Association of plant pathogen vectors and vector-borne plant pathogens with landscape composition: a meta-analysis.

Previous studies investigating the relationship between landscape composition surrounding a crop, and either plant pathogen vectors or vector-borne plant pathogens in the crop, have not observed consistent relationships, and no quantitative synthesis of the current literature has been conducted. We conducted a meta-analysis of 289 published effect sizes from 28 studies to better understand the relationships between landscape composition and plant pathogen vectors or vector-borne pathogens, while considering a series of biological, ecological, and environmental factors that may contribute to variation in the relationships. We found that vector and vector-borne pathogens were positively associated with landscape composition metrics, including the percentages of the landscape surrounding the study areas that were crop, non-crop, and natural habitat but not with habitat diversity. Vector host plant specialists exhibited a significant positive association with various landscape composition metrics, while host plant generalists did not, supporting the idea that specialists are more dependent upon specific host landscape features, whereas generalists have hosts that are generally more abundant across various landscapes. Measurements of both abundance and incidence of pests exhibited significant positive associations with landscape composition metrics. For both persistent and non-persistent pathogens, the positive association between pathogens and landscape composition became stronger at larger spatial scales (500 to 10,000 m). This meta-analysis demonstrated that increasing the percentage of crop, non-crop, or natural habitat within a landscape can increase vectors or vector-borne pathogens in the crop. However, the specific landscape feature that contributes to increased pest abundance or incidence will depend on the crop-pest system.