Conditional Vector Preference Aids the Spread of Plant Pathogens: Results From a Model

Abstract

Vectors of several economically important plant viruses have been shown to feed or settle preferentially on either infected or noninfected host plants. Recent research has revealed that the feeding or settling preferences of insect vectors can depend on whether a vector is inoculative (carries the virus). To explore the implications of such changes in vector preference for the spread of the pathogen, we create a basic model of disease spread, incorporating vector preferences for infected and noninfected plants dependent on whether the vector is inoculative. Previous modeling work assumed that vector preferences remain unchanged with vector infection status and showed that vector preference for infected host plants promotes disease spread when infected hosts are rare, whereas preference for noninfected hosts promotes spread once infected hosts become abundant. In contrast, our model shows that a change in preference following acquisition of the pathogen can increase pathogen spread throughout the epidemic if noninoculative vectors prefer infected plants and inoculative vectors prefer noninfected plants, as has been detected experimentally in two pathosystems. Our results show that conditional vector preference can substantially influence plant pathogen spread, with implications for agricultural and natural systems. Conditional preference as a component of virus manipulation of vector behavior is potentially more important for the understanding of plant disease spread than previously recognized.

Vector population growth and condition‐dependent movement drive the spread of plant pathogens

“…These results are consistent with those from the model by Roosien et al. (), that indicated that pathogen spread throughout an epidemic was enhanced when viruliferous vectors preferred healthy plants and nonviruliferous vectors preferred infected plants.…”

“…We observed that pathogen spread is slow when vectors prefer hosts that match their infection status (viruliferous vectors prefer infected hosts and nonviruliferous vectors prefer healthy hosts), and fastest when vectors prefer hosts with different infection status (viruliferous vectors prefer healthy hosts and nonviruliferous vectors prefer infected hosts). These results are consistent with those from the model by Roosien et al (2013), that indicated that pathogen spread throughout an epidemic was enhanced when viruliferous vectors preferred healthy plants and nonviruliferous vectors preferred infected plants.…”

“…August 2017 SPREAD OF VECTOR-BORNE PLANT PATHOGENS than life history (e.g., McElhany et al 1995, Sisterson 2008, Roosien et al 2013.…”

“…In their models, Roosien et al. () added the inoculative status of the vector and asked what happens if vector preference changes once it acquires a virus. Model results indicated that pathogen spread throughout an epidemic was enhanced when nonviruliferous vectors preferred infected plants and viruliferous vectors preferred healthy plants.…”

“…Sisterson (2008) decomposed preference behavior into orientation vs. settling and feeding, and found that these two aspects of preference for healthy or infected plants can differ in their effects on pathogen spread. In their models, Roosien et al (2013) added the inoculative status of the vector and asked what happens if vector preference changes once it acquires a virus. Model results indicated that pathogen spread throughout an epidemic was enhanced when nonviruliferous vectors preferred infected plants and viruliferous vectors preferred healthy plants.…”