Finding Better Ways to Battle Bugs

Lily CalderwoodLily Calderwood

University of Vermont

SARE grant: Evaluation of flowering cover crops as an IPM tool in Northeastern hop production (2012)

Where she is now: Commercial Horticulture Educator, Cornell Cooperative Extension

When it comes to managing pests, many growers are working to find ecological strategies that reduce pesticide use and favor beneficial insects and pollinators. As desirable as this approach is, it also takes greater understanding of pests, crops and the local environment.

So, while a graduate student at the University of Vermont, Lily Calderwood sought to provide growers with the information they need to implement ecological pest control strategies, by studying how the state’s expanding hops industry could reduce pesticide use through beneficial insects and flowering cover crops. She received a 2012 SARE Graduate Student grant to evaluate how cover crop plant species diversity and flowering affect the number of pest and natural predators in hop yards.

Calderwood worked in an Alburgh, Vt., hop yard with established cover crop plots. She identified beneficial and pest arthropods, correlating them with cover crop development, hop yield and hop quality. After identifying three major pests—two-spotted spider mites, potato leafhoppers and hop aphids—she also identified their natural enemy groups. Calderwood discovered that a large, established stand of unmowed red clover could be used in hop yards as a trap crop for potato leafhoppers.

After finishing her graduate student project, Calderwood reported that her SARE award was integral to her doctoral research. “The hop cover crop project would not have continued into its second and third years without SARE’s support,” she says.

Now a senior commercial horticulture educator for Cornell Cooperative Extension, Calderwood gives back to the program that was important to her by having served on the Northeast SARE technical committee that reviewed 2016 Graduate Student grant proposals. In this role, she provided the perspective of someone who has been through the process. “It is a great program, and I’m glad to be part of it,” she says.


Calderwood reached hundreds of current and potential hops growers with her findings, including a presentation at the state’s 2015 Hop Conference. Out of 31 farmers who responded to a survey, 20 indicated that their knowledge of insect pest identification and scouting had increased, and half are actively scouting for the three major pests. Six of the respondents are currently spraying insecticides and are very interested in learning more about clover as a trap cover crop.


Cover image of hops insect cheat sheetCalderwood published the following University of Vermont fact sheets and field guides during the course of her research:

She published the following journal article:

L. B. Calderwood, S. A. Lewins, H. M. Darby. Survey of Northeastern Hop Arthropod Pests and Their Natural Enemies. Journal of Integrated Pest Management, 2015; 6 (1): 18 DOI: 10.1093/jipm/pmv017

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