5 May 2026 - Recent Weather Impacts on Pomes & Stones with Win Cowgill, Scab and Fire Blight Updates

Win Cowgill is an emeritus Rutgers Professor who currently owns his own consulting company called Win Enterprises where he consults on horticulture and pomology. And consults from New Jersey up to Maine. Kerik continues to talk about getting through extended/multiple apple scab infection periods, and the lack of fire blight risk in a cold bloom.

This week on Scaffolds, I talk to Win Cowgill an emeritus Rutgers professor about what is going on in the north east region with all of the freezes and some options for what to do if you have damage in both apple and peach, Kerik gives us an update on scab and fire blight management strategy, and Anna closes the episode with the state of the state update on phenology, degree days, and trap captures around the state.

LInk from Win Cowgill

MSU Critical Spring Temperatures for Tree Fruit Bud Development Stages https://www.canr.msu.edu/fruit/uploads/files/TreeFruitCriticalTemperatures.pdf

Historical Phenology and Average Degree Day Accumulation Base 43 (for reference)

- Tight cluster (McIntosh) || 228 ± 27 || 27-Apr ± 7 days

- Pink (McIntosh) || 289 ± 26 || 3-May ± 7 days

- Full bloom (McIntosh) || 378 ± 35 || 10-May ± 6 days

- Petal fall (McIntosh) || 479 ± 42 || 18-May ± 6 days

Phenology & DDs for NY NEWA Stations from 1/1 – 5/4

Station || Stage || DD 43F || DD 43 Forecast Through 5/10 ||

Geneva (AgriTech North) || Early Bloom || 460 || 476

Highland (HVRL) || Petal Fall || 524 || 616

Clifton Park || Bloom || 421 || 494

Peru (Forrence) || Open Cluster || 284 || 346

Medina (Roberts) - Inland || Early Bloom || 420 || 464

Appleton North - Lake || Early Bloom || 310 || 346

Fairville (The Apple Shed) - Inland || Early Bloom || 447 || 491

Williamson (DeMarree) - Lake || Early Bloom || 375 || 404

*all DDs Baskerville-Emin, B.E

Upcoming Pest Events

Pest/Phenology Event || DD Base 43˚F || Approx. Date

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Tight cluster (McIntosh) || 228 ± 27 || 105 ± 19 || 27-Apr ± 7 days

Tarnished plant bug – 1st observed || 222 ± 105 || 105 ± 62 || 25-Apr ± 15 days

OBLR – 1st overwintered larvae observed || 236 ± 78 || 112 ± 48 || 29-Apr ± 7 days

Black stem borer – 1st adult catch || 283 ± 50 || 137 ± 40 || 6-May ± 3 days

European red mite – egg hatch observed || 284 ± 53 || 134 ± 34 || 6-May ± 4 days

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Pink (McIntosh) || 289 ± 26 || 139 ± 21 || 3-May ± 7 days

OFM Traps set out || Pink

Oriental fruit moth – 1st adult catch || 229* ± 44* || 126 ± 33 || 2-May ± 8 days

RBLR – 1st flight peak || 303 ± 75 || 150 ± 48 || 4-May ± 9 days

STLM – 1st flight peak || 337 ± 71 || 168 ± 45 || 7-May ± 8 days

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Full bloom (McIntosh) || 378 ± 35 || 192 ± 25 || 10-May ± 6 days

OBLR Overwintered Gen. Sample || Bloom

Codling Moth Traps set out || Bloom

Cold Temperature and Frost Risk

Picture Table of Critical Spring Temperatures for Tree Fruit Bud Development Stages https://www.canr.msu.edu/resources/picture-table-critical-spring-temperatures-for-tree-fruit-bud-development-stages

Regional Weather Events page for NEWA weather stations, including a map of freeze events from 2024 and 2025. https://newa.cornell.edu/regional-weather-events/

Cornell Statewide Frost Protection webinar held on Friday April 12th recording now available online here: https://youtu.be/TIBEpfb98ws

Scouting and Monitoring Resources

NY Tree Fruit Pest Monitoring Network Blog

https://blogs.cornell.edu/treefruitpests/

Interested in collaborating and contributing trap capture data? Contact Anna Wallis aew232@cornell.edu

Quick Guide for Apple Insect Pests https://help.nysipm.org/hc/en-us/articles/23290226665751-NEWA-Quick-Guide-for-Apple-Insect-Pests

Virtual Orchard Scout Training webinar recording on the Cornell IPM YouTube channel

https://www.youtube.com/watch?v=OtyOWCL1Q2A