NEWA apple pollen tube growth model now available

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
Mary Concklin
Massachusetts University of Massachusetts
UMass Extension
Jon Clements
Michigan Michigan State University
Enviroweather Program
Beth Bishop
Minnesota Minnesota Apple Growers Association
JP Jacobson
New Hampshire University of New Hampshire
UNH Cooperative Extension
Cheryl Smith
New Jersey Rutgers University
Rutgers Cooperative Extension
Peter Oudemans
New York Cornell University | NEWA
New York State Integrated Pest Management Program
Dan Olmstead
North Carolina North Carolina State University
North Carolina Cooperative Extension
Mike Parker
Ohio The Ohio State University
Matt Wallhead
Pennsylvania Penn State University
Penn State Extension
Rob Crassweller
Vermont University of Vermont
UVM Extension
Terence Bradshaw
Virginia Virginia Tech
Virginia Cooperative Extension
Mizuho Nita
540-869-2560 x33
West Virginia West Virginia University
WVU Extension Service
M.M. Rahman
Wisconsin University of Wisconsin
UW Extension
Amaya Atucha
All other regions Cornell University | NEWA
New York State Integrated Pest Management Program
Dan Olmstead