MSA - Ecology/Pathology
Tuininga, Amy , Morath, Shannon , Greengarten, Pamela , Daniels, Thomas , Norelus, Herby , Falco, Richard .
Timing of tick pathogen presence in the environment.
Ixodes scapularis, the blacklegged tick, is the vector of Borrelia burgdorferi, the etiologic agent of Lyme disease. Biocontrol strategies using entomopathogenic fungi have been suggested to control tick populations and the spread of Lyme disease. Because the virulence of entomopathogenic fungi varies with changes in relative humidity and temperature in the lab, seasonal weather changes may also affect fungal pathogenicity in situ. Therefore, we hypothesized that fungi which are most virulent under optimal laboratory conditions may function differently under the natural variability of weather conditions in the field. The objective of this study was to examine seasonal patterns of frequency of potential entomopathogens and to determine whether these locally isolated species were virulent to ticks in the laboratory and field. To do this, soil and host-seeking ticks were collected from forested plots periodically from June 2007 through December 2008 in Westchester County, NY, and plated on ½-strength potato dextrose agar (PDA). Fungi were sub-cultured until pure isolates were obtained. Fungal DNA was extracted and amplified with PCR using primers ITS-1F and ITS-4, and sequenced. We then tested locally isolated fungi for virulence to nymphal I. scapularis. We identified a minimum of 73 species of fungi: 55 isolated from soils and 24 from ticks. Of the 35 fungal isolates tested for virulence, the12 taxa determined to be pathogenic were Fusarium lateritium, Hypocrea lixii, Mortierella gamsii, Mortierella sp., Mucor hiemalis, Mucor sp., Paecilomyces lilacinus, Penicillium brevicompactum, Penicillium sclerotiorum, Penicillium soppii, Penicillium sp., and Pestalotiopsis sp. Hypocrea lixii and Penicillium soppii were also significantly virulent in the field, decreasing tick survival by 39% and 26%, respectively, compared to control plots. These data suggest that there may be numerous entomopathogenic fungi in nature whose virulence varies seasonally and which may play a significant role in regulating various stages of I. scapularis.
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1 - Fordham University, Louis Calder Center - Biological Research Station and Department of Biology, P.O. Box 887, 53 Whippoorwill Road, Armonk, NY, 10504, USA
2 - Fordham University and New York State Department of Health, Arthropod-Borne Disease Program, Louis Calder Center, P.O. Box 887, 53 Whippoorwill Road, Armonk, NY , 10504, USA
Presentation Type: Poster:Posters for Topics
Location: Event Tent/Cliff Lodge
Date: Tuesday, July 28th, 2009
Time: 5:30 PM