Tree Fruit Newsletter — January 17, 2025
In this newsletter:
- Pruning Out Fireblight in Dormant Trees
- New Apple Variety Evaluations
- Soil Temperatures at Highmoor Farm
- Upcoming Meetings and Webinars
Fireblight in Dormant Trees
Adapted from Apple and Pear Disease – Fire Blight, Dormant Removal of Cankers, Kari Peter
Last year, fire blight was found in several orchards around the southern half of the state because weather conditions favored the disease to a greater extent than in years past. This means that there are some overwintering cankers that should be removed during pruning, if possible. Fireblight bacteria overwinter in living tissue surrounding cankers that formed at the base of spurs or shoots killed the previous season. Cankers may have also formed where cuts were previously made when infected shoots were removed.
Canker removal during dormant pruning will help reduce fireblight infections in the coming season. Trees with trunk or rootstock cankers should be removed completely if you don’t want it to continue spreading fireblight.
What do cankers look like?
-
- Localized roughened or cracked bark, especially around wounds, branch stubs, old pruning cuts.
- Bark that is darker than the surrounding healthy bark tissue.
- Roughened or darkened areas appearing wrinkled or sunken.
When you see a canker, prune 6 – 12 inches from the canker’s visible edge preferably into 2-year-old wood or older since older wood is more resistant to the bacteria. This will be easier in larger trees and more challenging in smaller dwarf trees. Since the bacteria are dormant during the winter, disinfecting pruning tools is not necessary.
Additional info on pruning out fireblight any time of year: When to prune out fire blight: To prune or not to prune – MSU Extension
Initial observations of Some New Apple Varieties
The apple variety trial at Highmoor Farm began producing fruit this last year, so we had a chance to do some initial observations and taste tests.
Ambrosia – fruit size is too small for general marketing. Thick skin with some russetting. Very dense flesh. Flavor is good. Holds up ok in storage into January but with some mealiness. Not disease resistant.
Evercrisp – Medium fruit size. Flavor is sweet and somewhat bland, but texture is good. Holds up good in storage to at least Jan. Good color and general appearance. Harvest was in mid to late October.
Triumph – Medium fruit size. Good texture and flavor, more sweet than sour. Good storage until mid November. Some internal browning after that. This will limit its large-scale production. Less biennial than its Honeycrisp parent. No signs of bitter pit, either. Resistant to apple scab. Harvest was late Sept. into early Oct.
Rosalie – Small to medium fruit size. Less red color than other varieties. It is holding up ok in storage, but flavor loss has occurred in some apples. Flavor is on the tart side. Flavor and texture at harvest were great. We did not use Smartfresh for any of our varieties. Harvest was mid October.
Soil Temperatures at Highmoor Farm
With no snow cover and cold temperatures expected, I am concerned about soil temperatures dropping below the cold tolerance of apple and peach roots. As long as there is good snow cover, the soil temperature remains near 32 °F, so roots never experience cold temperature injury. Some dead plant debris also helps to insulate the soil.
We are currently measuring a temperature of 32 °F in the strawberries under straw and at a soil depth of 8” without straw. It will take several days of very cold air temperatures to get soil temperature to reach 23 °F, the temperature that kills roots in the more tender Malling rootstocks (M.7 and M.9) and even longer for the soil temperature to reach 12 °F, the level of hardiness in M.26, Bud.9, G.30, G.935 and G.41. Geneva apple roots have greater cold tolerance than M.9, but few of them have not yet been through a “test” winter like the one we had in 2004. Hardiness in peach and cherry roots is unknown.
We will continue to monitor the soil temperature at Highmoor Farm in the strawberries and other locations.
Northeast Extension Fruit Consortium
This winter, we will be hosting the webinar series in New England and eastern New York. Topics include marketing, weed management, apple scab, bitter rot, and new research on cold hardiness in apple rootstocks and peach varieties. Some of the sessions will offer pesticide applicator recertification credits. For more information and to register, visit the Northeast Extension Fruit Consortium webpage.
Sessions will be held (see specific dates below) from noon to 1:30 p.m. Pesticide credit(s) will be available for indicated sessions. Pre-registration is required.
- February 12, 2025 — Brian Moyer, Penn State Extension will discuss “10 Common Marketing Mistakes”. No recertification credits offered.
- February 19, 2025 — Dr. Maria Gannett, UMass Extension Fruit and Vege Weed Specialist will discuss “Basic Orchard Weed ID and Management”. Pesticide credits pending.
- February 26, 2025 — Dr. Anna Wallis, Senior Extension Associate, NYS Integrated Pest Management and Dr. Kerik Cox, Associate Professor, School of Integrative Plant Science, Plant Pathology and Plant-Microbe Biology Section, Cornell AgriTech will dig into “Why Did My Scab Program Fail in 2024?”. Pesticide credits pending.
- March 5, 2025 — Dr. Srdjan Acimovic Assistant Professor, Tree Fruit and Specialty Crop Pathologist at Virginia Tech University. This presentation will cover the biology and environmental conditions that favor bitter rot on apples; the cultural, fungicidal, and other management options to reduce losses; and new areas of research to understand and minimize this important apple disease.
- March 12, 2025 — Dr. Jason Londo, Associate Professor, School of Integrative Plant Science, Horticulture Section, Cornell AgriTech “Understanding Cold Hardiness Risks in Fruit Crops”, and Renae Moran, University of Maine “Update on Cold Hardiness in the New Peach Variety Trial”.
Cornell Fruit Winter Webinar Schedule
Please save the date for six upcoming bi-weekly lunch hour webinars happening on Fridays this January through March. Webinars hosted by CCE ENYCHP, NYSIPM, CCE Harvest NY, and CCE LOFP.
Week 1: Digging in to Pruning and Soil Health
Speakers: Mario Miranda Sazo (CCE LOFP) and Dr. Debbie Aller (Cornell CALS)
Friday January 17, 2025 11:00am-12:30pm
Week 2: Cider Apples – Mechanized Harvesting and Patulin Food Safety
Speakers: Dr. Greg Peck (Cornell CALS) and Dr. Randy Worobo (Cornell CALS)
Friday January 31, 2025 11:00am-12:30pm
Speakers: Liz Higgins (CCE ENYCHP), Josh Morgenthau (Fish Kill Farms), Jim Bittner (Bittner-Singer Orchard, and Kevin Clark (Rose Hill Farm)
Friday February 14, 2025 11:00am-12:30pm
Week 4: Biopesticides and Controlled Environment Agriculture (CEA) for Berries
Speaker(s): McKenzie Schessl (Cornell AgriTech) and Samantha Willden (Cornell AgriTech)
Friday February 28, 2025 11:00am-12:30pm
Week 5: St. Peachtrick’s Day: Stone Fruit Insect and Disease Management
Speakers: Dr. George Sundin (Michigan State University) and Brett Blaauw (University of Georgia)
Friday March 14, 2025 11:00am-12:30pm
After registering, you will receive a confirmation email containing information about joining the meeting.
March Tree Fruit Preseason Meeting
Tuesday, March 19, 2025
8:00 a.m. — 4:00 p.m.
Room 170, University of Southern Maine / Lewiston Auburn College, 51 Westminster Street, Lewiston ME
Preregistration is NOT required. The $30 registration fee is due at the door, but is waived for two people per member farm of the Maine State Pomological Society if dues are paid prior to the meeting. Membership dues will be accepted at the meeting but will not qualify for the registration fee waiver.
Attendance qualifies for 3 pesticide applicator recertification credits.
For the more information and the tentative agenda, visit the Preseason Tree Fruit Meeting page.
Renae Moran
University of Maine Cooperative Extension: Tree Fruits
PO Box 179
Monmouth, ME 04259
(207) 933-2100
Mention of a trademark, proprietary product, or vendor does not constitute a guarantee or warranty of the product, nor does it imply approval or disapproval to the exclusion of other products or vendors that may also be suitable.
In complying with the letter and spirit of applicable laws and pursuing its own goals of diversity, the University of Maine System does not discriminate on the grounds of race, color, religion, sex, sexual orientation, transgender status, gender, gender identity or expression, ethnicity, national origin, citizenship status, familial status, ancestry, age, disability physical or mental, genetic information, or veterans or military status in employment, education, and all other programs and activities. The University provides reasonable accommodations to qualified individuals with disabilities upon request. The following person has been designated to handle inquiries regarding non-discrimination policies: Director of Equal Opportunity, 5713 Chadbourne Hall, Room 412, University of Maine, Orono, ME 04469-5754, 207.581.1226, TTY 711 (Maine Relay System).