West central Michigan tree fruit update – April 19, 2022

Emily Lavely<lavelyem@msu.edu>, Michigan State University Extension - April 19, 2022

Winter is still lingering with a mix of rain and snowfall over the past week. Most buds remain swollen or are beginning to show side green, but a warmup this weekend will likely push growth.

Apple, peach, cherry and pear branches. — Figure 1. Stage of tree phenology for apple, peach, cherry and pear in Oceana County on April 19, 2022. Photo by Emily Lavely, MSU Extension.

Weather update

This year, April snow showers bring May flowers as winter still lingers here in west central Michigan. We’ve seen cooler temperatures with rain/snow mix throughout the region over the past week with some snow accumulation on Monday, April 18. Cool temperatures have led to a slow accumulation of growing degree days (GDD) and have kept changes in tree fruit phenology minimal (Figure 1). Based on the Hart Enviroweather station, current GDD is 89.5 base 42 F and 27.1 base 50 F. Across the region, GDD accumulation is below the five-year average (Table 1).

Table 1. Current and five-year average GDD summary from Jan. 1- April 19, 2022.
Enviroweather station	2022 GDD base 42 F	Five-year average GDD base 42 F	2022 GDD base 50 F	Five-year average GDD base 50 F
Benona/Shelby	69	107.2	20	31.1
Elbridge/Hart	81	136.5	27	45.8
Fremont	93	157.6	33	54.5
Grant*	105	143.6	39	48.5
Hart	82	136.5	27	46.2
Ludington	77	129.2	25	42.3
Mears**	86	168.7	28	61.5
New Era**	81	160.3	27	53.5

*Averages were calculated using data from 2020-2021.
**Averages were calculated using data from 2018-2021.

We will continue to see cool temperatures over the next few days. Over the weekend, there will be a warmup with highs in the 60s. Warmer temperatures this weekend will likely lead to a push in growth for most tree fruit. By Monday, April 25, Enviroweather models predict that we will see cumulative GDD at 138 at base 42 F and 43.5 at base 50 F (Figure 1).

Over the past week, we’ve had less than an inch of rainfall and drier conditions. Some growers have been able to get out into the field to put on final dormant sprays, pull out old orchard blocks, and prepare for planting new trees.

More information and reports on normal weather conditions and departures from normal can be found on the NOAA Climate Prediction Center website, NOAA U.S. Climate Normals website, NOAA Climate Normals Quick Access Page (which may be searched by region) and Midwest Regional Climate Center website.

At warmer sites, some bud development is occurring, but the movement is slow (Figure 2). Growers will have a few more days to finish pruning and prepare for bud break.

GDD line graph. — Figure 2. Cumulative and forecasted degree days for base 42 F and base 50 F for the Hart, Michigan, Enviroweather station.

Crop update

Apple varieties in Oceana County range from dormant to first green. Early varieties such as Zestar and Idared are showing signs of first green, but most buds remain dormant in the region for varieties like Gala and Honeycrisp. As a reminder, first green in apple is 127 GDD base 42 F for McIntosh based on over 30 years of observation from Sparta, Michigan; other apple varieties will be ahead or behind McIntosh. Hart is at 89.5 GDD base 42 F.

Tart and sweet cherry buds range from dormant to side green. If growers have not been able to get out in the field yet, there is still time to apply dormant or delayed dormant applications of oil or copper sprays to manage bacterial canker and early pests such as mites or scale insects.

Peaches are showing signs of swelling and side green. If growers have not already applied a spray for peach leaf curl, an application for final spring dormant sprays using copper products for management of peach leaf curl and bacterial canker is warranted in the next week.

Pear varieties are dormant or at bud swell. Dormant applications of oil can still be applied to help suppress psylla and San Jose scale populations.

Pest and disease update

With continued cool and wet conditions, it is still too cold for insect pest or disease activity in west central area orchards. I will be monitoring initial apple scab infections periods over the coming weeks.

Similarly to last week, the Trevor Nichols Research Center trapped a few adult green fruitworm this week, but green fruitworm is not a major pest. If you still haven’t applied your dormant sprays such as oil or copper, be sure to do so shortly. No disease concerns have been reported for our region.

Pests to start thinking about include:

Black stem borer
Green fruitworm
Pear psylla
Redbanded leafroller
Spotted tentiform leafminer
Obliquebanded leafroller
Climbing cutworms
San Jose scale
European red mite

For more information about regional reports, please visit the Michigan State University Extension website.

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