OOS 19-4 - Insect pests in vegetable gardens: Documenting damage and delivering results

Wednesday, August 9, 2017: 9:00 AM
Portland Blrm 253, Oregon Convention Center
David Lowenstein, Department of Horticulture, Oregon State University, Corvallis, OR

As food production for personal use and commercial sale becomes integrated into the urban landscape, there is a need to examine pest management compatible with the small scale of production. Newer commercial farms as well as home gardeners would benefit from data-driven research. However, land-grant insitutions and extension offices do not always offer information applicable to urban agriculture. I describe two projects that evaluated the potential for biological control and that educated gardeners and growers about emerging pests. First, I investigated predator-prey interactions in Chicago, IL urban agriculture and the effect of garden size and surrounding landscape on predation and parasitism of cabbageworms. Second, I monitored the Portland, OR metropolitan area for the distribution of Trissolcus japonicus, an Asian egg parasitoid wasp, which parasitizes Halyomorpha halys, a nuisance pest in cities and an economically damaging pest in fruit crops and vegetables. Participating sites in Chicago, IL were recruited through online listservs and partnering with a local agriculture policy group, while participants in Portland, OR were recruited through Master Gardeners and Extension. I describe efforts and challenges in implementing projects, collecting ecologically useful data, and delivering research-driven information to growers.


In Chicago urban agriculture, I identified at least 18 parasitoid families including several known to parasitize cabbageworm eggs and larvae. There was evidence of cabbageworm mortality from natural enemies in urban farms and residential gardens. In the Portland, OR study, I did not detect T. japonicus in any of the sample sites. Both projects provided valuable information on urban insect communities, and results were disseminated through grower field days, a research seminar on urban agriculture, and summaries of results tailored to each participant. Sample site recruitment was easier in Oregon due to the presence of well-established Master Gardener and extension programs. The main challenges associated with project success included recruiting sample sites, communicating regularly with participants, and neglected maintenance of sample sites. 10-15% of participating sites dropped out after the project started or failed to follow the instructions provided. Cultivating collaboration with growers is essential for success in urban agriculture. Partnerships with private and public agencies will simplify project planning and assist researchers in implementing studies relevant to urban agriculture stakeholders.