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Research in the lab is motivated by the need for a mechanistic understanding of the biotic and abiotic effects driving spatiotemporal patterns in insect or disease dynamics, with a goal toward mitigating impacts to agricultural, natural, and urban ecosystems. Our research draws from concepts and methods in invasion biology, plant-insect interactions, disease ecology, quantitative ecology, and regulatory entomology. This typically involves asking basic ecological questions, using experiments or field surveys complemented by a bit of modeling, in applied biological systems
The following sections highlight some recent projects
Pierce's disease (PD) resurgence in North Coast vineyards
PD has affected grape production for as long as grapes have been produced commercially in California. Yet the incidence of disease is highly variable in space and time. In vineyards along the North Coast of California, PD prevalence is typically modest, but occasional severe epidemics have occurred. In recent years grapegrowers in the region have noticed not only uncharacteristically high disease incidence, but also unusal patterns in where cases of disease are being found within a vineyard block. Working with collaborators at UC Berkeley and cooperative extension offices in Napa and Sonoma Counties, we have been documenting spatial and temporal patterns in vector abundance and PD prevalence at more than 30 sites to understand what may be driving the current epidemic. As part of this work, we are evaluating potential triggers such as a novel pathogen strain, a novel (or misunderstood) vector, and the potential role that recent climatic conditions may have played
ACP management in urban and nursery settings
The Asian citrus psyllid (Diaphorina citri; ACP) and huanglongbing (HLB) have proven to be highly invasive throughout the Americas. Following the first detection of ACP in a residential area of Southern California in 2008, it spread rapidly throughout the region - particularly in urban and suburban environments. The first case of HLB was confirmed in 2012, and subsequently has become widespread in several residential areas of Southern California. In addition to studies of the what contributed to ACP's success in Southern California, we have been conducting research on how to manage it, particularly in residential and nursery citrus. This has included studies of the effectiveness of a voluntary residential treatment program, how to mitigate the risk of green waste contrubuting to ACP spread, and optimizing chemical control in nursery citrus
Geospatial analysis of insect invasions
State and federal regulatory agencies often conduct large-scale monitoring programs to track the spatial extent of plant and animal invasions. This information is typically used to define regulatory response, such as what areas to quarantine or prioritize for treatment. We have been repurposing these robust datasets, leveraging them to gain additional insights into the climatic, landscape, and anthropogenic factors driving invasion dynamics. For example, we've used a combination of geospatial tools and habitat suitability modeling to reconstruct the successful eradication of the European grapevine moth (Lobesia botrana), quantify the strength of urban spillover by the Asian citrus psyllid (Diaphorina citri) into commercial citrus groves, and generate predictions for the risk of establishment by a moth pest complex in vineyards along the West Coast
Field validation of risk modeling
Species distribution models or other correlative habitat suitability models are often used in decision making regarding responses to invasive species, as a reflection of relative risk of introduction, establishment, or spread. Yet, the predictions from these risk models are rarely validated in an indepdent way to gauge their explanatory power. We have been conducting field surveys to evaluate the continued spread in Northern California of the invasive vine mealybug, Planococcus ficus, to confirm that geospatial modeling based on an extensive collection of trapping records captures adequately P. ficus invasion dynamics
Associational effects of a shared herbivore
Multiple invasive species can interact with each other to exacerbate impacts to native flora and fauna. One mechanism by which this often occurs is via associational effects, wherein one plant species affects another via a shared herbivore or pathogen. We have been studying the effects of an invasive annual plant, Sahara mustard (Brassica tournefortii), and invasive herbivorous stinkbug, Bagrada hilaris, to understand whether associational effects explain observed declines in native plants - including the perrennial shrub, four-wing saltbush (Atriplex canescens)
100 Chapman Hall
Department of Entomology
University of California
Riverside, CA 92521
(951) 827-2246
