White rust of <Emphasis Type="Italic">Ipomoea</Emphasis> caused by <Emphasis Type="Italic">Albugo ipomoeae-panduratae</Emphasis> and <Emphasis Type="Italic">A. ipomoeae-hardwickii</Emphasis> and their host specificity

In some areas of Japan, yellow spots with white pustules on leaves, stems, petioles, peduncles and calyces were found on Ipomoea nil, I. triloba, I. lacunosa and I. hederacea var. integriuscula. We demonstrated that the diseases on I. nil, I. triloba and I. lacunosa were caused by host-specific strains of Albugo ipomoeae-panduratae and defined three forma speciales of the fungus, respectively, for the three Ipomoea species: “f. sp. nile”, “f. sp. trilobae” and “f. sp. lacunosae”. Because the diseases were new to Japan, we coined the Japanese name “shirosabi-byo”, which means white rust. We also showed that the disease on I. hederacea var. integriuscula was caused by A. ipomoeae-hardwickii. We named this new disease “white rust (shirosabi-byo in Japanese)”.     

Potential inhibitors against <Emphasis Type="Italic">Sclerotinia sclerotiorum</Emphasis>, produced by the fungus <Emphasis Type="Italic">Myrothecium</Emphasis> sp. associated with the marine sponge <Emphasis Type="Italic">Axinella</Emphasis> sp.

Sclerotinia sclerotiorum is a worldwide ascomycete fungal plant pathogen, which causes enormous yield losses on major economic crops such as crucifers, grain legumes and several other plant families. The objective of this research was to isolate and characterise some bioactive products from cultures of fungi associated with the marine sponge Axinella sp. In total, nine fungal isolates were obtained from the marine sponge Axinella sp. collected from the South China Sea. A group of test strains, including two G⁺ strains (Bacillus subtilis and Staphylococcus aureus), two G⁻ strains (Escherichia coli and Pseudomonas aeruginosa) and three fungi including two plant pathogenic fungi Sclerotinia sclerotiorum and Magnaporthe grisea and Saccharomyces cerevisiae, were employed as the indicator organisms for bioactivity screening. Using antagonistic tests and bioactive screening of the ethyl acetate (EtOAc) extracts of the corresponding cultures, fungal isolate JS9 showed the stronger efficacy against the test indicator strains, especially the indicator fungal pathogens. Isolate JS9 was further identified as Myrothecium sp. by a combination of morphological features and 18S rDNA BLAST on GenBank. Two macrocyclic trichothecenes, roridin A (compound 1) and roridin D (compound 2) were purified by tracking the activity of the EtOAc extract fractions and characterised with spectral analyses including MS, ¹H-NMR, ¹³C-NMR and disortionless enhancement by polarization transfer (DEPT). In vitro antifungal tests showed that the two macrocyclic trichothecenes were bioactive against S. cerevisiae, M. grisea and S. sclerotiorum with minimal inhibitory concentrations of 31.25, 125 and 31.25 μg ml⁻¹ for roridin A, and 62.5, 250 and 31.25 μg ml⁻¹ for roridin D, respectively. The present investigation demonstrated that two antifungal trichothecenes including roridin A and roridin D produced by the fungus Myrothecium sp. isolated from the marine sponge Axinella sp. could be potential inhibitors against the plant pathogen S. sclerotiorum. Lian Wu Xie and Shu Mei Jiang contributed equally to this work.     

Anthracnose of Christmas rose caused by <Emphasis Type="Italic">Colletotrichum</Emphasis> sp.

Leaf spots were found on Christmas rose (Helleborus niger) in Yamagata Prefecture, Japan, in October 2006. The morphology of the causal fungus was very close to that of Colletotrichum truncatum. Classifying the species from the sequences of the internal transcribed spacer regions of ribosomal DNA was inconclusive, and the isolates were identified only as Colletotrichum sp. Artificial inoculation confirmed the pathogenicity of isolates to the host plant and some legumes. We propose the name anthracnose of Christmas rose for this disease by Colletotrichum sp.     

Genetic variation among <Emphasis Type="Italic">Fusarium</Emphasis> isolates from onion,and resistance to <Emphasis Type="Italic">Fusarium</Emphasis> basal rot in related <Emphasis Type="Italic">Allium</Emphasis> species

The aim of this research was to study levels of resistance to Fusarium basal rot in onion cultivars and related Allium species, by using genetically different Fusarium isolates. In order to select genetically different isolates for disease testing, a collection of 61 Fusarium isolates, 43 of them from onion (Allium cepa), was analysed using amplified fragment length polymorphism (AFLP) markers. Onion isolates were collected in The Netherlands (15 isolates) and Uruguay (9 isolates), and received from other countries and fungal collections (19 isolates). From these isolates, 29 were identified as F. oxysporum, 10 as F. proliferatum, whereas the remaining four isolates belonged to F. avenaceum and F. culmorum. The taxonomic status of the species was confirmed by morphological examination, by DNA sequencing of the elongation factor 1-α gene, and by the use of species-specific primers for Fusarium oxysporum, F. proliferatum, and F. culmorum. Within F. oxysporum, isolates clustered in two clades suggesting different origins of F. oxysporum forms pathogenic to onion. These clades were present in each sampled region. Onion and six related Allium species were screened for resistance to Fusarium basal rot using one F. oxysporum isolate from each clade, and one F. proliferatum isolate. High levels of resistance to each isolate were found in Allium fistulosum and A. schoenoprasum accessions, whereas A. pskemense, A. roylei and A. galanthum showed intermediate levels of resistance. Among five A. cepa cultivars, ‘Rossa Savonese’ was also intermediately resistant. Regarding the current feasibility for introgression, A. fistulosum, A. roylei and A. galanthum were identified as potential sources for the transfer of resistance to Fusarium into onion.     

Cytological events in tomato leaves inoculated with conidia of <Emphasis Type="Italic">Blumeria graminis</Emphasis> f. sp. <Emphasis Type="Italic">hordei</Emphasis> and <Emphasis Type="Italic">Oidium neolycopersici</Emphasis> KTP-01

Leaves of tomato and barley were inoculated with conidia of Blumeria graminis f. sp. hordei race 1 (R1) or Oidium neolycopersici (KTP-01) to observe cytological responses in search of resistance to powdery mildew. Both conidia formed appressoria at similar rates on tomato or barley leaves, indicating that no resistance was expressed during the prepenetration stage of these fungi. On R1-inoculated tomato leaves, appressoria penetrated the papillae, but subsequent haustorium formation was inhibited by hypersensitive necrosis in the invaded epidermal cells. On the other hand, KTP-01 (pathogenic to tomato leaves) successfully developed functional haustoria in epidermal cells to elongate secondary hyphae, although the hyphal elongation from some conidia was later suppressed by delayed hypersensitive necrosis in some haustorium-harboring epidermal cells. Thus, the present study indicated that the resistance of tomato to powdery mildew fungi was associated with a hypersensitive response in invaded epidermal cells but not the prevention of fungal penetration through host papilla.     

A new<Emphasis Type="Italic">Aphidius</Emphasis> species (Hymenoptera: Braconidae: Aphidiinae) from high-montane areas of southeastern Europe

Aphidius montenegrinus sp.n. from Serbia and Montenegro is described and illustrated. It parasitizedAcyrthosiphon daphnidis Ilharco, onDaphne alpina L. The parasitoid was described and illustrated using scanning electron microscope photographs and line drawing. The new species is a member of theAcyrthosiphon aphid parasitoid guild and was collected from Zabojsko Jezero Lake in Montenegro. The parasitoid and the hyperparasitoid spectrum ofA. daphnidis are presented for the first time. http://www.phytoparasitica.org posting April 30, 2004.     

Cloning of the pathogenicity-related gene <Emphasis Type="Italic">FPD1</Emphasis> in <Emphasis Type="Italic">Fusarium oxysporum</Emphasis> f. sp. <Emphasis Type="Italic">lycopersici</Emphasis>

We selected a reduced-pathogenicity mutant of Fusarium oxysporum f. sp. lycopersici, a tomato wilt pathogen, from the transformants generated by restriction enzyme-mediated integration (REMI) transformation. The gene tagged with the plasmid in the mutant was predicted to encode a protein of 321 amino acids and was designated FPD1. Homology search showed its partial similarity to a chloride conductance regulatory protein of Xenopus, suggesting that FPD1 is a transmembrane protein. Although the function of FPD1 has not been identified, it does participate in the pathogenicity of F. oxysporum f. sp. lycopersici because FPD1-deficient mutants reproduced the reduced pathogenicity on tomato.The nucleotide sequence data reported are available in the DDBJ/EMBL/GenBank databases under the accession number AB110097     

Resistance to <Emphasis Type="Italic">Penicillium</Emphasis><Emphasis Type="Italic">hirsutum</Emphasis> Dierckx in garlic accessions

Among the factors affecting the quality and yield of garlic production, blue mold caused by -- Penicillium spp. -- is responsible for economical losses in many countries. Allicin, present in garlic bulbs, has been suggested as having antifungal activity against some Penicillium species. This study was conducted to evaluate the response of garlic accessions against Penicillium hirsutum infection and to compare this response with bulb allicin content. Twelve garlic accessions were inoculated with P. hirsutum, and assayed in greenhouse and growth chamber experiments. Plant growth parameters and the fungal production of conidia were evaluated. Significant differences were found among the accessions. Accessions Castaño and Morado were most resistant whereas AR-I-125 and Fuego were always severely affected by the disease. A low correlation was found (r = 0.17) between allicin content and tolerance, indicating that allicin is not the main factor involved in the resistance against P. hirsutum.     

Screening of cultivated and wild adzuki bean for resistance to race 3 of <Emphasis Type="Italic">Cadophora gregata</Emphasis> f. sp. <Emphasis Type="Italic">adzukicola</Emphasis>, cause of brown stem rot

Two diseases of adzuki bean, brown stem rot (BSR, caused by Cadophora gregata f. sp. adzukicola) and adzuki bean Fusarium wilt (AFW, caused by Fusarium oxysporum f. sp. adzukicola), are serious problems in Hokkaido and have been controlled using cultivars with multiple resistance. However, because a new race of BSR, designated race 3, was identified, sources of parental adzuki bean for resistance to race 3 were needed. Therefore, we examined 67 cultivars and lines of cultivated and wild adzuki bean maintained at the Tokachi Agricultural Experiment Station using a root-dip inoculation method. Consequently, nine adzuki bean cultivars, one wild adzuki bean accession and 30 lines (including two lines resistant to all the three races of BSR and AFW) were confirmed to be resistant or tolerant to race 3 of BSR, and we found a cultivar Akamame as well as a wild adzuki bean Acc2515 to be a new source for a resistance gene to the race 3. This cultivar also holds promise as a source of resistance against other races of BSR and AFW.     

Inhibition of germination of<Emphasis Type="Italic">Orobanche ramosa</Emphasis> seeds by<Emphasis Type="Italic">Fusarium</Emphasis> toxins

Eighteen toxins produced byFusarium species were tested at different concentrations onOrobanche ramosa seeds to evaluate their effectiveness in inhibiting germination. Many of the toxins were active at the highest concentration used. Seven of them,viz. fusarenon X, nivalenol, deoxynivalenol, T-2 toxin, HT-2 toxin, diacetoxyscirpenol and neosolaniol, were highly active at 10μM, causing 100% inhibition of germination. Many of them were still active when assayed at a concentration ten times lower, with T-2, HT-2, nivalenol, neosolaniol and diacetoxyscirpenol still able to cause total inhibition; the last mentioned was very active also at 0.1μM, causing more than 90% inhibition. The results show that the use of toxic secondary metabolites could represent a useful alternative strategy in the management of parasitic weeds, by interfering with the induced germination process, and that fungal culture extracts could be an interesting source of new compounds acting as natural and original herbicides. http://www.phytoparasitica.org posting Sept. 18, 2002.     

Specific inhibition of spore germination of <Emphasis Type="Italic">Alternaria brassicicola</Emphasis> by fistupyrone from <Emphasis Type="Italic">Streptomyces</Emphasis> sp. TP-A0569

Fistupyrone (FP), a metabolite from Streptomyces sp. TP-A0569, inhibited the in vivo infection of Chinese cabbage seedlings by Alternaria brassicicola. To detect the possible action sites of FP, the effect of FP on the infection behavior of A. brassicicola and A. alternata was investigated. When spores of A. brassicicola were suspended in FP solution and inoculated on host leaves, FP at 0.1ppm significantly inhibited spore germination, appressorial formation, and infection hypha formation of A. brassicicola. Host-specific AB-toxin production and lesion formation by A. brassicicola spores were also reduced significantly by treatment with FP 1ppm. The effect of FP seemed to be irreversible because significant washing of FP-treated spores with distilled water (DW) did not change the inhibitory effects. In contrast, A. alternata isolates such as Japanese pear pathotype, apple pathotype, and saprophyte behaved almost equally in both FP- and DW-treated spores. Mycelial dry weight in potato dextrose broth and mycelial diameters on potato dextrose agar, gelatin glucose agar, and Czapek solution agar of both A. brassicicola and A. alternata were not different with or without addition of FP. These results indicate that FP at low concentrations has a fungicidal effect on spores of A. brassicicola but not on spores of A. alternata; FP also does not affect the vegetative phase of these fungi.     

Fusarium rot of hyacinth caused by <Emphasis Type="Italic">Gibberella zeae</Emphasis> (anamorph: <Emphasis Type="Italic">Fusarium</Emphasis><Emphasis Type="Italic"> graminearum</Emphasis>)

Severe rot of leaves, peduncles and flowers caused by Gibberella zeae (anamorph: Fusarium graminearum) was found on potted plants of hyacinth (Hyacinthus orientalis), a liliaceous ornamental, in greenhouses in Kagawa Prefecture, Japan, in January 2001. This disease was named “Fusarium rot of hyacinth” as a new disease because only the anamorph, F. graminearum, was identified on the diseased host plant. The authors contributed equally to this work. The fungal isolate and its nucleotide sequence data obtained in this study were deposited in the Genebank, National Institute of Agrobiological Sciences and the DDBJ/EMBL/GenBank databases under the accession numbers MAFF239499 and AB366161, respectively.     

Insecticidal activity of crude seed extracts of<Emphasis Type="Italic">Annona</Emphasis> spp.,<Emphasis Type="Italic">Lansium domesticum</Emphasis> and<Emphasis Type="Italic">Sandoricum koetjape</Emphasis> against lepidopteran larvae

Crude ethanolic seed extracts ofAnnona muricata, A. squamosa (Annonaceae),Lansium domesticum andSandoricum koetjape (Meliaceae) collected from different locations and years in Maluku, Indonesia, were screened for inhibition of larval growth against the polyphagous lepidopteranSpodoptera litura (Noctuidae). Extracts ofA. squamosa were significantly more active (20-fold) than those ofA. muricata. A. squamosa collected from Namlea yielded the extracts with the greatest inhibitory activity. There were significant differences among locations for bothA. squamosa andA. muricata but not forL. domesticum andS. koetjape. Extracts ofA. squamosa, collected from Namlea, inhibited larval growth in a dose-dependent manner, with a dietary EC₅₀ (effective concentration to inhibit growth by 50% relative to controls) of 191.7 ppm fresh weight. Extracts ofA. squamosa collected from individual trees in Namlea also varied in growth inhibitory effect againstS. litura andTrichoplusia ni larvae. This species is a candidate for development of a botanical insecticide for local use in Indonesia. http://www.phytoparasitica.org posting Dec. 1, 2003.     

Characterization of <Emphasis Type="Italic">Pectobacterium carotovorum</Emphasis> subsp. <Emphasis Type="Italic">carotovorum</Emphasis> causing soft-rot disease on <Emphasis Type="Italic">Pinellia ternata</Emphasis> in China

Pinellia ternata is a traditional Chinese herb which has been used in China for over 1,000 years. A soft-rot disease characterized by water-soaked lesions and soft-rot symptoms with a stinking odour was commonly observed in cultivated fields of this plant, and Pectobacterium-like bacteria were consistently isolated from the infected tissues. Two typical strains (SXR1 and ZJR1), isolated from Shanxi and Zhejiang, respectively, were identified. Pathogenicity tests revealed that these strains were virulent to P. ternata and induced the same symptoms as observed in the field. Characterization involving fatty acid profile, metabolic and physiological properties, 16S rDNA sequence and PCR-RFLP identified both isolates as P. carotovorum subsp. carotovorum (Pcc). The 16S rDNA of both isolates shared 97–99% sequence similarity with that of Pcc strains. The phylogenetic trees showed that both isolates were clustered in the group of Pcc and P. carotovorum subsp. odorifera and both PCR-RFLP profiles were consistent with the pattern E produced by the minority of Pcc strains. Thus, isolates SXR1 and ZJR1 were characterized as Pcc in spite of some differences. This is the first report that Pcc has been proven as a causal agent of soft-rot disease on P. ternata.     

Natural enemies of the pear psylla<Emphasis Type="Italic">Cacopsylla pyri</Emphasis> in treated<Emphasis Type="Italic">vs</Emphasis> untreated pear orchards in Antalya,Turkey

Populations of pear psylla,Cacopsylla pyri (L.) (Rhynchota: Psyllidae), and its natural enemies were sampled on pears in Antalya province during the years 2000–2002. Thirty-two species of predators and three species of parasitoids were detected to be associated withC. pyri in Antalya province. The heteropterans (especially anthocorid species) were the most abundant predator group. Among the anthocorids,Anthocoris nemoralis (Fabricius) (Heteroptera: Anthocoridae), whose population was closely related to the dynamics of the pear psylla population, was generally the principal antagonist ofC. pyri. Other species recorded during the study were the miridDeraeocoris spp., the chrysopidChrysoperla carnea L., and many coccinellid species. Although these predators are polyphagous, as are theOrius species, their populations were related to the psylla fluctuations. Among the parasitoid complex belonging to the order Hymenoptera, the encyrtidTrechnites psyllae (Ruschka) was the only primary parasitoid. Two hyperparasites,viz., Syrphophagus mamitus (Walker) andPachyneuron aphidis (Bouché) (Encyrtidae and Pteromalidae, respectively), were detected in the surveys. Also, this study revealed new information concerning the pear psylla parasitoid complex in Turkey. WhileT. psyllae andS. mamitus are new records to Turkish parasitoid fauna,C. pyri is a new host record forP. aphidis. The population development and abundance of pear psylla and its natural enemies, as well as the parasitization rates in treated and untreated pear orchards, are presented here. http://www.phytoparasitica.org posting May 6, 2004.     

Note: Tachinid parasitoids of<Emphasis Type="Italic">Ancyrosoma leucogrammes</Emphasis> and notes on parasitization rates of<Emphasis Type="Italic">Clytiomya dupuisi</Emphasis>

The study deals with the tachinid parasitoids ofAncyrosoma leucogrammes (Gmelin) (Heteroptera: Pentatomidae):Clytiomya dupuisi Kugler,Clytiomya sola (Rondani) andGymnosoma clavatum (Rohdendorf) (Diptera: Tachinidae). All species are recorded for the first time as parasitoids ofA. leucogrammes, andC. dupuisi was reared for the first time from a host. The parasitization rates ofC. dupuisi on adults ofA. leucogrammes varied from 7% to 9% between 1994 and 1999.C. sola andG. clavatum were reared in only small numbers. http://www.phytoparasitica.org posting July 10, 2003.     

Structural conservation of the <Emphasis Type="Italic">hrp</Emphasis> gene cluster in <Emphasis Type="Italic">Xanthomons oryzae</Emphasis> pv. <Emphasis Type="Italic">oryzae</Emphasis>

The clustered hrp genes encoding the type III secretion system in the Japanese strains MAFF301237 and MAFF311018 of Xanthomonas oryzae pv. oryzae were sequenced and compared. The strains differ in their pathogenicity, location, and year of isolation. A 30-kbp sequence comprising 29 open reading frames (ORFs) was identical in its structural arrangement in both strains but differed from X. campestris pv. campestris, X. axonopodis pv. citri, and X. axonopodis pv. glycines in certain genes located between the hpaB-hrpF interspace region. The DNA sequence and the putative amino acid sequence in each ORF was also identical in both X. oryzae pv. oryzae strains as were the PIP boxes and the relative sequences. These facts clearly showed that the structure of the hrp gene cluster in X. oryzae pv. oryzae is unique.     

Tachinidae parasitoids of<Emphasis Type="Italic">Traumatocampa ispartaensis</Emphasis> from Turkey

Tachinid parasitoids ofTraumatocampa ispartaensis Doğanlar & Avcı (Lepidoptera, Thaumetopoeidae), which was found to be a new species, were collected from the cedar forests around Isparta-Kapıdağ. The species found wereBlondelia nigripes (Fall.),Compsilura concinnata (Meig.),Pales processioneae (Ratz.),Phryxe caudata (Rond.),Exorista segregata (Rond.) andCarcelia iliaca (Ratz.). Within the six species of Tachinidae,B. nigripes was the most common one, parasitizing up to 4.6% ofT. ispartaensis pupae. http://www.phytoparasitica.org     

Anthracnose of <Emphasis Type="Italic">Polygonatum falcatum</Emphasis> caused by <Emphasis Type="Italic">Colletotrichum dematium</Emphasis>

Severe spotting, blight and drop of leaves caused by Colletotrichum dematium were found on potted plants of Polygonatum falcatum, a liliaceous ornamental, in open fields in Kagawa Prefecture, Japan, in May 2001. This new disease was named anthracnose of P. falcatum. Keisuke Tomioka, Jouji Moriwaki, Toyozo Sato contributed equally to this work. The fungal isolate and its nucleotide sequence data obtained in this study were deposited in Genebank, National Institute of Agrobiological Sciences and the DDBJ/EMBL/GenBank databases under accessions MAFF239500 and AB334523, respectively.