Northwest Michigan fruit update – April 30, 2024
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EmailMost orchards came through the cold weather last week, but there are pockets of isolated damage where temperatures dipped into the mid- to low 20s. Sweet cherries are in bloom. Tart cherries are just showing white. Apples are at early pink.
Weather report
The cold, overnight temperatures of last week were concerning, especially since some forecasts were predicting nighttime temperatures to hit the mid-20s. These cold weather conditions came in both cold and windy and cold and calm. On April 23, the low temperature at the Northwest Michigan Horticulture Research Center was 34.9 degrees Fahrenheit. Temperatures dropped lower the following night, April 24, to 30 F. On April 25, the Enviroweather station at the Northwest Michigan Horticulture Research Center recorded an overnight low of 28.8 F. Even though the forecast predicted warmer overnights last Friday, April 26, we still recorded a low of 33.1 F at the station.
The overnight lows at the station were higher than other Enviroweather stations across northwest Michigan. During the overnight of April 24-25, there were many cold temperatures around the region, particularly during the hour from 6–7 a.m.: 25 F in Williamsburg, 25.9 F in Elk Rapids and 28.9 F in Eastport. During that same night from 3-4 a.m., the Benzonia station recorded 26.3 F and Onekama/Bear Lake recorded 22.6 F.
We have accumulated 285.7 growing degree days (GDD) base 42 and 106.5 base 50 so far this season. These accumulations are still well ahead of our long-term average: 198.7 GDD base 50 and 82.2 GDD base 42. We received 0.42 inches of rainfall on April 28 and another 0.78 inches on April 29.
According to Jeff Andresen, the weather this week will bring some rain. There is some rain in the forecast for tomorrow, May 1, but the highest chance of some rainfall is in the northern part of the state; much of the rest of Michigan will be dry tomorrow. Thursday is also supposed to be dry, but rain will move into the state Thursday night and Friday morning. The rain that is in the forecast is predicted to be light with low accumulation.
Today will be the coolest day of the week, particularly in northern Michigan where the daytime high will not likely rise above the 50s. Temperatures will warm over the week, and the forecast is predicting mid- to high 60s for Traverse City. We may see the temperatures top out into the low 70s by next Monday, May 6. Conditions for the medium range forecast are predicted to be warmer than normal.
Crop report
The following growth stages were evaluated at the Northwest Michigan Horticulture Research Center yesterday afternoon (April 29):
- Balaton – early white bud
- Bartlett Pear – white bud
- Montmorency – early white bud/white bud
- Potomac Pear – white bud
- Emperor Francis – 90% bloom
- Gold – 20% bloom
- Ulster – 95% bloom
- Riesling – early bud swell
- Gala – pink
- Honeycrisp – early pink
There is still pruning going on in the orchards as growers try to wrap up this task for the season. Growers are also busy planting, and some growers are waiting for fields to dry out before they can move into the orchards with their tractors. Honey bee hives are more common in orchards this week as growers prepare for bloom. As sweets are somewhere between 20-95% bloom at the station, most bees are in sweet blocks. Growers are also busy with cover sprays after the rain this past week and with rain in the forecast for later this week. Winds have also been a challenge for spray applications.
Pest report
Honey bees will forage at temperatures at 65 F or warmer. Bumble bees and solitary bees will forage at temperatures 5-10 degrees cooler than honey bees. During bloom, growers are encouraged to implement practices that minimize pesticide exposure to bees by using reduced risk pesticides and spraying at times when pollinators are not active. Find tips and guidelines to minimize bee pesticide exposure.
Apple scab
Apples should be recovered after the rain this past weekend to protect against primary scab infection. Leaf tissue will continue to expand and need to be covered before the next rain.
RIMpro links:
Brown rot
Sweet cherries are in bloom and are susceptible to brown rot infection. Warm and wet conditions are ideal for its growth.
Cherry leaf spot
Bract leaves have emerged on tart cherries and will be susceptible to primary leaf spot infection. The wet weather and warm temperatures in the forecast will be optimum for cherry leaf spot infection.
Fire blight
Blossom blight infection of fire blight should be kept in mind as we approach apple bloom. The Enviroweather fire blight model can be used to assess infection risk potential by choosing your closest weather station and entering date of full bloom.
Peach leaf curl
Infection of peach leaf curl can occur during bud burst stage until bud opening. The ascospores overwinter on peach tree bark and are spread to the buds by rain. Long periods of cool, wet weather favor severe infection. A fungicide should be applied at or before bud break to prevent infection.
Powdery mildew
Powdery mildew was severe in many apple and cherry orchards in 2023 and inoculum levels are expected to be high this year. Managing this disease will become critical if dry conditions return now through petal fall. Emerging leaves from buds infected last season will begin to produce conidia and result in an early secondary infection period.
American plum borer
A total of two American plum borer were caught this week at the Northwest Michigan Horticulture Research Center.
Black stem borer
First black stem borer were trapped this week at the research center with an average of four per trap. Temperatures are expected to be warm and sunny this weekend and females will likely be in flight. This is a good time for growers to manage this pest.
Green fruitworm
An average of 19 green fruitworm were caught at the Northwest Michigan Horticulture Research Center.
Oriental fruit moth
No oriental fruit moth were caught this week at the Northwest Michigan Horticulture Research Center. First catch of oriental fruit moth were reported at the Trevor Nichols Research Center in Fennville on April 15.
Spotted tentiform leafminer
An average of 23 spotted tentiform leafminer were trapped in apple orchards monitored at the Northwest Michigan Horticulture Research Center.
