina (1). Powdery mildew is common on C. arvense in Europe, but it has never been observed in North America (4). In Europe and Asia, powdery mildew of C. arvense is caused by any one of the following fungi: Leveillula taurica, two species of Sphaerotheca, and varieties of Erysiphe cichoracearum and E. mayorii. Specimens of C. arvense infected with powdery mildew (deposited in the U.S. National Fungus Collections as BPI 843471) were collected in the fall of 2003 near Moscow, ID and in two areas in Oregon (the canyon of the Grande Ronde River and near the base of the Wallowa Mountains). Mycelium and cleistothecia were observed on stems and upper and lower surfaces of leaves. The mean diameter of the cleistothecia was 122 (±11.6) μm. Basally inserted, mycelioid appendages were hyaline or brown and varied considerably in length, but most were in the range of 80 to 120 μm. Asci averaged 58 (±5.5) μm × 35 (±4.1) μm in length and width, respectively. Each ascus bore two ascospores averaging 23 (±1.4) μm × 14 (±1.7) μm. Conidia averaged 30 (±3.0) μm × 14 (±0.8) μm. The specimens fit the description of E. cichoracearum DC. (2). Because the length/breadth ratio of conidia is greater than 2, the specimens could be further diagnosed as E. cichoracearum var. cichoracearum (2). Also noteworthy was the presence of the hyperparasitic Ampelomyces quisqualis Ces. ex Schlechtend. E. cichoracearum is thought to be a cosmopolitan powdery mildew of broad host range, but this concept is difficult to reconcile with the absence of mildew on North American populations of C. arvense for more than 200 years.

Effect of mycoparasitic fungi on the development of Sphaerotheca fusca in melon leaves

We evaluated the possibilities of exploitation of several mycoparasitic fungi in the biocontrol of cucurbit powdery mildew (Sphaerotheca fusca) in melon greenhouses. To simplify the screening, an in vitro biological control test on detached leaves of melon has been used and a detailed microscopic analysis of the interactions between mycoparasites and S. fusca conducted. In this context, the effect of mycoparasitic fungi on the formation of infection structures of S. fusca such as haustoria, conidia and conidiospores has been quantified. On the basis of the microscopic data, effect of mycoparasites on severity and incidence of cucurbit powdery mildew has been discussed. Our results show that, under controlled environmental conditions, Acremonium alternatum, Ampelomyces quisqualis and especially Lecanicillium lecanii, when applied in early stages of infection, were able to significantly reduce cucurbit powdery mildew symptoms and S. fusca development on melon leaves. These results indicate that these mycoparasites are promising candidates for the biocontrol of cucurbit powdery mildew in melon greenhouses.

Preliminary evaluation of the effect of Ampelomyces quisqualis on the degree of plant infestation with selected Erysiphales species proposed as potential bioindicators

In the year 2000 Ampelomyces quisqualis was noted, with various intensity, in north-eastern Poland on different species of Erysiphales selected as potential bioindicators of urban pollution. The results of observation of Erysiphe sordida (on Plantago major), Sphaeroteca erigerontis-canadensis (on Taraxacum officinale) and Microsphaera hypophylla (on Quercus robur) – susceptible species, and Microsphaera palczewskii (on Caragana arborescens) – a resistant species, suggest that A. quisqualis shows affinity to some hosts regardless of their individual reactions to the level and range of anthropopressure. It clearly prefers the genera: Erysiphe and Sphaerotheca. Its effect on the degree of host plant infestation with powdery mildew under natural conditions seems insignificant.

Distribution of cucurbit powdery mildew species in the Czech Republic

The occurrence of Erysiphe cichoracearum (Ec) and Sphaerotheca fuliginea (Sf), causal agents of cucurbit powdery mildew&lt;br /&gt;in the Czech Republic (CR) was studied in the period of 1995–2001. Nearly 800 leaf samples with disease symptoms&lt;br /&gt;were microscopically examined. Ec is the predominating species, detected on 98% of locations. It was accompanied by Sf&lt;br /&gt;on 24% of locations. The occurrence of Sf as the only powdery mildew species was proved on 2% of locations. Recent&lt;br /&gt;occurrence of Sf in the CR corresponds with data on Sf fast spreading and prevailing on cucurbits in West and South&lt;br /&gt;Europe. However, Ec is the strongly predominating powdery mildew species largely distributed throughout the country.&lt;br /&gt;The hyperparasitic fungus Ampelomyces quisqualis was detected on 30% of samples.

AQ10 Biofungicide Combined with Chemical Fungicides or AddQ Spray Adjuvant for Control of Cucurbit Powdery Mildew in Detached Leaf Culture.

The biofungicide AQ10, a pelleted formulation of conidia of Ampelomyces quisqualis, did not significantly reduce the size of colonies of the cucurbit powdery mildew (Podosphaera xanthii) in detached squash leaf culture but did reduce the amount of inoculum produced by each colony. No significant reduction in colonization of powdery mildew colonies by AQ10 was observed when it was sprayed in conjunction with the fungicides myclobutanil at 10 μg/ml or triadimefon at 100 μg/ml, suggesting that it is not sensitive to the fungicides at these concentrations. The spray adjuvant AddQ did not increase percent colonization by A. quisqualis but reduced the size of mildew colonies when used alone or with AQ10.

Molecular studies on intraspecific diversity and phylogenetic position of Coniothyrium minitans

Simple sequence repeat (SSR)±PCR amplification using a microsatellite primer (GACA)% and ribosomal RNA gene sequencing were used to examine the intraspecific diversity in the mycoparasite Coniothyrium minitans based on 48 strains, representing eight colony types, from 17 countries world-wide. Coniothyrium cerealis, C. fuckelii and C. sporulosum were used for interspecific comparison. The SSR±PCR technique revealed a relatively low level of polymorphism within C. minitans but did allow some differentiation between strains. While there was no relationship between SSR±PCR profiles and colony type, there was some limited correlation between these profiles and country of origin. Sequences of the ITS 1 and ITS 2 regions and the 5±8S gene of rRNA genes were identical in all twenty-four strains of C. minitans examined irrespective of colony type and origin. These results indicate that C. minitans is genetically not very variable despite phenotypic differences. ITS and 5±8S rRNA gene sequence analyses showed that C. minitans had similarities of 94% with C. fuckelii and C. sporulosum (which were identical to each other) and only 64% with C. cerealis. Database searches failed to show any similarity with the ITS 1 sequence for C. minitans although the 5±8S rRNA gene and ITS 2 sequences revealed an 87% similarity with Aporospora terricola. The ITS sequence including the 5±8S rRNA gene sequence of Coniothyrium cerealis showed 91% similarity to Phaeosphaeria microscopica. Phylogenetic analyses using database information suggest that C. minitans, C. sporulosum, C. fuckelii and A. terricola cluster in one clade, grouping with Helminthosporium species and 'Leptosphaeria' bicolor. Coniothyrium cerealis grouped with Ampelomyces quisqualis and formed a major cluster with members of the Phaeosphaeriacae and Phaeosphaeria microscopica.

Biological control in greenhouse systems.

The controlled environment of greenhouses, the high value of the crops, and the limited number of registered fungicides offer a unique niche for the biological control of plant diseases. During the past ten years, over 80 biocontrol products have been marketed worldwide. A large percentage of these have been developed for greenhouse crops. Products to control soilborne pathogens such as Sclerotinia, Pythium, Rhizoctonia and Fusarium include Coniothyrium minitans, species of Gliocladium, Trichoderma, Streptomyces, and Bacillus, and nonpathogenic Fusarium. Products containing Trichoderma, Ampelomyces quisqualis, Bacillus, and Ulocladium are being developed to control the primary foliar diseases, Botrytis and powdery mildew. The development of Pseudomonas for the control of Pythium diseases in hydroponics and Pseudozyma flocculosa for the control of powdery mildew by two Canadian research programs is presented. In the future, biological control of diseases in greenhouses could predominate over chemical pesticides, in the same way that biological control of greenhouse insects predominates in the United Kingdom. The limitations in formulation, registration, and commercialization are discussed, along with suggested future research priorities.

Sequence analysis of the chitin synthase A gene of the Dutch elm pathogen Ophiostoma novo-ulmi indicates a close association with the human pathogen Sporothrix schenckii

Degenerate oligonucleotide primers were designed according to conserved regions of the chitin synthase gene family and used to amplify a 621 basepair (bp) fragment from genomic DNA of Ophiostoma novo-ulmi, the causal agent of Dutch elm disease. The amplification product was used as a hybridization probe to screen a library of genomic DNA sequences and to retrieve a full-length chitin synthase gene (chsA). The putative coding region of the gene was 2619 bp long, lacked introns, and encoded a polypeptide of 873 amino acids. Based on the similarity of the predicted amino acid sequence to the full-length chsC gene of Aspergillus nidulans and chsA gene of Ampelomyces quisqualis, the O. novo-ulmi chsA was classified as a Class I chitin synthase. The phylogenies constructed, according to a subregion of all available chitin synthases, showed that O. novo-ulmi consistently clustered most closely with the human pathogen Sporothrix schenckii, recently classified as a member of the mitosporic Ophiostomataceae. Disruption of the chsA gene locus had no obvious effects on the growth or morphology of the fungus.

The Mycoparasite Ampelomyces quisqualis Expresses exgA Encoding an exo-β-1,3-Glucanase in Culture and During Mycoparasitism

ABSTRACT Ampelomyces quisqualis, a mycoparasite of fungi causing powdery mildews, exhibited high levels of extracellular exo-beta-1,3-glucanase activity in culture compared with Neurospora crassa and Gliocladium roseum. A. quisqualis culture filtrates affected powdery mildew caused by Sphaerotheca fusca in a manner indicative of cell wall degradation, as determined by microscopic examination. A gene encoding an exo-beta-1,3-glucanase in A. quisqualis, designated exgA, was isolated and sequenced. The predicted polypeptide deduced from exgA had 46, 42, and 30% identity with amino acid sequences of Trichoderma harzianum exo-beta-1,3-glucanase and Cochliobolus carbonum EXG1 (both encoding exo-beta-1,3-glucanase) and T. harzianum bng13.1 (encoding an endo-beta-1,3-glucanase), respectively. The exgA gene had a predicted molecular mass of 84 kDa and a pI of 4.79. The gene was expressed during the late stages of growth in culture, and transcription was induced by fungal cell wall components. Transcript levels for exgA were present during late stages of hyperpar-asitism and were abundant along A. quisqualis mycelium and were slightly less abundant in A. quisqualis pycnidia.

Evaluation of biocompatible products for managing cucurbit powdery mildew

The biocompatible products AQ10 (hyperparasitic fungus Ampelomyces quisqualis), JMS Stylet-Oil (medium viscosity mineral oil), M-Pede (potassium salts of fatty acids) and Kaligreen (82% potassium bicarbonate) suppressed powdery mildew ( Sphaerotheca fusca) on winter squash, muskmelon, and pumpkin and increased yield compared with nontreated plants under field conditions. Applications were started after disease detection. JMS Stylet-Oil most effectively controlled powdery mildew. However, these products did not provide the degree of full-season control or yield increase obtained with the conventional fungicide program of Bravo (chlorothalonil) plus Nova (myclobutanil). For example, in muskmelon on 17 August 1995, 7 days after the third application, powdery mildew severity on upper and lower (under) leaf surfaces was 66 and 80% for untreated, 3 and 13% for Bravo plus Nova, 43 and 44% for JMS Stylet-Oil, 38 and 65% for AQ10, and 53 and 65% for Kaligreen, respectively. Yield (ton/ha) was 22.8, 44.2, 36.4, 40.6, and 38.5, respectively. Sucrose content was 3.5%, 6.6%, 4.6%, 3.2%, and 4.0%, respectively.

Ribosomal DNA internal transcribed spacer sequences do not support the species status of Ampelomyces quisqualis, a hyperparasite of powdery mildew fungi.

Phylogenetic relationships among Ampelomyces isolates, pycnidial hyperparasites and biological control agents of powdery mildews, were inferred from internal transcribed spacer (ITS) sequences of the ribosomal DNA (rDNA). Currently, these hyperparasites are considered to be a single species, A. quisqualis, despite observed morphological and cultural differences. Ten Ampelomyces isolates, representing seven previously defined ITS RFLP groups, were sequenced and analyzed. Sequence-divergence values among isolates belonging to different RFLP groups ranged from 4.3 to 22.4%, suggesting that these isolates may represent different taxa. When Ampelomyces ITS sequences were analyzed by cladistic methods with the sequences of other ascomycetous fungi, they formed two lineages in the Dothideales. Slow-growing Ampelomyces isolates formed a clade with Leptosphaeria microscopica and L. nodorum, whereas fast-growing Ampelomyces isolates formed a clade with Epicoccum nigrum. Sequence-divergence values between these two clades ranged from 17.3 to 22.4%, suggesting that the taxa in the two clades are not closely related and possibly not congeneric. The data presented here indicate that the identification of 'A. quisqualis' isolates used in biological control experiments should be re-evaluated.