Muscardine Fungus Research Articles

Inhibition of protease from muscardine fungus by the inhibitor in the silkworm haemolymph and tissues

Inhibition of protease from muscardine fungus by the inhibitor in the silkworm haemolymph and tissues

ABSENCE OF FATTY ACID GERMINATION INHIBITORS FOR CONIDIA OF BEAUVERIA BASSIANA ON THE INTEGUMENT OF THE BARK BEETLE DENDROCTONUS PONDEROSAE (COLEOPTERA: SCOLYTIDAE)

Ether extracts from Eurygaster integriceps (Evlakhova and Chekhourina 1962) and Bombyx mori (Koidsumi 1957) have been found to inhibit germination of conidia of the white muscardine fungus, Beauveria bassiana, and of Aspergillus flavus, respectively. Free fatty acids, such as caprylic acid, which inhibit the germination of B. bassiana conidia (Smith and Grula 1981), have been found on the cuticle of several insects (Smith and Grula 1982; Saito and Aoki 1983). However, Smith and Grula (1982) found that the toxicity of free fatty acids to B. bassiana conidia in vitro is dependent on the nutritional conditions present. The germination of B. bassiana conidia onthe integument of the mountain pine beetle, Dendroctonus ponderosae, is seldom observed without nutrient enhancement (Hunt et al. 1984). My objective was to determine whether the relative absence of conidial germination on D. ponderosae cuticle is due in part to the action of toxic free fatty acids.

Nutrient-mediated germination of Beauveria bassiana conidia on the integument of the bark beetle Dendroctonus ponderosae (Coleoptera:Scolytidae)

Field-collected adult mountain pine beetles, Dendroctonus ponderosae, were inoculated with the white muscardine fungus, Beauveria bassiana, and thoroughly examined externally with a scanning electron microscope. Germinating conidia were found at a very low incidence, and only on antennal clubs. However, mortality of inoculated controls was high, and B. bassiana was confirmed as the causative agent. Germination on the cuticle was greatly increased by sonication of adult beetles. The hypothesis that hemolymph released through sonication-damaged membranes provided a nutrient stimulus that enhanced conidial germination was tested by placing hemolymph or yeast-malt extract broth on the cuticle of otherwise nontreated beetles, which were then inoculated with conidia. Significant germination occurred on the cuticle of these beetles. Therefore, a limiting factor for conidial germination on the sclerotized cuticle of D. ponderosae is probably a lack of sufficient nutrients.

Fungicides to Control Green Muscardine Fungus, a Disease of Zigzag Leafhopper in Rearing Cages

Fungicides to Control Green Muscardine Fungus, a Disease of Zigzag Leafhopper in Rearing Cages

Metarhizium anisopliae . [Descriptions of Fungi and Bacteria

Abstract A description is provided for Metarhizium anisopliae . Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Wide range of insects, including Orthoptera, Coleoptera, Lepidoptera, Hemiptera and Hymenoptera , also Arachnida , from soil and from a crocodile (Austwick in Tulloch, 1976). Latch (1965) quotes 166 insect species attacked in nature, and Veen (1968) lists 204 hosts under their respective orders from the literature up to 1965. GEOGRAPHICAL DISTRIBUTION: World wide. DISEASE: The green muscardine fungus. Entry is probably both by ingestion of spores and by penetration through the integument. For an account of the work of Zacharuk (1970-1974) on the germination of spores, formation of appressorial cells, penetrant pegs through the epicuticle and sub-epicuticular penetrant plates giving rise to hyphal bodies that circulate in thehaemolymph, see Ferron (1978). All stages of the host are affected, chlamydospores forming in the cadaver and subsequently germinating to produce the familiar green spores on the surface. On a given host, strains vary in their virulence (Ferron, 1978). The fungus causes an economically important disease of silkworms, and Veen (1968) gives an account of the disease in the locust.

Metarrhizium anisopliae(metschnikoff) sorokin strains in New Zealand and their possible use for controlling pasture-inhabiting insects

Abstract The green muscardine fungus, Metarrhizium anisopliae (Metsch.) Sorokin, is recorded for the first time on Costelytra zealandica White, Heteronychus sanctae-helenae Blanch., and Pericoptus truncatus Fabr. The three distinctive culture types isolated from these hosts and from Oxycanus sp. are described, and their selective pathogenicity is discussed and compared with cultures of M. anisopliae and Metarrhizium brunneum obtained from the Commonwealth Mycological Institute, Kew, and the Agricultural Research Service Collection, Peoria, Illinois. It is considered that this culture of M. brunneum comes within the species limits of M. anisopliae. Literature on M. anisopliae, its host range, and the use of the fungus for biological control, is reviewed. From a consideration of the strains of M. anisopliae in this country and an evaluation of overseas work, it is believed that this fungus is unlikely to be of much use for biological control of injurious pasture-inhabiting grubs in New Zealand.

Beauveria Bassiana as a Pathogen of Scolytus Multistriatus

This muscardine fungus was the organism most frequently encountered in a survey for pathogens of the smaller European elm bark beetle, Scolytus multistriatus Marsh., and was found in larvae from five widely separated areas in Connecticut. Up to 6.5% of overwintering larvae in trees cut from city streets were infected, but under certain environmental conditions the fungus may be much more effective in killing the beetles. In one epizootic caused by this fungus, 97% of larvae were killed in the bark of trees in a shady grove, less than 4% in nearby trees standing in the open. In controlled laboratory experiments the fungus killed up to 99% of the larvae in 5 days. Pupae and adults were also susceptible, though adults were slightly less so than larvae.