People

As an agricultural entomologist, I conduct research to reduce arthropod impacts on crop production while maintaining farm profitability. My approach is rooted in the fundamentals of integrated pest management (IPM) and the belief that we can leverage our scientific understanding of crops, organisms, and the environment to develop practical and cost-effective pest management strategies for growers. I’m particularly interested in the development and evaluation of biological controls with an emphasis on plant-insect interactions, landscape ecology, insect movement, and regional population dynamics. I also conduct work with chemical controls, where my goal is to design programs that minimize the human and environmental impacts of insecticide use in agriculture.

Broadly, my research focuses on biological control and insect vector ecology. More specifically, I conduct research on (1) the role of biodiversity in conservation biological control, (2) natural enemy introductions to improve biological control of invasive pests, and (3) insect vectors of plant pathogens. Some of this work has been carried out to address grower interest in integrated management (habitat diversification studies) while the other elements are in response to newly emerging problems with pests and diseases.

My research programs all utilize a combination of field, greenhouse and laboratory studies to evaluate the underlying mechanisms that drive on-farm processes in order to improve our understanding of crop pests and pathogens. Collaboration with growers and UCCE farm advisors is paramount in all of my programs. Their input helps me to pursue relevant research questions and ultimately develop better management strategies. In a similar way, involvement of other UCCE specialists and university scientists is important to address problems that are cross-disciplinary in nature.

Improving Biological Control of the Virginia Creeper Leafhopper in North Coast Vineyards (2013-present)

Project Website: http://ucanr.edu/sites/vclh/

Organic growers in Mendocino and Lake County have recently been experiencing serious outbreaks of the Virginia Creeper leafhopper (Ciccadellidae: Erythroneura ziczac), an invasive pest that established in this region around 2011/2012. Outbreaks are primarily due to (1) lack of biological control and (2) need to adjust the timing of chemical controls. Surveyed vineyards across northern California to identify potential Anagrus spp. parasitoids of E. ziczac. A candidate parasitoid (Anagrus daanei) has been identified in the Sacramento Valley. Initial efforts to collect, augment and release A. daanei from the Sacramento Valley into Mendocino County vineyards have been successful and led to increased parasitism of E. ziczac. We are now in the process of carrying out a program to mass release A. daanei in vineyards throughout Mendocino and Lake County. Efforts to identify and import parasitoids from other regions of California have been complemented by (1) grower outreach and education and (2) research to improve the efficacy and timing of OMRI-approved chemical control products.  

Insect Vectors of Grapevine Red Blotch-associated Virus (2015-present)

There are many unknowns surrounding the newly identified Grapevine Red Blotch-associated Virus (GRBaV), which can lead to reduced fruit yield and quality due to delayed ripening and other changes in the vine that effect productivity. While many claim to have observed movement of this virus throughout the vineyard, no vectors have been identified to date. We are currently conducting virus transmission experiments with a number of insects commonly found in vineyards. We are also conducting broader vineyard insect surveys to identify novel and untested vectors.  

Influence of Landscape Diversity on Biological Control of Vineyard Leafhoppers (2010-2013)

On-farm habitat diversification can lead to reduced pest populations/impact and enhanced natural enemy populations/impact. At the same time, the area and composition of natural habitat surrounding an agroecosystem can also influence biological control of crop pests. Biological control of the Western grape leafhopper (E. elegantula) was evaluated in vineyard monocultures that were situated across a gradient of landscape diversity in Napa and Sonoma County. Increased parasitoid abundance at high diversity sites led to increased biological control of E. elegantula. At the same time, E. elegantula populations were also reduced at sites with lower crop vigor, indicating that a combination of top-down and bottom-up factors work in conjunction to influence pest populations.  

Flowering Cover Crops to Enhance Biological Control in Vineyards (2008-2014)

Worked in collaboration with numerous wine grape growers in Napa and Sonoma County to develop and evaluate the use of summer flowering cover crops to enhance biological control of vineyard leafhoppers. Focal pest was the Western grape leafhopper (Ciccadellidae: Erythroneura elegantula) and its key parasitoids Anagrus erythroneurae and Anagrus daanei. Flowering cover crop program included the use of Phacelia tanacetifolia, Ammi majus and Daucus carota. Flowers are sown in the fall and sequentially bloom over the grape growing season (approx. April - October).