21 April 2026 - Talking Freeze Events with Dr. Jason Londo, Scab Updates and Fire Blight Beginnings

This week on scaffolds, I talk to Dr. Jason Londo about the freeze event we just had, Kerik talks scab risk and the first fire blight insight of the season, and anna gives us the state of the state update on degree day accumulations and phenology progress across the state.

State of the State Show Notes

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 – 4/20

Station || Stage || DD 43F || DD 43 Forecast Through 4/26 ||

Geneva (AgriTech North) || Pink || 349 || 392

Highland (HVRL) || King Bloom || 394 || 438

Clifton Park || Pink || 299 || 334

Peru (Forrence) || 1/2" Green || 175 || 199

Medina (Roberts) - Inland || Tight Cluster || 313 || 352

Appleton North - Lake || Tight Cluster || 220 || 241

Fairville (The Apple Shed) - Inland || Tight Cluster || 330 || 364

Williamson (DeMarree) - Lake || Tight Cluster || 281 || 295

*all DDs Baskerville-Emin, B.E

Upcoming Pest Events

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

STLM Traps set out || 1-Apr

Pear psylla – egg laying || 84 ± 44 || 33 ± 21 || 4-Apr ± 11 days

RBLR – 1st catch || 144 ± 32 || 60 ± 20 || 17-Apr ± 9 days

Rosy apple aphid – 1st nymphs present || 189 ± 55 || 86 ± 30 || 25-Apr ± 7 days

STLM – 1st adult catch || 168 ± 48 || 73 ± 28 || 20-Apr ± 9 days

STLM – 1st egg observed || 208 ± 65 || 94 ± 36 || 27-Apr ± 5 days

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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

Video: Apple Insect Targets and IPM Practices (including explanations of Degree Day calculations), https://youtu.be/NwyBAcvbpUs

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

Apple IPM Intensive Workshop playlist https://www.youtube.com/playlist?list=PLoNb8lODb49vifrm9Tla4GmAVhlIL0527

Northeast Regional Climate Change Monthly Maps

https://www.nrcc.cornell.edu/regional/monthly/monthly.html