Research Objectives
- Experimentally test the dilution effect hypothesis that greater host species richness can reduce spread of generalist pathogens.
- Mechanistically examine the conditions for the dilution effect to operate, particularly the roles of host species composition, pathogen spillover, and apparent competition.
- Compare the effects of host community richness and composition on the spread of vector-transmitted and directly transmitted pathogens.
Study Species
- Avena fatua (Wild Oats)
- Bromus tectorum (Cheatgrass)
- Digitaria sanguinalis (Hairy Crabgrass)
- Echinochloa crus-galli (Barnyardgrass)
- Lolium multiflorum (Italian Ryegrass)
- Panicum capillare (Witchgrass)
- Setaria lutescens (Pearl Millet)
- Setaria viridis (Green Bristlegrass)
Collaborators
- Sunny Power- Cornell University
An experimental field at Cornell University, with aphid cage mesocosms in the
foreground and successional species including goldenrod in the background.
This project continues my collaboration with my postdoc advisor Sunny Power. We are using field and controlled environment experiments at Cornell to test the effects of host diversity and species composition on the spread of generalist pathogens. As well as continuing to work with the aphid-transmitted barley yellow dwarf virus (BYDV), we are also are beginning to work on barley stripe mosaic virus (BSMV). BSMV is directly transmitted through plant to plant contact – leaves of infected plants shed virions, which rub off onto leaves of adjacent plants. As with our other studies of virus dynamics in annual grass assemblages, we see this work as providing an experimentally tractable model system for the study of potentially general feedbacks between host community structure and pathogen spread. This project is funded by the NSF Ecology program through 2009.
