Phylogenetic escape from pests reduces pesticides on some crop plants

Abstract

Pesticides are a ubiquitous component of conventional crop production but come with considerable economic and ecological costs. We tested the hypothesis that variation in pesticide use among crop species is a function of crop economics and the phylogenetic relationship of a crop to native plants because unrelated crops accrue fewer herbivores and pathogens. Comparative analyses of a dataset of 93 Californian crops showed that more valuable crops and crops with close relatives in the native plant flora received greater pesticide use, explaining roughly half of the variance in pesticide use among crops against pathogens and herbivores. Phylogenetic escape from arthropod and pathogen pests results in lower pesticides, suggesting that the introduced status of some crops can be leveraged to reduce pesticides.

Aboveground herbivory can promote exotic plant invasion through intra‐ and interspecific aboveground–belowground interactions

“…Importantly, the invasive and native plant species in this study are closely related and therefore have similar associations with above‐ and belowground biota (Pearse & Rosenheim, 2020; Wandrag et al ., 2020). In China, A. hygrophila only feeds on A. philoxeroides and A. sessilis in the field (Li et al ., 2017).…”

Pest pressure relates to similarity of crops and native plants

“…This is not unexpected, given the strong influence of local factors including environment; species richness of local plant communities; and variation in host range, abundance, and dispersal capabilities of arthropods and pathogens. This variation limits the value of these phylogenetic relationships in predicting local outcomes, as pointed out by the authors and others (1,2,4,10). In the context of agriculture, local effects on pest pressure and pesticide use are particularly strong and well documented (11).…”

“…Understanding fundamental ecological factors that motivate pesticide use on crops is a key knowledge gap that perpetuates this ongoing dependence on pesticides. Pearse and Rosenheim (1) study several general drivers of pest pressure and associated pesticide use in California, one of the most intensive agricultural production regions worldwide. Because of the immense crop diversity and accessible data about the pesticide inputs used on those crops, the authors are able use this complex agricultural system as a test bed to ask whether pest pressure and pesticide use on agricultural crops are related to the evolutionary distance between important crop plants and their native relatives growing in noncrop areas of California (1).…”

“…Pearse and Rosenheim examine economic crop value and evolutionary history to describe the numbers of arthropod pest and crop pathogen species affecting each crop in the study region. To do this, they investigate 93 major annual and perennial Californian crops (>600-ha average area) and link economic crop value, plant community ecology, and phylogenetic relationships to describe crop-specific pest pressure and associated pesticide use (1,6). Findings show that phylogenetic distance between crops and their closest relative in the native plant community was negatively associated with pesticide inputs (1).…”

“…To do this, they investigate 93 major annual and perennial Californian crops (>600-ha average area) and link economic crop value, plant community ecology, and phylogenetic relationships to describe crop-specific pest pressure and associated pesticide use (1,6). Findings show that phylogenetic distance between crops and their closest relative in the native plant community was negatively associated with pesticide inputs (1). This result suggests phylogenetic escape in which the number of arthropod pests species associated with a crop decreased with increasing phylogenetic distance between the crop species and their closest native relative in California.…”