Optimizing management of a new invasive species, swede midge, on small-scale organic farms

Project Overview

Project Type: Partnership
Funds awarded in 2015: $14,994.00
Projected End Date: 12/31/2016
Grant Recipient: Cornell Cooperative Extension Vegetable Program
Region: Northeast
State: New York
Project Leader:
Christine Hoepting
Cornell Cooperative Extension - Cornell Vegetable Program

Annual Reports


  • Vegetables: broccoli, brussel sprouts, cabbages, cauliflower, radishes (culinary), rutabagas


  • Crop Production: crop rotation, low tunnels
  • Education and Training: demonstration, extension, on-farm/ranch research, workshop, newsletter article
  • Farm Business Management: feasibility study, risk management
  • Pest Management: biological control, cultural control, field monitoring/scouting, integrated pest management, mulches - general, sanitation, traps
  • Production Systems: organic agriculture
  • Sustainable Communities: local and regional food systems, sustainability measures

    Proposal abstract:

    Swede midge (SM) is an invasive insect pest that is threatening the viability of organic production of Brassica crops in the Northeastern US.  SM is quite small (< 2 mm) and its damage difficult to identify, so it is commonly misdiagnosed.  (Figure 1-5) Currently, there are no organic methods that provide effective control of SM.  There is an urgent need to develop effective pest management tools and to conduct outreach/education to familiarize at-risk small-scale organic growers with SM diagnosis and best management practices to protect them from devastating SM outbreaks.  For this project, we will partner with 6 small-scale organic farms to gain tremendous insight into the population dynamics of SM as it relates to management practices via intensive pest monitoring, optimize the use of newly developed disruption tactics including insect exclusion netting and garlic oil repellant for managing SM on small-scale organic farms.  Through our educational and outreach efforts including on-farm demonstrations, informational website, newsletter articles and oral presentations, the majority of organic Brassica growers in the Northeast US will become aware of SM, be able to identify its damage and will be knowledgeable on how to manage this pest effectively.  This is the first major outreach program targeting organic growers, and we anticipate that it will launch several more projects that seek to reduce economic losses caused by SM to organic growers.  Ultimately, crop failures and economic losses caused by SM will no longer occur and the viability of the organic Brassica industry in the Northeast US will be sustained.

    Project objectives from proposal:

    Our objectives are to:



      1. Advance understanding of swede midge (SM) pressure and invasion on small-scale organic farms growing Brassicas as it relates to management practices.


      1. Optimize implementation of newly developed disruption tactics including insect exclusion netting and garlic oil repellant to manage SM in Brassicas on small-scale organic farms.


      1. Increase awareness of SM and knowledge of its management practices among at-risk small-scale organic Brassica growers.



     We will partner with 6 small-scale organic farms that have varying degrees of SM infestations.  Each farm will be a case study where we will monitor the SM population, trial disruption tactics and make management recommendations that are appropriate to the uniqueness of each farm.  Due to budget constraints, case studies will be conducted only in NY, which accounts for 79% of organic production of broccoli, cabbage and cauliflower in the Northeastern US.  Educational efforts are planned to reach the entire Northeastern US.  This is the first major outreach program targeting organic growers, and we anticipate that this project will launch several more projects that seek to reduce economic losses caused by SM to organic growers.  Ultimately, the viability of the organic Brassica industry in the Northeast US will be sustained.


    Project methods? 


    The 6 organic farm cooperators that currently have swede midge (SM) infestations in five counties in NY (Table 1).  Farms were selected based on their expressed interest in this project, geographic location and level of SM damage (minor to moderate/severe). 


     SM monitoring: Five SM pheromone traps will be deployed on each farm (Fig. 4 & 5), one trap/site; sites will be selected on a per farm basis to suit each farm’s uniqueness.  For example: spring emergence site (where Brassicas grew previous fall), in spring, summer and fall Brassica plantings, and site where Brassica transplants are produced.  It would also be possible to move a trap to another site after harvest allowing SM to be monitored on more than 5 sites/farm across the growing season.  Traps will be out from early-May to mid-October across the 5 sites/farm.  Traps will remain at each site for approximately 10-11 weeks.  The sticky liners and pheromone lures will be replaced every 2 and 4 weeks, respectively.   SM adults/trap will be counted and reported to the grower bi-weekly.  At crop maturity, the accompanying Brassicas will be scouted for SM infestation: damage will be rated (scale 0-3: 0 = none; 1 = damage noticeable to trained eye; 2 = puckering/scarring/malformation damage obvious, plants marketable; 3 = produce not marketable) and incidence of infested plants quantified.  When multiple plant-types or varieties per plant-type are grown in the same planting, each type will be assessed separately.




    Use of trap catch data: Trap catch and damage information will be used to help grower cooperators make real-time management decisions to the best of our current knowledge.  Calibrating trap catches with field damage levels will allow us to use trap catch data in the future as a tool to make informed management decisions.  For example, if 200+ SM/week resulted in 50% unmarketable broccoli plants, than we would know to not plant broccoli at a site where trap catches exceed 200 SM/week.  Overall, trap catch data will improve our understanding of 1) intensity and duration of spring emergence, 2) time span for SM to migrate into a new planting from a known infestation under differing topographies, 3) pace at which SM populations build or drop under different management practices, and 4) relative susceptibility of different plant types.  For example, capturing 100 SM/trap/week may result in severe, moderate and minor damage in Red Russian kale, broccoli and cabbage, respectively.




    On-farm trialing of exclusion netting:  Due to the very small-scale production of Brassicas on organic farms, elaborate randomized complete block designed trials with several replications may not always be feasible.  Having insect exclusion netting trialed in many on-farm scenarios will quickly give us insight into which circumstances this new technology will work to mitigate losses from SM.  One 14’ x 820’ role of insect exclusion (ProtekNet, 25 gram, Dubois Agrinovation) will be distributed among five cooperating farms so that each will have 100-150’.  Exclusion netting will be compared to an unprotected check, and on most farms, it will also be trialed in combination with mulch, which will reflect the most feasible option per farm.  Muddy Fingers Farm will compare both landscape fabric and hay mulch.  Each farm will set up at least one trial in a planting and a crop where they typically experience the most SM damage (Table 2).  When a trial is conducted in a spring crop, it would be feasible to set up another trial in a later planting with the same netting, if a grower is obliged.  Trials will have at least 20 plants per type per treatment-replicate and 3-5 replications.  Immediately after planting and mulching, exclusion netting will be applied to cover the entire width of bed (Fig. 2); excess netting will be secured so SM cannot sneak in.  A pheromone trap will be placed under the exclusion netting in one replicate of each exclusion netting-treatment, which will be compared to trap catches in an unprotected plot.  Traps will be serviced as per the monitoring project.  A sleeve will be installed at an opening so that traps may be serviced without risking entrance of SM into the exclusion netting.  We will not risk the marketability of the grower’s crops with our trials; if it becomes necessary to remove exclusion netting temporarily or permanently to ensure crop quality, then it will be removed and data will be collected under this real-world situation, as appropriate.


     Once the crop is ready to harvest, exclusion netting will be removed, SM damage rated as described above and incidence quantified.   Any other differences among treatments including plant size, maturity and other pest pressure (eg. Lepidopteron insects, flea beetles, weeds) will be quantified, if relevant. 


     Garlic oil repellant trials: Garlic oil repellant may be trialed in combination with exclusion netting trials, or separately, whichever is most suitable under the unique circumstances of each farm.  A stand-alone trial will consist of 3-5 replications of treated and untreated plots of 1-bed-wide by 10-20’-long and a minimum of 20 plants per type per treatment-replicate.  Hoepting will apply 1% solution of garlic essential oil (Bulk Apothecary) at 40 gpa using a CO2 backpack sprayer commencing within 1 week of transplanting and continuing biweekly until 2 weeks prior to harvest.  At harvest, SM damage will be rated and incidence quantified.  It would also be feasible to set up more than one trial in different plantings per farm. 




    Analysis: SM damage ratings and incidence collected from replicated trials will be analyzed using General Analysis of Variance and means will be separated using Fisher’s Protected LSD test with a significance of 5%.  Monitoring data will be summarized and related to the unique circumstances of each farm.




    Economic analysis: Only differences in inputs relating to SM management will be considered including cost of exclusion netting, garlic repellant, and labor requirements associated with treatments.  Yield data from the trials will be used, and growers will be asked to provide sale prices and input costs.


    Project timetable


    Meet with grower cooperators to devise their individual case studies and on-farm trials: where monitoring traps will be placed, how exclusion netting and garlic repellency trials will be set up (crop type, which planting, plot size, whether exclusion netting will be with or without mulch, type of mulch, etc.  Hoepting and grower cooperators.  April 2015. 2-3 days.


    Add organic management of swede midge section to website, “Swede midge information center for US”.  Hoepting and Chen. April 2015. 1 day.


    Write and submit “Be on the lookout for SM” article to NOFA newspaper, The Natural Farmer. Hoepting and Chen. April 2015. 1 day.


    Order field supplies (insect netting and associated supplies, pheromone traps and lures and associated supplies, etc.).  Technician. April 2015. 0.5 day.


    Prepare exclusion netting for growers (cut 820’ into 100-150’ sections, bend hoops, cut stakes, etc.). Technician.  April 2015. 1 day.


    Deploy first monitoring traps and drop off exclusion netting to growers. Technician. May 2015. 1 day.


    Set up exclusion netting trials.  Hoepting, technician and grower cooperators. May to August, 2015. 4 days.


    Monitor traps and scout for SM damage.  Technician, Hoepting.  May to October 2015, biweekly visits. 13 hours per week. 16 days.


    Spray garlic repellency trials.  Hoepting, technician.  May to October, 2015, as needed. 6 days.


    Harvest evaluations of trials. Technician, Hoepting. June to October, 2015, as needed. 7 days.


    Conduct four Twilight Meetings.  Hoepting, Technician, Grower cooperators.  August and September, 2015, half day each. 2 days.


    Collect grower feedback and economic info from growers.  Hoepting, technician, growers. November 2015. 2 days.


    Data entry, analysis and summary.  Technician, Hoepting.  May-December 2015. 5 days.


    Write and submit annual report.  Hoepting.  December 2015. 2 days.


    Present results at NOFA-NY winter conference.  Hoepting. January 2016. 1 day.


    Write and distribute project results in newsletter article, update SM website with latest information.  Hoepting, Chen. February 2016. 2 days.


    Present results at NOFA-VT winter conference. Chen. February 2016. 1 day.


    Write and submit final report to NESARE.  Hoepting. May 2016. 2 days.




    Dissemination of project results


     We will aim for our educational efforts to reach the majority of at-risk organic small-scale Brassica growers in Northeastern US where broccoli, cabbage and cauliflower are grown on 364 farms. 


    Hoepting and Chen will write an informational article designed to alert Brassica growers to be aware and on the lookout for swede midge.  The article will include details about diagnosing and scouting for SM as well as preventative management tactics.  This will be distributed in the Northeast Organic Farming Association (NOFA) newspaper, The Natural Farmer Summer 2015 issue, which should blanket Brassica growers in the Northeast US.  They will also develop a new section for the “Swede midge information site for the US” website (http://web.entomology.cornell.edu/shelton/swede-midge/), originally developed by Cornell University, to include organic management.  It will review all of the strategies that have been tested and failed in order to prevent blind implementation of failed methods and will be updated again in 2016 to reflect new information and recommendations derived from this project.


                    During the growing season, four of the grower cooperators including Canticle Farm, Quest Farm Produce, Muddy Fingers and Fellenz Family Farm will host twilight meetings where SM management will be demonstrated.  It is expected that at least 60 small-scale growers at risk for SM invasion will attend these meetings. 


    Updates and recommendations for managing SM generated from this project will be summarized in another article that will be distributed in The Natural Farmer in Spring 2016, as well as through the CCE Cornell Vegetable Program’s newsletter and website (http://cvp.cce.cornell.edu/) and other similar Extension newsletters/websites.  Hoepting and Chen will also present latest research results/recommendations at the NOFA-NY and -VT winter conferences, respectively, and will be available for one-on-one consultations with growers who require their expertise.  Growers hosting on-farm trials will serve as resources to other interested growers.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.