Submitted to: Entomology Society of America Pacific Branch Meeting
Publication Type: Abstract Only
Publication Acceptance Date: January 15, 2006
Publication Date: February 15, 2006
Citation: Sisterson, M.S. 2006. Effects of vector preference for healthy or infected plants on the spread of a plant pathogen. Entomology Society of America Pacific Branch Meeting. Available: http//pbesa.prosser.wsu.edu/2006abs.pdf Technical Abstract: The glassy winged sharpshooter, Homalodisca coagulata, threatens grape production in California due to its ability to vector Xylella fastidiosa, the causal agent of Pierce's disease of grapes. Research priorities set out by the National Academy of Sciences include investigating the relative preference of H. coagulata for infected and healthy plants. Prior to initiating empirical research, a simulation model was used to investigate the conditions under which such preference could influence pathogen spread. The model investigated two types of preference, short and long range. With short range preference for infected plants insects spent longer periods of time on infected plants than healthy plants and with short range preference for healthy plants insects spent shorter periods of time on infected plants than healthy plants. The pathogen spread faster with short range preference for healthy plants than with short range preference for infected plants. With long range preference, insects preferentially moved to healthy or infected plants without the possibility of acquiring the pathogen during the discrimination phase. Long range preference for healthy plants slowed pathogen spread when few plants were infected, but accelerated pathogen spread when most plants were infected. In contrast, long range preference for infected plants accelerated pathogen spread when few plants were infected, but slowed pathogen spread when most plants were infected. The importance of including preference in the model was influenced by assumptions about insect population size, insect movement rate, and the initial number of inoculative insects. Thus, empirical studies must determine the scale at which preference operates (i.e., short or long distance) and evaluate other characteristic of the system including population size, movement, and pathogen load in the vector.