A new model that helps apple growers precisely time thinning sprays during bloom is available in time for the 2019 growing season on the NEWA website. It is called the pollen tube growth model (PTGM).
Developed by Greg Peck, Assistant Professor of Horticulture at Cornell University, PTGM expands available apple management options for apple producers, helping those who use bloom thinning to increase the chances of ideal crop load at harvest.
Peck collaborated with researchers at Virginia Tech to adapt their existing PTGM model for use on the NEWA platform, linking real-time hourly weather data with pollen tube growth rates collected under controlled temperature conditions.
Apple varieties in the pollen tube growth model include Fuji, Gala, Golden Delicious, Granny Smith, Honeycrisp, Red Delicious, and Pink Lady.
An article by Peck and Olmstead was published in the Spring 2019 issue of Fruit Quarterly that provides instruction and technical information about the PTGM. It also describes the research, justification, and logic for model development. Click the link below to view a PDF version of the article.
Implementing the Pollen Tube Growth Model on NEWA
If you are a New York producer and have additional questions about the PTGM, reach out to your regional extension specialist to learn more about this model.
Table 2. NY apple extension specialists.
| Affiliation | Name |
| New York State IPM Program | Julie Carroll |
| Cornell Cooperative Extension Lake Ontario Fruit Team | Craig Kahlke |
| Mario Sazo | |
| Cornell Cooperative Extension Eastern New York Horticulture Team | Mike Basedow (northern NY) |
| Dan Donahue (Hudson Valley) |
Outside of NY, get in touch with your NEWA state coordinator to ask about local extension resources, expertise, and applicability of the PTGM in your area.
Table 3. NEWA state coordinators.
| Region | Entity | State coordinator |
| Connecticut | University of Connecticut UConn Extension http://www.extension.uconn.edu/ |
Mary Concklin 860-486-6449 mary.concklin@uconn.edu |
| Massachusetts | University of Massachusetts UMass Extension ag.umass.edu |
Jon Clements 413-478-7219 clements@umext.umass.edu |
| Michigan | Michigan State University Enviroweather Program http://www.enviroweather.msu.edu/ |
Beth Bishop 517-432-6520 bishopb@msu.edu |
| Minnesota | Minnesota Apple Growers Association http://www.minnesotaapple.org/ |
JP Jacobson 651-429-6577 jpmnapples@gmail.com |
| New Hampshire | University of New Hampshire UNH Cooperative Extension extension.unh.edu |
Cheryl Smith 603-862-3841 cheryl.smith@unh.edu |
| New Jersey | Rutgers University Rutgers Cooperative Extension njaes.rutgers.edu/extension |
Peter Oudemans 609-726-1590 oudemans@aesop.rutgers.edu |
| New York | Cornell University | NEWA New York State Integrated Pest Management Program newa.cornell.edu |
Dan Olmstead 315-787-2207 support@newa.zendesk.com |
| North Carolina | North Carolina State University North Carolina Cooperative Extension www.ces.ncsu.edu |
Mike Parker 919-515-1198 mlp@ncsu.edu |
| Ohio | The Ohio State University USDA/OARDC oardc.osu.edu |
Matt Wallhead 440-320-0705 wallhead.3@osu.edu |
| Pennsylvania | Penn State University Penn State Extension extension.psu.edu |
Rob Crassweller 814-863-6163 rmc7@psu.edu |
| Vermont | University of Vermont UVM Extension www.uvm.edu/extension |
Terence Bradshaw 802-922-2591 tbradsha@uvm.edu |
| Virginia | Virginia Tech Virginia Cooperative Extension ext.vt.edu |
Mizuho Nita 540-869-2560 x33 nita24@vt.edu |
| West Virginia | West Virginia University WVU Extension Service https://extension.wvu.edu/ |
M.M. Rahman 304-293-8838 MM.Rahman@mail.wvu.edu |
| Wisconsin | University of Wisconsin UW Extension www.uwex.edu |
Amaya Atucha 608-262-6452 atucha@wisc.edu |
| All other regions | Cornell University | NEWA New York State Integrated Pest Management Program |
Dan Olmstead 315-787-2207 support@newa.zendesk.com |