Providing Farmers with New Brassica Species - Management Options of Flea Beetles for Expanding Markets in Mass. - Conn.

2003 Annual Report for LNE01-142

Project Type: Research and Education
Funds awarded in 2001: $135,632.00
Projected End Date: 12/31/2005
Matching Non-Federal Funds: $83,150.00
Region: Northeast
State: Massachusetts
Project Leader:
Frank Mangan
University of Massachusetts

Providing Farmers with New Brassica Species - Management Options of Flea Beetles for Expanding Markets in Mass. - Conn.


Over the course of four years, over fifty farmers in Massachusetts and Connecticut will be given seed, production, and marketing information for new brassica species. Research on flea beetle management, both replicated trials at two research stations and on cooperating grower’s fields, will be conducted. All cooperating growers will be visited on a regular basis during the growing season to address production and flea beetle management issues. The production and marketing information created will be disseminated via twilight meetings, extension and professional talks, extension and professional publications, and on the web.

Objectives/Performance Targets

Performance Targets:
Of the 50 farmers who participate in testing new brassica species for their markets, 25 will have added at least one new species into their rotation. Twelve farmers will participate in on-farm trials for flea beetle management, and seven will incorporate one or more of these management options. Flea beetle management will have improved for these farmers, either allowing them to grow brassica crops earlier in the spring than they did before, or reducing flea beetle damage so that less product is lost.


New Brassica species:
1. Spring 2001: Contact 50 farmers. Over 50 farmers were invited to participate in this project.
2. Summer 2001: Brassica given to 40 farmers. Forty growers in Massachusetts and Connecticut were given up to $50/farm of brassica seeds to grow and market at their farm.
3. Fall 2001/ Winter 2002: Interview 40 cooperating growers and invite to a grower meeting. At the end of the field season all cooperating growers were interviewed on their experiences with all aspects of production and marketing of these crops. A meeting was held at the Sturbridge Host Hotel in Stirbridge Mass on February 7, 2002. We had a total of 30 people present at the meeting, including 22 cooperating growers. The meeting was held from 10:00 Am to 3:00 PM. We discussed all aspects of the project with the growers.
4. Spring 2002: Give brassica to 40 growers. Thirty-eight growers in Massachusetts and Connecticut were given up to $50/farm of brassica seeds to grow and market at their farm.
5. Winter 2003: Interview growers and invite to grower meeting. At the end of the field season all cooperating growers were interviewed on their experiences with all aspects of production and marketing of these crops. A meeting was held at the Valley Laboratory in Windsor, Connecticut, from 10 a.m. to 3 p.m. on January 9, 2003. A total of 15 people attended. Eight were participating farmers. We discussed all aspects of the project with the growers.

Flea beetle research
1. Summer 2001. 1. Replicated flea beetle(FB) trials in MA and CT. FB monitored on 6 farms. Trials conducted (and reported on in previous report) and flea beetle monitored on cooperating farms.
2. Fall of 2001/winter 2002. 2. Present results to participants and to other growers in meetings and publications. Identify promising management options. Report given to coopering growers at meeting held in Sturbridge, Mass. on February 7, 2002.
3. Summer of 2002. Repeat replicated FB trials. Conduct on-farm FB mgt trials on 12 farms. Brief summary of work and plans on flea beetle trials is included.
4. Winter of 2002/2003. Present results to participants and other growers. Results presented to cooperating growers at meeting held on Valley Laboratory in Windsor, Connecticut on January 9, 2003. A second meeting was held in Westborough Massachusetts on March 27, 2003 with a focus on flea beetle management. Fifteen growers were present.
5. Spring/summer of 2003. Seven growers participated in on-farm research during this field season. This was lower than the 12 cooperating growers we proposed to work with due to the inability to get enough growers interested in participating in this research.

Impacts and Contributions/Outcomes

Outcomes of flea beetle research in 2003:

Flea beetle pesticide trials
Since 2001, four sets of pesticide trials have been performed to evaluate a variety of pesticides for use against flea beetle damage on brassicas (particularly leafy varieties) for both organic and conventional growers. Results from our trial in 2003 were consistent with earlier trials. The use of row cover or carbaryl (Sevin XLRPlus) produced plants with the least damage at harvest. Spinosad (in either conventional or organic formulations) shows promise as a new pesticide for use on brassica greens. Another product of interest is the systemic pesticide thiamethoxam (Platinum) which, while not labeled for use on brassicas yet, has been effective in our field trials at reducing damage to plants during the first two to three weeks of growth. Pyrethin (Pyganic 4EC), another organic product, provided no reduction in flea beetle damage compared to controls.

Flea Beetle Ecology
Based upon season-long dissections and cage feeding studies with field-collected beetles, we now have evidence that flea beetles on brassicas have two generations in Massachusetts. Eggs were present in adult females from mid May until late August. Our results support the hypothesis that a summer generation of adults emerge in late July and early August and that at least some of these adults produce eggs that will result in a second emergence in the fall. Understanding of the life cycle and when to expect a rise in adult numbers and feeding will help growers use rotation and other controls more effectively.

On-Farm trials
In 2003, five growers conducted a total of seven replicated experiments in beds of arugula greens that were divided into small plots. Five experiments compared row cover and/or weekly applications of spinosad (Entrust) with uncovered, unsprayed arugula. This material was of particular interest to these organic farmers because it was newly approved by the NOP and has shown efficacy in our pesticide trials. One grower compared use of eight-foot water tubes to soil-filled poly bags for weighting the edges of row cover, especially at the ends of raised beds. One compared several row cover weights during midsummer to evaluate both flea beetle damage and crop growth. In addition, one grower used two organic insecticides (Entrust and Pyganic) on larger plantings of succession-planted greens.

Results: There were no statistically significant differences between uncovered, non-sprayed controls and Entrust® treatments in any farm trials where pesticide was tested. However, flea beetle feeding injury was reduced in Entrust® plots. Both controls (4 of 4 trials) and sprayed plots (3 of 4 trials) had significantly higher levels of feeding injury than plots protected with row cover.

Physical barrier methods employing row cover proved to be highly effective. However, based solely on the results from the various participating sites we would conclude that repeated treatments of Entrust® have at best a minimal impact on flea beetle management for small-scale growers of arugula, and perhaps other brassica crops. Several confounding factors may have reduced efficacy of sprays in these trials, including frequent heavy rains, and the close proximity of sprayed and unspray plots, which allows re-invasion into sprayed plots.

The use of flexible water-filled tubing was a practical and cost-effective method of anchoring row cover where planting surfaces were particularly irregular, as with raised beds. Tubing, like anchor bags, can be fairly easily moved for cultivating, and provides a somewhat improved seal between the soil surface and row cover. Soil bags may be easier to manage and gave nearly equal control when placed to provide a tight seal.

All row covers of various weights provided significant protection from flea beetle feeding compared to control plots. Among the three row cover weights tested (heavy, medium, and light/non-heating type) there were no significant differences in the degree of feeding injury. Concerning yield the reverse was true – accumulated plant biomass was substantially lower under the conditions created by heavy row cover. Light row cover (P10) had the highest biomass at harvest.

Grower’s comments in surveys included discoveries that were not specifically targeted in the trials. One grower was pleased to discover that after several years of not planting brassicas before the end of July, his flea beetle populations are now so low that he can successfully grow arugula in June. Another had not believed that row cover would work on her farm and now is excited to see that it works very well and that lightweight cover produces better quality in the heat — which will enable her to grow greens all summer. Another realized that he can use either water tubes or soil bags to make his row covers more effective, especially if he pays close attention to the ends of the rows. The growers who use both Pyganic and Entrust on a larger scale concluded that Pyganic is more effective; a result which is the opposite of what was found in the UMass trials.

A total of 320 growers and approximately 60 researchers were informed of the results of flea beetle research through educational programs (see meeting list). Multiple articles on flea beetle management reached 400 subscribers of the UMass Vegetable Newsletter as well as visitors to the website.

During winter 2003, 20 growers attended two roundtable meetings with researchers and discussed flea beetle management.

General summary

Overall, results show consistent effectiveness of row covers. With row cover, control of flea beetle and high yield can be optimized by ensuring a tight seal with water tubes or soil filled bags, and by improving growth conditions in midsummer by using lighter-weight row cover. Insecticidal control is consistently good with Sevin, and for organic growers spinosad (Entrust) is promising although results are inconsistent. Better understanding of the flea beetle life cycle will help growers use these tools, along with rotation, more effectively.


Kim Stoner

Connecticut Ag. Experiment Station
Ruth Hazzard

UMass Extension