Occurrence of Verticicladiella wagenerii and Its Perfect State, Ceratocystis wageneri sp. nov., in Insect Galleries

Goheen, Donald J.; Cobb, F. W.

doi:10.1094/phyto-68-1192

Cited by 43 publications

(18 citation statements)

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“…The results of our study show clearly that G. wageneri is a heterothallic fungus and thus has the capacity to undergo sexual outcrossing. This provides strong evidence to suggest that Goheen and Cobb (1978) correctly identified the ascomata of this fungus in nature. Thus, it serves as an interesting example of a Leptographium sp.…”

Section: Discussionsupporting

confidence: 52%

“…The results of this study explain why these fungi failed to produce sexual states in the study by Duong et al (2012). Goheen and Cobb (1978) reported the discovery of a sexual state in the important conifer root pathogen G. wageneri, which was found in the galleries of Hylastes macer. This form of the fungus has never again been seen and there has been doubt as to whether these authors had possibly collected a sexual state of some other ophiostomatoid fungus (Harrington and Cobb, 1988).…”

Section: Discussionmentioning

confidence: 62%

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Mating type markers reveal high levels of heterothallism in Leptographium sensu lato

et al. 2016

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Species of Leptographium sensu lato (Ophiostomatales, Ascomycetes) are sap-stain fungi vectored by bark beetles (Coleoptera, Scolytinae) and some species cause or are associated with tree diseases. Sexual states have been reported for more than 30 species in this group and these have been treated in the sexual genus Grosmannia. No sexual state is known for at least 59 additional species and these reside in the genus Leptographium. The discovery of sexual states for species of Leptographium relies mainly on the presence of fruiting bodies on host tissue at the time of isolation and/or intensive laboratory mating studies, which commonly have a low levels of success. In this study, markers were developed to diagnose mating-type and to study sexual compatibility of species in Leptographium sensu lato using these markers. To achieve this objective, available mating type sequences for species of Leptographium sensu lato and Ophiostoma were obtained, aligned and used to design primers to amplify MAT genes in Grosmannia and Leptographium species. Using these primers, it was possible to amplify portions of the mating type genes for 42 species and to determine thallism, in many species for the first time. Surprisingly, the results showed that heterothallic and putatively heterothallic species are abundant (39 out of 42 species) in Leptographium sensu lato, and only three species were confirmed to be homothallic. The mating-type markers developed in this study will be useful for future studies concerning mating type and sexual compatibility of species in this genus.

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Section: Discussionsupporting

confidence: 52%

Section: Discussionmentioning

confidence: 62%

Mating type markers reveal high levels of heterothallism in Leptographium sensu lato

et al. 2016

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“…In the case of L. wageneri var. ponderosum, a sexual stage (= O. wageneri) was detected only once from ponderosa pines (Goheen and Cobb 1978). Sexual recombination may be a rare event in this pathogen (Otrosina and Cobb 1987), and we assume that the inoculum carried by the bark beetle consists predominantly of asexual conidia.…”

Section: Species Detected By Methods Described and Potential For Crossmentioning

confidence: 97%

“…Harr. (Harrington 1987), has been isolated only once from ponderosa pine (Goheen and Cobb 1978), and its ecological role remains unknown. No sexual stages of the varieties pseudotsugae and wageneri have been reported.…”

Section: Introductionmentioning

confidence: 99%

Detection and quantification of Leptographium wageneri, the cause of black-stain root disease, from bark beetles (Coleoptera: Scolytidae) in Northern California using regular and real-time PCR

Schweigkofler¹,

Otrosina²,

Smith³

et al. 2005

Can. J. For. Res.

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Black-stain root disease is a threat to conifer forests in western North America. The disease is caused by the ophiostomatoid fungus Leptographium wageneri (W.B. Kendr.) M.J. Wingf., which is associated with a number of bark beetle (Coleoptera: Scolytidae) and weevil species (Coleoptera: Curculionidae). We developed a polymerase chain reaction test to identify and quantify fungal DNA directly from insects. Leptographium wageneri DNA was detected on 142 of 384 bark beetle samples (37%) collected in Lassen National Forest, in northeastern California, during the years 2001 and 2002. Hylastes macer (LeConte) was the bark beetle species from which Leptographium DNA was amplified most regularly (2001: 63.4%, 2002: 75.0% of samples). Lower insect-fungus association rates were found for Hylurgops porosus (LeConte), Hylurgops subcostulatus (Mannerheim), Hylastes gracilis (LeConte), Hylastes longicollis (Swaine), Dendroctonus valens (LeConte), and Ips pini (Say). The spore load per beetle ranged from 0 to over 1 × 10 5 spores, with only a few beetles carrying more than 1 × 10 3 spores. The technique permits the processing of a large number of samples synchronously, as required for epidemiological studies, to study infection rates in bark beetle populations and to identify potential insect vectors. Résumé: Le noircissement des racines est une maladie qui menace les forêts de l'ouest de l'Amérique du Nord. La maladie est causée par Leptographium wageneri (W.B. Kendr.) M.J. Wingf., un champignon de la famille des Ophiostomataceae qui est associé à plusieurs espèces de scolytes (Coléoptères : Scolytidae) et de charançons (Coléoptères : Curculionidae). Nous avons mis au point un test de réaction en chaîne de la polymérase pour identifier et quantifier l'ADN fongique directement à partir des insectes. L'ADN de L. wageneri a été détecté sur 142 des 384 (37 %) échan-tillons de scolytes collectés dans la forêt nationale de Lassen, dans le nord-est de la Californie, au cours des années 2001 et 2002. Hylastes macer (LeConte) était l'espèce de scolyte à partir duquel l'ADN de Leptographium a été le plus régulièrement amplifié (2001 : 63,4 %, 2002 : 75,0 % des échantillons). Des taux d'association plus faibles ont été observés pour Hylurgops porosus (LeConte), Hylurgops subcostulatus (Mannerheim), Hylastes gracilis (LeConte), Hylastes longicollis (Swaine), Dendroctonus valens (LeConte) et Ips pini (Say). La charge de spores par insecte variait de 0 à plus de 1 × 10 5 spores, avec seulement quelques insectes transportant plus de 1 × 10 3 spores. La technique permet de traiter simultanément un grand nombre d'échantillons, comme l'exigent les études épidémiologiques pour étudier le taux d'infection dans les populations de scolytes et identifier les insectes vecteurs potentiels. [Traduit par la Rédaction] Schweigkofler et al. 1808

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“…and L. procerum, that cause disease and mortality in older saplings and trees (Goheen and Cobb 1978;Harrington et al 1985;Witcosky et al 1986a,b;Hansen and Goheen 1988;Klepzig et al 1991Klepzig et al , 1995Goheen and Hansen 1993;Harrington, 1993;Schweigkofler et al 2005). Beetles reproducing in stressed or diseased trees transmit root disease pathogens to susceptible root systems, from which the pathogen can spread to adjacent healthy root systems over short distances (Harrington 1993).…”

Section: Ecologymentioning

confidence: 99%

Biology and Management of Root-Feeding Beetles (Coleoptera: Curculionidae) in North American Conifer Forests and Plantations

Schowalter

2018

Journal of Integrated Pest Management

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Root-feeding beetles, including several species of Hylastes Erichson (Coleoptera: Curculionidae), Hylurgops LeConte (Coleoptera: Curculionidae), Hylobius Gemar (Coleoptera: Curculionidae), Pachylobius LeConte (Coleoptera: Curculionidae), Pissodes Germar (Coleoptera: Curculionidae), and Steremnius Schönherr (Coleoptera: Curculionidae), have emerged as serious problems in conifer plantations and forests in the United States and Canada in recent decades. Root-feeding beetles are particularly associated with stressed, diseased, or injured trees. Emerging adults kill seedlings by girdling them at the root collar and kill older trees, at least in the North and West, by transmitting fungal root pathogens in the genus Leptographium Lagerberg & Melin (Ophiostomatales: Ophiostomataceae). In the South seedling, mortality can be as high as 60% for seedlings planted in winter following fall harvest. For stands harvested after 1 July, planting should be delayed a full year. Broadcast insecticides can be used, but dipping seedlings in 0.75% permethrin prior to planting and physical barriers to feeding have proven effective. However, an integrated pest management approach that emphasizes a combination of measures to minimize attraction of beetles and to maintain health of host trees is recommended. Shelterwood harvest and soil scarification can create site conditions that minimize attraction of root beetles. Precommercial thinning and prescribed fire are often used to reduce tree competition and reduce vulnerability to stem-colonizing bark beetles. However, root beetles are attracted to thinned or burned stands, for at least 6-7 mo. Therefore, thinning should be avoided in areas of high risk for root disease transmission or, when necessary, thinning should be implemented during June or July following beetle dispersal in May. Semiochemicals can be used to monitor abundances of root beetles.

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Occurrence of Verticicladiella wagenerii and Its Perfect State, Ceratocystis wageneri sp. nov., in Insect Galleries

Cited by 43 publications

References 0 publications

Mating type markers reveal high levels of heterothallism in Leptographium sensu lato

Mating type markers reveal high levels of heterothallism in Leptographium sensu lato

Detection and quantification of Leptographium wageneri, the cause of black-stain root disease, from bark beetles (Coleoptera: Scolytidae) in Northern California using regular and real-time PCR

Biology and Management of Root-Feeding Beetles (Coleoptera: Curculionidae) in North American Conifer Forests and Plantations

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