Tree Fruit Newsletter — June 25, 2025
In this newsletter:
- SWD in cherry
- Preharvest intervals for cherry
- Fireblight spotted in Gala
- Summer tour agenda
Spotted Wing Drosophila (SWD) in Cherry
Cherries will become susceptible to SWD once about 20% of fruit begin to blush. Sweet cherries have reached this stage. Sour cherries are still green. Adult SWD flies will puncture the skin when they lay their eggs inside ripening fruit. This leads to brown rot and decay. SWD has not yet been found in IPM traps in Maine, according to David Handley, but has shown up in New York and Massachusetts.
Our earliest sweet cherry variety has started to turn light red, but has at least one week before it will be ready to harvest. Most varieties will be ready when they turn dark red and some are not at their best until almost black. At this time, it’s critical to know the preharvest intervals (PHI) for cherry.
These materials have the longest PHI for cherry:
Quash – 14 days
Topguard – 7 days
CAPTAN – 7 days
Most other fungicides are less than 2 days
Gladiator EC– 21 days
Diazinon – 21 days
Minector Pro – 21 days
ASANA – 14 days
Actara – 14 days
Endigo ZC – 14 days
Voliam Xpress – 14 days
Besiege – 14 days
Warrior II – 14 days
Mustang Max – 14 days
PHI for other materials can be found in the New England Tree Fruit Management Guide under summer sprays.
Danitol, Exirel, Magister SC and Malation have a relatively short PHI of 3 days and good efficacy for SWD. Admire Pro has a 0-day PHI and is listed as good for SWD. The PHI for Sevin XLR is 3 days, but it has only fair efficacy.
Herbicides can also have a long PHI on cherry.
Fireblight Infections
Several branches in our Gala block have become infected with fireblight. The photos below indicate what to look for when scouting your own orchards. The number of infections found this season is far fewer that last year. Check susceptible varieties first or any varieties that had late-blooming flowers.
Fireblight infections can be pruned out but wait for cool, dry weather to reduce the risk of further spreading it with your pruning tools. Avoid pruning when the foliage is wet. Prune shoots at least 12 inches back from visible infections or into older branch sections, if possible.
Maine Pomological Society Summer Tour at Cooper Farms in Monmouth
155 Norris Hill Road, Monmouth ME 04259
July 9, 2025
9:30 a.m. — 2:30 p.m.
The Maine State Pomological Society and Cooper family cordially invite you to attend this year’s Summer Tour to be held at Cooper Farms at their Monmouth facility. To RSVP, call Renae Moran at (207) 713-7083 (or email at rmoran@maine.edu) by July 1. Preregistration is not required, but is certainly appreciated. Cost to attend the Summer Tour is $30. Admission for two grower-members or one associate member is included with annual dues. To pay dues, please contact Margie Hansel, the Society secretary (mhansel@maine.rr.com).
One credit pesticide applicator recertification pending BPC approval.
Agenda
9:30 a.m. — Welcome and Registration
10:00 a.m. — Tour of the packing house with Karen Killian and Cooper Farms staff.
10:45 a.m. — Hillary Peterson, Maine Department of Agriculture, Conservation and Forestry, the IPM Council of Maine.
Supporting Fruit Growers through IPM: Updates, Resources, and Opportunities. Hillary Peterson, Integrated Pest Management Specialist with the Maine Department of Agriculture, Conservation and Forestry, will provide an overview of the Maine IPM Council and its work on behalf of farmers across the state. She will also highlight current IPM resources and priorities relevant to the tree fruit industry, with room for discussion about emerging needs and opportunities for grower involvement. Hillary completed her Ph.D. at Penn State University, where her research focused on biological control of brown marmorated stink bug in apple, peach, and cherry orchards.
11:15 a.m. — Advertising topic, to be determined
11:45 a.m. — Pomological Society reports from standing committees
Noon to 1:00 — Lunch
1:00 p.m. — Orchard Tour
The Monmouth orchard features Gala, Honeycrisp and its high-coloring strains, high density orchards, dwarfing rootstocks, and great views of the surrounding area.
- The Eco Apple program in action. Their website: For Growers – Red Tomato
- Glen Koehler, UMaine Extension, Apple IPM updates and what to look out for in late summer.
Directions to Cooper Farms — 155 Norris Hill Road, Monmouth, ME 04259
From the north and east:
I95 Exit 109b, go West on Rte. 202 (toward Winthrop) for 16 miles. Turn left on Norris Hill Road. Cooper Farms is on the left, a short distance past the Highmoor Farm orchards. Alternate routes exist.
From the south and west:
I95 exit 86, left on Rte. 9 and continue 0.7 miles, then take a right onto Pleasant Hill Road for 0.8 miles. Continue through the stoplight where the road becomes Rte. 132 (Wales Rd. and then Pond Rd.) for 4.6 miles. Take left onto Leeds Junction Road, travel 2.9 miles to Rte. 202. Take a right onto Rte. 202 and go 1.5 miles to the Norris Hill Road, and take a right. Cooper Farms is on the left, a short distance past the Highmoor Farm orchards.
Renae Moran
University of Maine Cooperative Extension: Tree Fruits
PO Box 179
Monmouth, ME 04259
(207) 933-2100
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