Preventing crop losses to Swede Midge on small-scale organic farms Cornell Cooperative Extension Vegetable Program Great Lakes vegetable Working Group, London, Ontario: March 4, 2016

Small-scale organic brassica growers at risk for swede midge Due to small size and high proportion of acreage cropped to brassica crops in multiple plantings Long and wide crop rotations ineffective Swede midge damage is easily misdiagnosed Economic losses occur before growers diagnose SM

Place traps 1 foot above ground within crop canopy Replace lures every 4 weeks Replace sticky liners 1-3x per week Monitoring swede midge with pheromone traps

Spring Emergence Case studies, 2015 Mid-May until mid-July

Spring Emergence

Spring Emergence & Brassica Plantings April ‘15 cabbage planting Spring emergence trap # Cauliflower Peak trap catch June 5: 38/day Spring emergence trap # Brussels Sprouts Peak trap catch May 27: 81/day Field 4 = 9.9 acres

Spring Planting in Field Where Spring Emergence Occurs cabbage

Swede Midge Damage Rating Scale 0 = no damage; healthy 1 = minor damage; plant unaffected and marketable 2 = moderate damage; plant quality and/or yield reduced, but marketable 3 = major damage; remnants of a growing point, but not marketable 4 = severe; blind head Fig. 10. Five-point swede midge damage rating scale (0-4); developed by Hoepting.

When Brassicas were planted while SM was emerging from the spring emergence site, crop injury resulted. Spring Planting in Field Where Spring Emergence Occurs Damage rating (out of 4.0) on July 8: Red Cabbage: 2.8 (major)

Spring Emergence

Spring Emergence & Brassica Plantings Field 1 = 4.4 acres Spring emergence trap # Cauliflower Peak trap catch May 27: 93/day Spring emergence trap # Collard greens Peak trap catch May 27: 66/day July 2015 cabbage planting Spring emergence trap # Kale Peak trap catch June 17: 77/day

When Brassicas were planted after SM spring emergence was complete, crop injury was minor. Spring Emergence Complete Planting After Spring Emergence Complete Damage ratings (out of 3.0) on Sep 15: Red Cabbage: 0.6 (minor)

Crash population by not growing fall Brassica crops Crash population by not growing spring Brassica crops Insect exclusion netting More research required: Would an infested summer crop serve as a spring emergence site the following year? Host preference and/or susceptibility may be an important management strategy Not enough land base for wide crop rotations?

Crop-Type Differences

Damage Assessment Scale 0-4: Oct 8 (broccoli) & 15 (BS), 2015 Crop % SM infested % Unmarketable due to SM Average Swede Midge Damage Rating Broccoli91.7%58.3%2.7 (Major) Brussels sprouts 58.3%O%0.6 (Very Minor) Damage Assessment – July 8, 2015 Variety% SM infested % Unmarketable due to SM Average Swede Midge Damage Rating Red Cabbage (Severe) Green Cabbage (Moderate) Cone Cabbage (minor/moderate)

Crop-Type Differences Generally, Broccoli, Red Russian kale and kohlrabi appear to be the most susceptible and/or attractive to swede midge Asian brassicas appear to be least preferred or less tolerant Red cabbage more susceptible than green cabbage Asian Brassicas Red Russian Kale Broccoli

Start with Clean Transplants Rogue out infested transplants Do not plant blind heads Start with Clean Transplants Swede Midge-Infested Transplant Seedling

Plant in open windy areas vs. sheltered Disrupt mating and host selection Delay/reduce population buildup Avoid planting downwind of a known emergence site Does mulch disrupt emergence? Or pupation? Garlic oil as a repellent? Initial laboratory studies suggest it does (if brassica smells like garlic, will swede midge seek it out?) Preliminary field trials in 2015 failed: washed off? 2016 field trials will include spreader-sticker Hedgerows/tree lines can serve as barriers that can delay swede midge distribution Other Best Management Practices

Insect Exclusion Netting ProtekNet 14’, 25 gram, Dubois Agrinovation (4 ft x 4 ft hoops) Demonstrated success in Quebec, Canada Growers hesitant to trial due to high costs (~$400 per 100 ft of protections

Insect Exclusion Netting

High Risk Site: on ground that had SM infestation in broccoli in fall 2014 Treatment % SM % unmarketa ble (rating 3 & 4) Average SM damage rating 1 of infested plants % unmarketabl e due to heat stress Comments Bare ground (major) 0 Multiple shoots & branching low to the ground Bare ground + Insect Exclusion Netting (major) 0 Straw Mulch + Insect Exclusion Netting (major) 0ICW BioTello biodegradable plastic mulch + Insect Exclusion Netting (major) 9.5 Insect Exclusion Netting ± Mulch Spring Broccoli

Low Risk Site: on ground not cropped to Brassicas in 2014, same field as high risk site Treatment % SM % unmarketable (rating 3 & 4) Average SM damage rating 1 of infested plants % unmarketabl e due to heat stress Comments Bare ground Multiple shoots & branching low to the ground Bare ground + Insect Exclusion Netting 0000 Delayed maturity compared to plastic mulch Straw Mulch + Insect Exclusion Netting 00017ICW BioTello biodegradable plastic mulch + Insect Exclusion Netting Insect Exclusion Netting ± Mulch Spring Broccoli

Assume that you have swede midge or will get it Be able to recognize it when you have it Crashing population or not allowing population to build is key to long-term management Far and wide crop rotation is the most effective Effective management will look different on each farm Summary

More Information Note: Organic section will be added/updated this winter including results from this project. Where to order pheromone traps How to identify swede midge on sticky cards Scouting for swede midge and lot’s of pictures of damage

Funding: NESARE Partnership grant Cornell Toward Sustainability Foundation Grower Cooperators: Mark Printz, Canticle Farm, Allegany, NY (Cattauraugus) Denny & Bridgett Reynolds, Quest Farm Produce, Almond, NY (Allegany) Sasha Khodorkovskiy, Living Acres Farm, Alfred Station, NY (Allegany) Andy & Eric Fellenz, Fellenz Family Farm, Phelps, NY (Ontario) Robin Ostfeld, Lou JohnsBlue Heron Farm, Lodi, NY (Seneca) Liz Martin & Matthew Glen, Muddy Fingers Farm, hector, NY (Schuyler) Acknowledgements