Cheryl A. Wilen

Field Trials Measuring the Effects of Ultraviolet-Absorbing Greenhouse Plastic Films on Insect Populations

Abstract Field studies were conducted to compare insect population levels in greenhouse crops covered with plastics that block the transmission of UV light in two wavelength ranges. Crops grown in greenhouses under a plastic that blocked UV light at wavelengths of 380 nm and below had lower numbers of aphids and thrips compared with a plastic that blocked UV light at wavelengths of 360 nm and below. This is consistent with the results found for thrips in previous studies using small, completely enclosed tunnels with no plant material. The effects were not as dramatic in the commercial greenhouses, perhaps due to unfiltered light entering through the open sides of those greenhouses. There was no reduction in greenhouse whitefly, Trialeurodes vaporariorum Westwood, populations under the <380 UV-absorbing plastic compared to <360 nm UV-absorbing plastic in these field trials. This is inconsistent with results found in small, completely enclosed tunnels, where sticky traps caught a significantly higher proportion (95 ± 2%) of released greenhouse whiteflies inside tunnels covered with <360 nm absorbing plastic compared with the <380 nm absorbing plastic. The results of these studies suggest that the type of greenhouse plastic used in a structure can affect population levels of some insect species, and may be useful tools in developing integrated pest management programs for insect management. The design of the greenhouse and amount of unfiltered light that enters the system appear to be important factors in determining the level of effect.

Gearing up to support urban farming in California: Preliminary results of a needs assessment

According to the United States Census, California is the most urban state in the nation. Although there are many outstanding examples of urban farms in California, in general, urban agriculture (UA) has been slower to gain momentum here than in some other states with large urban populations. Over the past several years, urban agriculture’s popularity in California has begun to escalate, with strong emerging interest in San Francisco, San Jose, Oakland, San Diego, Los Angeles and other metropolitan communities. One challenge for urban farmers and municipal decision makers engaged with UA in California has been limited availability of relevant information and technical assistance. A new project team at the University of California Cooperative Extension, part of the Division of Agriculture and Natural Resources (UC ANR) is working to develop web-based educational resources that will be grounded in a needs assessment that is currently underway. The needs assessment includes a literature review, an internal survey of UC ANR personnel, and community clientele interviews. This paper will report on preliminary findings and analyses of the needs assessment, particularly how UC ANR personnel are engaged with UA, and what tools they think would best serve urban farmers. We suggest implications for those involved with UA, such as personnel of land-grant universities, local governments and non-profits seeking to address the needs of urban farmers in an environment of constrained resources.

Practical Pest Management Strategies to Reduce Pesticide Runoff for Argentine Ant (Hymenoptera: Formicidae) Control

ABSTRACT The purpose of this study was to involve pest management professionals in the design of application techniques and strategies that would be efficacious and also reduce insecticide runoff. Our study involved measuring both the efficacy of treatments for the Argentine ant, Linepithema humile (Mayr), and the concurrent runoff of fipronil and pyrethroids. Two collaborating companies used low-impact protocols for controlling ants while minimizing runoff. Protocol 1 involved bimonthly treatments, while Protocol 2 was monthly. Both protocols involved an initial treatment with a fipronil spray around the foundation. At the garage door—driveway interface, the fipronil application was done as a pin stream for Protocol 1, and as a crack and crevice application in the expansion joint near the garage for Protocol 2. Protocol 1 replaced most pyrethroid sprays with bifenthrin granules placed around bushes and away from the driveway. For the next treatment on day 63, Protocol 1 also included cyfluthrin spray treatments around the house foundation and crack and crevice applications around the edge of the driveway. For the first treatment in Protocol 2, the fipronil spray was supplemented with spot treatments of cyfluthrin. For subsequent Protocol 2 treatments, botanical insecticides were applied. For weeks 1 and 2 posttreatment combined, Protocol 1 had significantly higher reductions in ant numbers compared with Protocol 2. Thereafter there were no significant differences between the protocols. Runoff of bifenthrin from the granules used with Protocol 1 was much lower than in previous trials involving bifenthrin sprays. Day 1 fipronil runoff for Protocol 2 was significantly lower than that for Protocol 1. This difference may be because of the crack and crevice application applied in Protocol 2. Cyfluthrin runoff was minimal for Protocol 2, which involved spot treatments to supplement the fipronil on day 1, or the botanical insecticides for subsequent treatments. Protocol 1 had a large peak of cyfluthrin runoff at day 63 corresponding to their house and driveway treatments.