NNY On-Farm Trials Show Ground Barrier May Help Reduce Damage by Swede Midge

April 29, 2025; Antwerp, Cape Vincent, Essex, NY.  The Northern New York Agricultural Development Program (NNYADP) has announced the results of field trials producing the first commercial farm data and grower assessment of a new way to manage a destructive vegetable crops pest, the swede midge.

Swede midge is an invasive insect that causes significant economic damage in the brassica family of crops, including broccoli, kale, cauliflower, and Brussels sprouts. In 2024, Cornell Cooperative Extension Vegetable Specialists Elisabeth Hodgdon, Ph.D., and Christy Hoepting conducted on-farm field trials testing Hoepting’s theorized approach of using ground barriers over swede midge-infested soil to prevent the pest’s spring emergence.

“These Northern New York Agricultural Development Program-funded trials in 2024 produced the first season-long data and grower assessment of the use of a ground barrier for swede management. The data indicates that ground barriers can play a valuable role in suppressing the soilborne phase of swede midge, and may be especially useful for organic growers,” said Hoepting.

Growers participating in the trials at farms in Jefferson and Essex counties had experienced as much as 100 percent of crop loss to swede midge prior to the trials funded by the farmer-driven NNYADP.

Swede midge can be a season-long problem. The tiny fly lays eggs in the growing points of brassica vegetables. Larval feeding damages plants so they are unmarketable. The larvae overwinter in the soil to emerge the following spring and produce multiple generations until a killing frost.

Growers Appreciate Trial Results
At Chicory Hill Farm in Antwerp, silage tarp was deployed over ground where nearly 100 percent of the broccoli crop was lost to swede midge in 2023. In 2024, the tarp was applied from mid-April to July 22, 2024. No swede midge damage was recorded in June, but by fall damage was seen in cabbage, cauliflower, broccoli, and lacinato kale crops. Even so, farm owner Allen Funk said, “Even with the damage we saw in 2024, it was still less overall than that we experienced in 2023.”

Hodgdon notes, “It is not uncommon for swede midge traps to capture 100 to 200 midges per week. In 2024, trap captures in our field trials at all the participating farms did not exceed 50 midges.”

In 2023, swede midge damaged approximately 80-90 percent of the organically-grown kale crop at Riverside Farm in Cape Vincent. In 2024, the ground barrier trial there placed silage tarp over the past year’s infested kale bed from April into mid-July. Swede midge damage ranged from none in June to 32 percent in October with an increase of 44 percent mid-season in July.

“In the Cape Vincent trial, some of the kale plants appeared to have outgrown early swede damage, resulting in fewer symptoms in October versus July,” Hodgdon says.

For Riverside Farm owner Carly Basinger, “This trial showed us that using a ground barrier is one more practice we can use in an integrated pest management system.”

In Essex, organic vegetable producer Sara Kurak has battled swede midge for 10 years. In 2023, the pest damaged nearly 100 percent of the sprouting broccoli and approximately 10 percent of kale, mustard greens, and Brussels sprouts crops. From April to October 2024, Full and By Farm deployed landscape fabric over ground that had been infested with swede midge in 2023. Swede midge counts exceeded the established economic threshold of 7 males per week only twice. No crop damage was recorded in June, July, or the fall. The count peaked at only 8 percent in August.

“All three growers perceived the use of ground barriers as useful for managing swede midge as part of an integrated pest management program. In Essex, Sara also used floating row cover over most of her brassica crops to manage flea beetles during each crop cycle and so the impact of the ground barrier must be considered in tandem,” Hodgdon points out.

Research Now Expanding in NNY and Statewide in 2025
In Hoepting’s research, landscape fabric was slightly more effective than silage tarp for reducing swede midge damage, and, in trials measuring impact on swede midge emergence from soil following ground barriers application, landscape fabric resulted in greater suppression of midges versus silage tarp. This may explain the results at the Essex County farm that used landscape fabric versus the Jefferson County farms that used silage tarp.

With the foundation of the NNYADP project, Hoepting and Hodgdon secured new funding from the Northeast Sustainable Agriculture Research and Education program to continue the work with vegetable farms in Northern New York and expand on-farm demonstrations of the use of ground barriers for swede midge management statewide.

The complete report on the swede midge management research is posted as part of the NNYADP “Improving High Tunnel Production in Northern New York” report under About: Projects by Year 2024 at nnyagdev.org.

Funding for the Northern New York Agricultural Development Program is supported by the New York State Legislature through the New York State Assembly and administrated by the NYS Department of Agriculture and Markets.

The third year report of the NNYADP-funded Value of Manure report prepared by a team of Cornell Nutrient Management Spear Program (NMSP) researchers is posted here: https://nnyagdev.org/wp-content/uploads/2025/02/NNYADP2024ValueOfManureReportFINAL.pdf 

Click here to see today’s (o4/07/25) Morning Ag Clips posting of an NMSP article in which  Ag Clips, NNYADP Co-Chair Jon Greenwood comments, “Before joining (this project), I already believed in the research that was being done, especially with the challenges that are coming environmentally and the negative impact of nay-sayers when it comes to the value of manure. I think every farmer knows that manure has a value — but how do we put a number to that? A project like this shows that the value of manure is important.”

The on-farm research quantifies the value of manure applications. NMSP On-Farm Research Coordinator Juan Carlos Ramos notes in the article, ““Northern New York is an important dairy region in our state.”

Funding for this project and others is made possible by the support of the Northern New York Agricultural Development Program by the New York State Legislature through the New York State Assembly. The funding is administrated by the NYS Department of Agriculture and Markets.

The Adirondack Explorer recently posted an article  on the NNYADP-funded tree sap beverages research project results by writer Holly Riddle. Here’s a link to that story: https://www.adirondackexplorer.org/stories/sipping-on-sap-maple-producers-branch-out-to-tapping-other-trees.

See the full project report here.

Willsboro/Northern New York; March 6, 2025. Early results of field trials of hazelnuts, chestnuts, and cold-hardy pecans funded by the farmer-driven Northern New York Agricultural Development Program (NNYADP) to evaluate them as new commercial crops for regional farmers are now posted at www.nnyagdev.org.

The 3 nut crops and 4 high value fruit crops: juneberry, elderberry, honeyberry and aronia are part of the NNYADP’s “New Commercial Fruit and Nut Crops for Northern New York” project. The trial are hosted at the Willsboro Research Farm in Willsboro, New York.

Commercial growers in each of northern New York’s six counties: Clinton, Essex, Franklin, Jefferson, Lewis, and St. Lawrence are cooperating producers in the research.

American hazelnut and hybrid hazelnut varieties were planted at the Willsboro farm in 2023 and 2024, followed by three lines of chestnut in 2024, and cold-tolerant pecans added in the fall of 2024. These nut crops are nutritious foods, for example, hazelnuts are high in protein and oleic acid, a monounsaturated fatty acid.

According to the early results report, all three nut species established well with one of the American hazelnut seedlings producing the trial’s first nuts in April 2024.

The high-antioxidant, high-phytonutrient “super fruits” in the NNYADP-funded trials represent a significant economic opportunity through sales of fresh fruit, u-pick, and value-added products. For example, elderberry is a highly imported product into the U.S., indicating an opportunity to develop a locally-grown domestic market. Aronia fruit production in North America has grown into a multi-million dollar industry with several dozen unique value-added products.

The NNYADP established New York’s first juneberry nursery of commercially-sold and wild-collected varieties at the Willsboro Research Farm in 2013. Aronia plantings were added in 2017, honeyberry in 2018, and elderberry in 2021.

“With enough growing seasons now, we are now seeing the natural stressors that impact established crops and beginning to develop best practices for managing pest, disease, and climate-related impacts,” notes Willsboro Research Farm Manager Michael H. Davis, Ph.D.

In 2025, the research team is testing strategies to encourage regrowth after a spongy moth infestation in the juneberry commercial and wild-collected plots and in the honeyberry trial in 2022. The ornamental varieties of juneberry were not defoliated by spongy moth in 2022 and in 2024 flowered profusely.

Visiting Honeyberry Expert Offers Insight
In 2024 University of Saskatchewan Professor Robert Bors, Ph.D., a renowned honeyberry plant breeder, toured the NNYADP honeyberry plots at the Willsboro Research Farm. The trial experienced a marked fruit yield decline between 2021 and 2023. In 2024, yield rebounded with some varieties, but the low yield trend continued with lines with and without branch dieback.

“Dr. Bors suggested that low organic matter in the soil of the trial plots might be impacting productivity, and noted that the use of black landscape fabric weedmat might be causing damage to the honeyberry’s shallow root system on summer high heat days here,” Davis explains.

The 2025 research plan includes nutrient management applications to enrich the soil to encourage honeyberry plant growth and replaces landscape fabric with wood chip mulch for weed management.

Heavy rains in 2023 and 2024, Japanese beetles in 2024, and a fungus that thrives in wet soils and was identified in 2024 may all have played a role in poor vigor and branch dieback in the aronia trial planting in 2024. In 2025, the research team is adjusting irrigation management and applying milky spore powder for Japanese beetle management.

Elderberry growth slowed by heavy deer browsing in 2023 rebounded with protection measures installed in 2024. This young trial planting has not yet matured to produce fruit.

Project collaborators include SUNY Plattsburgh Biology Associate Professor and botanist Michael Burgess, Ph.D., Cornell University Horticulture Professor Marvin Pritts, and New England Interstate Water Pollution Control Commission Agronomist Myra Lawyer working with the Lake Champlain Basin Program.

The 2024 and previous years’ “New Commercial Fruit and Nut Crops for Northern NY” results reports are posted at www.nnyagdev.org. Updates on this NNYADP research are regularly presented at the annual Willsboro Research Farm Field Days and grower events held statewide.

Funding for the Northern New York Agricultural Development Program is supported by the New York State Legislature through the New York State Assembly and administrated by the New York State Department of Agriculture and Markets.