Pathogenicity of Metarhizium anisopliae (Deuteromycetes) and permethrin to Ixodes scapularis (Acari: Ixodidae) nymphs

• Published in: Experimental & applied acarology Vol. 35; no. 4; pp. 301 - 316
• Main Authors: Hornbostel, V.L, Zhioua, E, Benjamin, M.A, Ginsberg, H.S, Ostfeld, R.S
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer 01.01.2005; Springer Nature B.V; Springer Verlag
• Subjects: Acari; Acaricides; Animals; Bioassays; Biological and medical sciences; biological control agents; Deuteromycetes; entomopathogenic fungi; Fundamental and applied biological sciences. Psychology; Insecticides; Ixodes; Ixodes - microbiology; Ixodes scapularis; Ixodidae; lethal dose 50; Life Sciences; Medically important nuisances and vectors, pests of stored products and materials: population survey and control; Metarhizium anisopliae; Microbiology and Parasitology; Mitosporic Fungi; Mitosporic Fungi - physiology; Mortality; Mycology; Nymph; Nymph - microbiology; nymphs; pathogenicity; Pathogens; Permethrin; Pest Control, Biological; pyrethroid acaricides; Pyrethroids; Synergism; tick control; Time Factors; Vectors. Intermediate hosts; New York; Lyme disease; Insecticide; Permethrin; Biological control; Pyrethroids; Ixodes scapularis; Tick control; Fungi; Acaricide; Acari; Spirochaetosis; Metarhizium anisopliae; Chemical control; Fungi Imperfecti; Acarogenous; Vector; Ixodidae; Thallophyta; Parasitiformes; Borrelia infection; Pesticides; Parasite; Infection; Mycoparasite; Pathogenicity; Arachnida; Ixodida; Arthropoda; Bacteriosis; Ectoparasite; Invertebrata; tick control; biological control; lyme disease
• ISSN: 0168-8162; 1572-9702
• DOI: 10.1007/s10493-004-5437-z

Effectiveness of the entomopathogenic fungus Metarhizium anisopliae, for controlling nymphal Ixodes scapularis, was tested in laboratory and field trials. In the laboratory, M. anisopliae (Metschnikoff) Sorokin strain ESC1 was moderately pathogenic, with an LC50 of 10(7) spores/ml and induced 70% mortality at 10(9) spores/ml. In a field study, however, 10(9) spores/ml M. anisopliae did not effectively control questing I. scapularis nymphs, and significant differences were not detected in pre- and post-treatment densities. For nymphs collected and returned to the laboratory for observation, mortality was low in treatment groups, ranging from 20 to 36%. To assess whether a chemical acaricide would synergistically enhance pathogenicity of the fungus, we challenged unfed nymphal I. scapularis with combinations of M. anisopliae and permethrin, a relatively safe pyrethroid acaricide, in two separate bioassays. Significant interactions between M. anisopliae and permethrin were not observed, supporting neither synergism nor antagonism.