Page Banner

United States Department of Agriculture

Agricultural Research Service

Title: Effects of Insect Preference for Healthy or Infected Plants on Spread of an Inspect Vectored Plant Pathogen: Insights from a Model

Author
item Sisterson, Mark

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 17, 2007
Publication Date: January 1, 2008
Citation: Sisterson, M.S. 2008. Effects of Insect Preference for Healthy or Infected Plants on Spread of an Inspect Vectored Plant Pathogen: Insights from a Model. Journal of Economic Entomology 101: 1-8.

Interpretive Summary: Insects vector many important crop pathogens. Infection of a plant by a pathogen may make the plant more or less attractive to the insect vector. Thus, preference or aversion to infected plants is thought to effect pathogen spread. Simulation models can be used to help understand how insect preference for healthy or infected plants may influence pathogen spread. Previous modeling work has shown that such preference does indeed influence pathogen spread. However, interactions of insect preference with other important model parameters were not investigated. Simulations with and without insect preference for healthy or infected plants were compared under different assumptions about insect abundance, insect movement, and initial pathogen load. With low values of these three important parameters simulations with and without preference differed greatly. However, when values of these three parameters where high simulations with and without preference were similar. Thus, insect preference for healthy or infected plants may not always be helpful in explaining patterns of pathogen spread. The knowledge gained from this study will help researchers and funding agencies determine the characteristics of insect-vector-pathogen systems where knowledge of insect preference could be valuable in developing disease management plans.

Technical Abstract: 1. Insects vector many important crop pathogens. Infected plants may be more or less attractive to insect vectors. Previous models have shown that insect preference or aversion to infected plants can have important effects on pathogen spread. However, interactions with other key epidemiological parameters such as insect density, movement, and initial pathogen load have not been considered. 2. The effects of short- and long-range preference or aversion to infected plants were examined with a spatially explicit simulation model under different assumptions about insect density, insect movement, and initial pathogen load. 3. With short-range preference or aversion to infected plants, insects selected infected and healthy plants at the same rate, but spent longer or shorter periods of time on infected plants than healthy plants depending on their preference. With low insect density, movement, and initial pathogen load, pathogen spread was faster with short-range preference for healthy plants than with short-range aversion to infected plants. However, increasing insect density, movement, or initial pathogen load reduced the difference between simulations with and without short-range preference. 4. With long-range preference, insects remained on healthy and infected plants for the same length of time. However, when insects moved they preferentially selected healthy or infected plants depending on their preference. With low insect density, movement, and initial pathogen load, long-range aversion to infected 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. Increasing insect density, movement, or initial pathogen load reduced the difference between simulations with and without long-range preference. 5. Synthesis and applications. Short- and long-range preference or aversion to infected plants influenced pathogen spread. However, the importance of including either type of preference in the model depended on assumptions about insect density, movement, and initial pathogen load. Thus, knowledge of insect preference or aversion to infected plants will be more likely to help explain patterns of pathogen spread for systems that typically have low values for these parameters.

Last Modified: 7/23/2014
Footer Content Back to Top of Page