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Sustainable pest management requires growers and regional land managers to consider the relationships among pest management practices, pest and natural enemy communities, crop loss, and multi-scalar habitat complexity. However, the causal links among these variables, in particular potential interactions between landscape and local-scale habitat complexity, remain underexplored. In the context of organically managed strawberry crops in California’s Central Coast, we tested the independent effects of landscape and local habitat complexity gradients on arthropod communities and crop loss using a piecewise structural equation model (PSEM). We found that landscape-scale woody habitat proportion indirectly decreased crop loss through its positive effect on natural enemy abundance, while grassland proportion had the opposite effect due to its association with an important strawberry pest (Lygus spp.). We detected a pattern suggesting that on-farm diversification practices are most effective at reducing crop loss at an intermediate level (26%) of woody habitat proportion. Both organic-compliant insecticide application and tractor vacuuming negatively impacted natural enemies, and therefore had qualified effects on crop loss. Our study shows the key roles of native woodlands and natural enemy communities in reducing crop loss and highlights the importance of managing habitat complexity at both landscape and local scales.

California's Central Coast rose to national food safety prominence following a deadly 2006 outbreak of Escherichia coli O157:H7 that was traced to spinach grown in this intensive agricultural region. Since then, private food safety protocols and subsequent public regulations targeting farm-level practices have developed extensively, aiming to avert future foodborne illness crises. However, amidst sweeping reforms in prescribed best practices for food safety, growers were pressured to take precautionary approaches to control pathogenic contamination—suppressing wildlife near fields, removing habitat, restricting biological soil amendments (e.g., compost, manure), and most recently, chemically treating irrigation water—that may generate negative unintended consequences for environmental and social sustainability. We synthesize socio-ecological data from three qualitative, interview-based studies to examine grower perceptions and experiences of food safety reforms in California's Central Coast region and explore the effects of food safety regulations on environmental and socio-economic sustainability. We identify three disjunctures between food safety requirements and farming realities in practice: (1) Growers perceive that some food safety practices legitimately mitigate risk, while others fail to reduce or even accentuate risk; (2) Food safety requirements can create contradictions in the co-management of food safety and environmental sustainability; and (3) Food safety requirements may foster impediments to regional food systems socioeconomic sustainability. We argue that these disjunctures warrant changes in food safety policy, implementation, and/or food safety education. We provide concrete suggestions for shifting the focus of food safety reform away from the narrow surveillance of individual grower compliance and toward an integrated perspective on regional risk, vulnerability, and resilience.

Fine-mesh exclusion netting is a potential alternative to organic and conventional insecticide application to control numerous pests of fruit crops. We tested whether fine-mesh exclusion netting would reduce pest abundance and increase marketable yield compared to organic spinosad insecticide sprays in an organically managed blackberry field. At the completion of flowering, we covered blackberry rows with fine-mesh exclusion netting (ProtekNet) and treated alternating rows with an organic spinosad insecticide (Entrust™). Fine-mesh exclusion reduced green June beetle (Cotinus nitida Linnaeus) and bird presence and marginally reduced Japanese beetle (Popillia japonica Newman) presence on blackberry canes compared to organic spinosad insecticide treatment. Exclusion netting reduced the capture of spotted-wing Drosophila (Drosophila suzukii Matsumara; “SWD”) in baited traps in the fourth week of exclusion and reduced the overall number of SWD adults emerging from harvested blackberry fruits. Marketable yield in the fine-mesh exclusion treatments was two times higher than the organic spinosad insecticide treatment. These results suggest that fine-mesh exclusion netting is a functional pest control alternative to insecticide treatment for organic blackberry production.