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Small, diversified farms have been increasing in number in western Washington State over the past decade. The proximity to significant urban markets and the favorable growing season in this region allows for increasing success of these farms to direct market to consumers through farmer's markets and consumer supported agriculture programs. Popular products for these farmers include salad greens (lettuces, mustard greens, arugula, spinach) and Brassica types (broccoli, cauliflower, cabbage, Brussels sprouts). <P>With the increasing number of certified organic farms within proximity to one another, pests can easily move from one farm to another through the entire season. One such pest that is causing a problem in Whatcom County and King County, Washington is the crucifer flea beetle (Phyllotreta cruciferae (Goeze)). This flea beetle will damage salad greens and Brassicas by chewing 1mm to 5mm or larger holes in the leaves, making the greens non-saleable and decreasing the survivability of Brassica seedlings. <P>This project will evaluate existing tools for flea beetle control in western Washington State and investigate new tools for these growers. This will be achieved by conducting research trials of at least two treatments of flea beetle control on each of 7 to 8 farms (4 in Whatcom County, and 3 to 4 in King County). <P>The existing tools to be evaluated are those that have been tried with varying levels of success in other regions of North America, such as Northeastern United States and California. One local grower has tried a control method and gained anecdotal evidence to its success. This method will also be demonstrated and tested for efficacy. <P>This research and extension (demonstration) project attempts to address the pest problem of the flea beetle on Brassica species and related plant types. By reducing the population of flea beetles on a crop, the amount of damage to the crop will be reduced, resulting in three potential outcomes: 1) the grower will produce a less damaged, more saleable product; 2) the grower will produce a product of saleable size in a shorter period of time; or 3) more plants will survive resulting in a larger volume of saleable product. <P>The research efforts proposed are to be conducted in two counties in western Washington; King and Whatcom. This separation of multiple plot locales will increase the likelihood of interest, support, and relevance to a broad segment of small, fresh market producers in western Washington. <P>The results will be shared with other Extension professionals and growers throughout the region through events such as the field days, presentations at the Washington Tilth Conference, and information on websites
Non-Technical Summary: Small, diversified organic farms in Western Washington State have been having increased difficulties in controlling the crucifer flea beetle on salad greens and brassica crops. While limited research on crucifer flea beetle control in organic systems has been done in California and northeastern parts of the United States and Eastern Canada; little research has been performed on organic control of the flea beetle in northwestern parts of the United States, including Washington State. This project will evaluate six methods of control for flea beetle on organic farms and demonstrate these methods to local growers during on-farm field days. <P> Approach: Seven to eight farms in Whatcom and King Counties will be involved in the research and demonstration of treatments for flea beetle control. Treatments include six methods of flea beetle control during the first year of the study. Treatments showing promising results will be tested again in the second year, along with new treatments that may be developed or discovered during the first year. A minimum of two treatments will be tested at each farm in each year of the trial. The six treatments of flea beetle control to be tested are: 1. The use of a floating row cover: A row cover cloth will be placed over the crop immediately following seeding or transplanting. This method is meant as a physical barrier to the flea beetle. 2. Growing weed or cover crop populations among desirable crop: A cover crop will be started before the commercial crop and grown alongside the desired crop. This crop may be planted in one of two ways: 1) between the rows of the desired crop, or 2) as one of the rows, such as one in every four rows planted. Alternatively, weeds may be left allowed to grow between and among plants in a row to add plant diversity and confuse the pest. 3. Using straw mulch between and among rows of desirable crop: The straw mulch would be placed between the rows of a seed sown crop such as salad greens and would be placed between the rows and within the row of a transplanted crop such as broccoli. 4. Living barrier crop between rows: A tall crop, such as asparagus or tall peas, would be planted in between rows of the desired crucifer crop. This trial will be set up across at least 4 rows of a certain crop with living barriers separating rows. 5. Trap cropping with Chinese Southern Giant Mustard around edges of plot: A trap crop of 'Chinese Southern Giant Mustard' will be planted around the edges of the target plot. This trap crop will be sown earlier to be at a more advanced developmental stage than the commercial crop making it more attractive to the flea beetle. The flea beetles will be vacuumed from the trap crop on a weekly basis to reduce flea beetle numbers. 6. Use of a flea beetle trolley to disturb and trap flea beetles: A simple machine designed to disrupt beetles from the crop and catch them on a sticky surface will be used. The trolley will be pushed along the crop during a period of flea beetle activity, between mid morning and mid afternoon. Once per week, the number of flea beetles caught on the trolley will be counted to monitor efficacy of the trolley. Each treatment will be tested in three replicated plots per farm. Three plots will also be used as control plots, with all the same except for no flea beetle control treatment used. Plots will be incorporated into a farmer's growing system, as a result irregular plot sizes may be used in some instances. Efficacy of each treatment will be measured in two ways: 1) by visual evaluation, and 2) by using yellow sticky cards to evaluate the number of beetles per treatment. Two field days per year will be held in each county (Whatcom and King) for growers to observe methods being tested and to learn the results of the trials.