14 April 2026 - Reminders for Early Season, Higher Risk for Apple Scab

This week on Scaffolds, I give some reminders to think about as the season starts, Kerik talks scab predictions, and Anna gives us our weekly state of the state update on degree day accumulations around the state. Kerik:  Apple Scab Disease forecast predictions for New York as of 4-12-26: There’s a lot of variability for Apple Scab risk across the regions. Eastern NY and the capital district have an easy week with few wetting periods and low levels of ejection. The lake champlain region may not all be at green tip. Western NY and the fingerlakes have accelerated apple scab maturity and prolonged wetting periods that span the week with high risk. In this region, the average temperatures during wetting periods are low 60s and could lead to many infections. State of the StateHistorical 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 – 4/13Station || Stage || DD 43F || DD 43 Forecast Through 4/19 ||Geneva || 1/2" green || 249 || 364Highland (HVRL) || tight cluster || 257 || 404Clifton Park || green tip || 178 || 301Peru (Forrence) || first green || 114 || 193Medina (Roberts) - Inland || 1/2" green || 214 || 306Appleton North - Lake || 1/2" green || 148 || 207Fairville (The Apple Shed) - Inland || 1/2" green || 235 || 334Williamson (DeMarree) - Lake || 1/2" green || 180 || 254*all DDs Baskerville-Emin, B.E Upcoming Pest EventsPest/Phenology Event || DD Base 43˚F || Approx. DateSTLM Traps set out   || 1-AprPear psylla – egg laying || 84 ± 44 || 33 ± 21 || 4-Apr ± 11 daysRBLR – 1st catch || 144 ± 32 || 60 ± 20 || 17-Apr ± 9 daysRosy apple aphid – 1st nymphs present || 189 ± 55 || 86 ± 30 || 25-Apr ± 7 daysSTLM – 1st adult catch || 168 ± 48 || 73 ± 28 || 20-Apr ± 9 daysSTLM – 1st egg observed || 208 ± 65 || 94 ± 36 || 27-Apr ± 5 days---Tight cluster (McIntosh) || 228 ± 27 || 105 ± 19 || 27-Apr ± 7 daysTarnished plant bug – 1st observed || 222 ± 105 || 105 ± 62 || 25-Apr ± 15 daysOBLR – 1st overwintered larvae observed || 236 ± 78 || 112 ± 48 || 29-Apr ± 7 daysBlack stem borer – 1st adult catch || 283 ± 50 || 137 ± 40 || 6-May ± 3 daysEuropean red mite – egg hatch observed || 284 ± 53 || 134 ± 34 || 6-May ± 4 days---Pink (McIntosh) || 289 ± 26 || 139 ± 21 || 3-May ± 7 daysOFM Traps set out || PinkOriental fruit moth – 1st adult catch || 229* ± 44* || 126 ± 33 || 2-May ± 8 daysRBLR – 1st flight peak || 303 ± 75 || 150 ± 48 || 4-May ± 9 daysSTLM – 1st flight peak || 337 ± 71 || 168 ± 45 || 7-May ± 8 days---Full bloom (McIntosh) || 378 ± 35 || 192 ± 25 || 10-May ± 6 daysOBLR Overwintered Gen. Sample || BloomCodling Moth Traps set out || BloomCold Temperature and Frost RiskPicture 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 on 4/25 and 26. 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/TIBEpfb98wsScouting and Monitoring ResourcesVideo: Apple Insect Targets and IPM Practices (including explanations of Degree Day calculations),  https://youtu.be/NwyBAcvbpUs  NY Tree Fruit Pest Monitoring Network Bloghttps://blogs.cornell.edu/treefruitpests/Interested in collaborating and contributing trap capture data? Contact Anna Wallis [email protected] Guide for Apple Insect Pests https://help.nysipm.org/hc/en-us/articles/23290226665751-NEWA-Quick-Guide-for-Apple-Insect-Pests