Southeastern apple growers observed low temperatures near or below critical temperatures for apple three times in a two-week period. These potential frost/freeze events coincided with the bloom period for most varieties (see table below).
WNC Apple Flower Bud Mortality Assessments
In cooperation with MaryMorgan Arrington (Wilkes County Horticulture Agent) and Terry Kelley (Henderson County Extension Director and Tree Fruit Agent), we evaluated apple bud survival across four sites in Western North Carolina.Sites were in close proximity to NEWA weather stations. This evaluation was conducted following the potential freeze event on April 8th, 2018.
The presence and severity of frost/freeze damage was evaluated using a method for assessing fruit bud survival. At each site, ~10 representative limbs from four varieties (Pink Lady, Gala, Golden Delicious, and Rome) were collected and viability of all blossoms was assessed. Click on each table to enlarge.
Extent of bud mortality ranged widely across varieties and sites. Additionally, potentially injurious air temperatures were observed at some sites after this assessment was conducted. Several factors determine the potential severity of blossom mortality, including: site, location, bud development stage at time of freeze event, lowest temperature observed, the duration of low temperature exposure, cultivar, cropping history, and tree health.
This assessment would not be possible without the hard work of several individuals, including: MaryMorgan Arrington, Tracy Cavagnaro, Chris Clavet, Bill Gardo, Terry Kelly, Kevin Landis, Gary Madere, and Ken Olson. Appreciation is extended to MaryMorgan and Terry, who collected samples from the sites presented. Thank you for your great help!