Untersuchungen zur Physiologie insektent�tender Pilze

Huber, Johann

doi:10.1007/bf00412319

Cited by 57 publications

(8 citation statements)

References 9 publications

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“…Adults of Hylobius are known to be long-lived (DAVIS and LUND 1966), spending much of their life in or on soil and forest litter, where microbiota are prolific. Antibiosis exerted by some of these organisms against entomopathogenic fungi has been verified repeatedly (DONAUBAUER 1959;HUBER 1958;WARTENBERG and FREUND 1961;WALSTAD et al 1970). In the present study, fungal and bacterial contaminants were constantly present on the cuticle of beetles.…”

Section: Discussionmentioning

confidence: 92%

Green muscardine disease of Hylobius pales (Herbst) (Coleoptera: Curculionidae)

Schabel

1976

Zeitschrift für Angewandte Entomologie

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The mode of infection of larval and adult Hylobius pales with Metarrhizium anisopliae, an entomopathogenic fungus, was investigated by means of histology, scanning electron microscopy and the controlled application of conidia. The objective of the study was to explain the large amounts of inoculum necessary to achieve high beetle mortality under field conditions. Spore germination was minimal on beetles and intermediate on larvae, apparently as a result of antibiosis from bacterial and fungal contaminants. High germination percentages resulted after the antibiotic principle was eliminated by surface-sterilizing insect parts. Germ tubes grew extensively over the host surface before they produced appressoria. Penetration of the integument was observed to only take place through procuticular portions, never through sclerites. While no proof for intestinal infection was obtained, invasion from within the buccal cavity was confirmed.Despite limitations imposed by antibiosis, the growth of germ tubes over the host surface and the impenetrability of sclerites, the following field trials with Metarrhizium against Hylobius are encouraged. Plants to be protected should be dipped in spore suspensions at the time of planting. Spores could be applied around the base of plants to be protected. Any means of infecting larvae would seem superior to efforts aimed at infecting the beetles.Present address: College of Natural Resources,

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Section: Discussionmentioning

confidence: 92%

Green muscardine disease of Hylobius pales (Herbst) (Coleoptera: Curculionidae)

Schabel

1976

Zeitschrift für Angewandte Entomologie

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“…Therefore, we hypothesize that B. bassiana conidia may survive in a conidial state and maintain their ability to grow on Martin's medium, but lose their tolerance against D0C2 medium around 12 months. Huber (1958) stated B. bassiana conidia did not germinate when mixed in fresh soil, although they germinated in sterilized soil. Our observations revealed the same phenomenon.…”

Section: Discussionmentioning

confidence: 99%

Density dynamics of the entomopathogenic fungus, Beauveria bassiana Vuillemin (Deuteromycotina: Hyphomycetes) introduced into forest soil, and its influence on other soil microorganisms.

Shimazu

Maehara

Sato

2002

Appl. Entomol. Zool.

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Beauveria bassiana conidia were mixed into the forest soil, and the density dynamics of soil microorganisms were investigated using selective media to clarify the impact of B. bassiana application on them. The density of bacteria was between 1ϫ10 6 and 10 8 CFU/g, and that of actinomycetes was around 1ϫ10 6 to 10 7 CFU/g regardless of the addition of B. bassiana. Densities of general fungi and of B. bassiana in the non-treatment plot were always approximately 1ϫ10 5 CFU/g and 1ϫ10 2 CFU/g, respectively. On the other hand, densities of both general fungi and B. bassiana in the treatment plot increased to 3 to 5ϫ10 7 CFU/g immediately after the mixing of B. bassiana. Densities gradually decreased to 1/10 the density after 12 months. Microscopic observations revealed that B. bassiana conidia do not germinate in non-sterilized soil, but they do germinate in sterilized soil. Densities of fungi other than B. bassiana could not be measured in the treatment plot. However, they were not thought to be affected by mixing of B. bassiana, because the metabolism of B. bassiana seemed to be very inert.

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“…Several investigators have established that B. hassiana. produces many types of exocellular enzymes, including chitinases, proteases, and lipases (Hiiber, 1958;Leopold and Samsinakova, 1970;Grula et al, 1978;Pekrul and Grula, 1979) . investigated the interaction between B. bassiana and H. zea and concluded that the young, germinating hyphae of B. bassiana must produce sequentially a proteinase and a chitinase to dissolve the insect cuticular envelope.…”

Section: Penetrationmentioning

confidence: 99%

The colonization of corn, Zea mays L., by the entomopathogenic fungus, Beauveria bassiana (Balsamo) Vuillemin

Wagner

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The ubiquitous entomopathogenic fungus Beauveria hassiana (Balsamo) Vuillemin (Deuteromycotina: Hyphomycetes) has been extensively investigated to suppress populations of several insect species worldwide including the European corn borer Ostrinia nubilalis (Hiibner) (Lepidoptera: Pyralidae) for over 60 years. In several studies investigating the response of inbred corn lines to plant pathogenic fungi, B. bassiana was isolated from the pith of plants. Subsequent field studies have shown that B. bassiana placed in or on corn plants in the vegetative stage persisted for greater than 90 days and remained virulent to O. nubilalis throughout the growing season. Even though these field studies demonstrated the potential use of this relationship, the manner in which B. bassiana colonizes Zea mays L. was not known. The following study was initiated to elucidate the methods of adhesion, penetration and colonization by B. bassiana on the corn leaf surface. Light and electron microscopic techniques were utilized to investigate the interactions between these two organisms. Understanding this unique relationship will be invaluable in further development and utilization of this fungus to manage insect pests of food plants. vi The adhesion and subsequent growth and penetration on corn leaves by B. bassiana. is very similar to the germination and penetration by B. bassiana on insect cuticles. After inoculation using a foliar spray of S. bassiana conidia, germinating hyphae grow randomly across the leaf surface. Often a germ tube fomed from a conidium and elongated only a short distance before terminating its growth. All developing hyphae on the leaf surface do not penetrate the cuticular surface. However, when penetration does occur, the penetration site{s) are randomly located across the surface. Apparently B. bassiana does not require specific topographic signals at an appropriate entry site as do some phytopathogenic fungi. Long hyphal structures were observed to follow the leaf apoplast in any direction from the point of penetration. In some cases, the hyphae were observed within xylem elements. Because vascular bundles are interconnected throughout the corn plant, this may explain the way the fungus travels within the plant and ultimately provides overall insecticidal protection. Virulence of B. bassiana after colonizing the corn plant was tested and it was determined that this fungus did not lose any virulence toward the European corn borer. This is the first report illustrating the mode of penetration by B. bassiana into Z. mays. This special endophytic relationship between an entomopathogenic fungus and vii a plant suggests possibilities for biological control, including utilization of indigenous fungal inocula as insecticides. 1 CHAPTER 1: 6 developing research on entomogenous fungi (Ferron, 1578). Reviews on the identification and use of entomopathogenic fungi as biocontrol agents were edited by Burges and Hussey (1971) and Burges (1981). Worldwide, a few genera of fungi such as Beauveria and Metarhizium, have been used...

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Untersuchungen zur Physiologie insektent�tender Pilze

Cited by 57 publications

References 9 publications

Green muscardine disease of Hylobius pales (Herbst) (Coleoptera: Curculionidae)

Green muscardine disease of Hylobius pales (Herbst) (Coleoptera: Curculionidae)

Density dynamics of the entomopathogenic fungus, Beauveria bassiana Vuillemin (Deuteromycotina: Hyphomycetes) introduced into forest soil, and its influence on other soil microorganisms.

The colonization of corn, Zea mays L., by the entomopathogenic fungus, Beauveria bassiana (Balsamo) Vuillemin

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