Grand Rapids area tree fruit update – April 12, 2022

Warm weather at the beginning of this week followed by a return to cool temperatures. Most tree fruit remains fairly dormant or early silver tip. First green (bud break) may take place by the end of the week.

Gala, Honeycrisp and Fuji apple buds.
Gala, Honeycrisp and Fuji buds in Sparta, Michigan, on April 11, 2022. Photo by Anna Wallis, MSU Extension.

Weather and phenology update

In the Grand Rapids, Michigan, area, it finally feels a little like spring! A warm temperature trend is taking place at the beginning of this week, with highs in the 50s and 60s (degrees Fahrenheit) lasting from Sunday through Wednesday, April 10–14. However, temperatures are expected to cool off again on Thursday. Expect highs in the 40s and overnight lows in the low 30s.

A significant amount of rain fell over the past week, with over 1 inch recorded at the Sparta Enviroweather station, mostly on Wednesday, April 6. More precipitation is expected in the form of scattered rain and storms overnight tonight and Wednesday during the day. Cool, dry conditions are expected over the weekend, with the next chance of rain on Monday. Precipitation and soil moisture continues to be above average for this time of year. This is typically the time of year with our highest precipitation, and a time when we see recharging of the soil moisture.

Two weather systems are moving into the area, as seen in this graphic from NOAA. The first is a cold air mass from the Pacific Northwest, which is causing record-setting blizzard conditions in the Great Plains. A warm air mass is also moving northward from the Gulf of Mexico. Both are contributing to precipitation in our area.

As of April 11, the Michigan State University Sparta Enviroweather station has accumulated 93.9 growing degree days (GDD) base 42 F (GDD42). This is below average, which for is 149.1 GDD42. Last season (2021) at this time, heat accumulation was well above average with 269.7 GDD42. The projected heat accumulation through Sunday, April 17, for this season in Sparta is 130.2 GDD42. This continues to be below average, which is 195.8 GDD42.

As a result of the cool weather, conditions are expected to remain behind normal. Most buds are still dormant or at early silver tip. The first green tissue is present in warmer areas for early apple varieties such as Idared and Ginger Gold. First green (bud break) is likely to take place this week in warmer places following the warm weather through Wednesday. Average GDD42 for bud break (first green) is 127 for McIntosh. However, other varieties will be ahead or behind this, and even McIntosh varies considerably from year to year.

GDD graph

GDD42 accumulation and forecast for Sparta

Day

Date

2021

2022

Average

Su

4/17/2022

292.3

130.2

195.8

Sa

4/16/2022

286.6

129.3

188.0

F

4/15/2022

282.1

128.6

179.5

Th

4/14/2022

282.0

127.2

169.7

W

4/13/2022

281.9

124.6

162.3

Tu

4/12/2022

278.8

105.0

155.8

M

4/11/2022

269.7

96.0

149.1

Su

4/10/2022

259.0

87.8

142.5

Sa

4/9/2022

246.3

82.6

136.8

F

4/8/2022

232.9

82.6

132.5

Th

4/7/2022

212.2

82.3

127.5

W

4/6/2022

186.3

81.9

121.1

Tu

4/5/2022

166.5

76.9

114.8

M

4/4/2022

150.7

73.6

110.1

For these updates, we used averages for 1997-2021 from the Michigan Automated Weather Network (MAWN) to represent normal conditions. Weather data was gathered from MSU Enviroweather.

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.

Pest updates

We are still waiting for warmer weather to activate the pest complex for tree fruits. A couple of warmer days this week will move things forward a bit, but cooler weather is due to return and it is likely first sprays will begin after the Easter weekend.

Here are some insects to be thinking about now as you plan for monitoring and management.

Black stem borer – A few adults could begin some active this week with warmer weather and cool weather will depress flight. It’s time to think about getting traps up.

Green fruitworm – Adult flight likely to begin this week, but slow down again. This is a minor pest in managed orchards.

Redbanded leafroller – No adult flight reported in the general Grand Rapids area yet. First flight is likely 10 to 14 days out.

Spotted tentiform leafminer – No adult flight reported in Michigan. Plan to trap for it if you’ve had high numbers. Expect adult flight to begin with warmer weather, perhaps 10 to 14 days from now.

Obliquebanded leafroller – No activity of overwintering larvae reported as there is no green tissue to feed on. Once green tissue appears, monitor for small larvae in problem blocks.

Aphids - No reports of any species yet. Apple grain aphids will be the first to be seen as individuals on terminals. Rosy apple aphids usually appear around pink.

San Jose scale – Overwintering scale are present. Management sprays should be considered for orchards where scales were present on fruit at harvest and dormant oil is first management choice to consider.

European red mite – In the egg stage. Monitor for overwinter egg mortality. If eggs look pale or clear instead of bright red, they are not viable.

Climbing cutworm – No larvae reported yet; they are staying in the soil until green tissue appears. We tend to see increased damage in a cool spring and this is a minor pest in tree fruit.

Pear psylla – Adults could be present with the warmer weather of late. Expect increased adult activity near first green in pears and start management in high pressure blocks.

Fruit diseases will become a concern when green tissue is present. The first management spray for apple scab and fire blight is copper. With the cool weather in the forecast, copper sprays will give long-lasting control for both fungal and bacterial pathogens.

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