Southeast Michigan fruit update – April 18, 2023
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EmailWe seem to have experienced four seasons in the last week.
Welcome to the third in-season fruit article update for southeast Michigan for the 2023 season. Throughout the season these updates will include information about the weather in the past week and the upcoming week, a fruit-by-fruit guide to current conditions with appropriate pest and disease updates, and other relevant observations.
General observations
The warm weather we had last week has pushed many of our fruit crops along very quickly in their bud development. We are even seeing bloom in sweet cherries, peaches, and plums in some parts of the region. With temperatures dropping tonight and into the weekend close to some critical temperatures you will need to be watchful. It may help to review this Michigan State University Extension article on what to do if a freeze is coming.
The continued chance of rain means that disease risk will still be present. Based on the RimPro models at the Romeo station, we are expecting the potential for apple scab infection tonight and over the weekend. The risk of economic loss due to scab is highest early in the season because it is a disease that will recur and intensify with successive generations.
The trap line monitoring has started at Trevor Nichols Research Center in Fennville, Michigan. In addition to green fruitworms flying, there have been flights of both redbanded leafroller and spotted tentiform leafminer. There has not been a catch of oriental fruit moth, although models suggest that the biofix date may have already happened.
Plans are being made for the southeast Michigan trap line to start later this spring. I have reached out to a few growers already, but I am still looking for a site with cherries (sweet or tart) somewhere north of Flint, MI, so please contact me if you have any.
I encourage our growers to register and attend the weekly southern Michigan fruit grower meetings virtually on Monday evenings. It is a good opportunity to ask questions and receive RUP credits. See the latest weekly fruit meetings for southern Michigan on MSU’s Kaltura Mediaspace (these may take a few days to upload after the Monday meetings).
Fruit-by-fruit conditions
Apples: We have jumped quite a bit ahead in our growing degree day accumulation. Pink has been reported in apples near our warmest Enviroweather station at Deerfield. Further north in Novi we are mostly at tight cluster with a few early cultivars in pink, including IdaRed, Zestar and Pink Lady. In both Fenton and Romeo on Monday the apples were primarily at tight cluster. Scab sprays should be applied at the next opportunity as we break dormancy. RimPro is currently reporting a risk of a scab infection events both tonight and over the weekend.
Powdery mildew season starts with half-inch green and rust season starts around pink, so you may need to use a product with a broader effect. Given the chance of rain nearly every day this week, you may need to add a sticker type spray adjuvant that will make the spray less prone to wash off. Critical temperatures for apples at tight cluster are 27 degrees Fahrenheit for 10% kill and 21 F for 90% kill. At the full pink stage, they are 28 F for 10% kill and 25 F for 90% kill.
Blueberries: We have early green tip in blueberry plantings in Fenton. This is the primary risk period for mummy berry and it is time to start paying attention to phomopsis. FRAC 3 fungicides are reported to be efficacious for both mummy berry and phomopsis. The critical temperature for damage for blueberries at bud swell is 10-15 F and for tight cluster 20-23 F.
Brambles: We are seeing growth in both red and black raspberries in Washtenaw County and Romeo as well as in southwest Michigan. We are still at pre-bloom, so there is still time for delayed dormant sprays. See the MSU Extension Fruit Management Guide (E-154) for more information.
Cherries: We are seeing bloom in sweet cherries in Romeo as well as open cluster to white stages in tart cherries in Novi, Fenton and Romeo. Copper sprays aren’t recommended past the pre-bloom stage because of phytotoxicity. Expansion of first bract leaves (beginning of risk period for cherry leaf spot) is expected 250 DD Base 42 after Jan. 1. We are expecting to reach 250 in the next week (see GDD table in the weather update table) The critical temperatures for sweet cherries at full bloom are 28 F for 10% kill and 25 F for 90% kill. The critical temperatures for tart cherries from open cluster to full bloom are 28 F for 10% kill and 24 F for 90% kill.
Grapes: No movement yet. Dormant sprays are still effective.
Strawberries: In southwest Michigan, bloom is starting on protected plants. Flowers can be killed at 10 F temperatures while still in the ground at 20 F temperatures once emerged. Early season fungicides should focus on controlling leaf spot.
Peaches and nectarines: Peaches in Fenton are at the pink stage while we are already seeing peaches blooming in Romeo. At first pink the critical temperatures for peaches are 25 F for 10% kill and 15 F for 90% kill. At full bloom they are 27 F for 10% kill and 24 F for 90% kill.
Pears: Pears in Novi are at the tight cluster stage. Some pear psylla has been spotted in west central Michigan. At tight cluster, the critical temperatures for pear are 24 F for 10% kill and 15 F for 90% kill.
Plums: European plums observed in Fenton are blooming. Prune out black knot and dispose of the knots by burning or removing from the orchard. Sanitation is an important step in managing this disease. The critical periods for most fungal control is for petal fall to late June, but for brown rot specifically the critical times are during bloom and later on at fruit coloring. The critical temperatures for European plums in full bloom are 28 F for 10% kill and 23 F for 90% kill.
Insect conditions
In tree fruit, our insect concerns include mites, scale, rosy apple aphid, tarnished plant bug, green fruit worm, oriental fruit moth, obliquebanded leafroller and black stem borer. More in-depth information can be found by watching the latest weekly fruit meetings for southern Michigan on MSU’s Kaltura Mediaspace (these may take a few days to upload after the Monday meetings).
Black stem borer: Main control is to target emerging females as they search for new sites to deposit eggs, which should be in the coming weeks.
Oriental fruit moth: It is time to think about mating disruption before emergence.
Pear psylla: We are likely past the time for early control with dormant oil. Later on, control requires reducing vegetative flushes and hand removing suckers.
Redbanded leaf roller: Flight detected at the Trevor Nichols Research Center.
Rosy apple aphid: Check for colonies in fruit clusters when we get to the pink stage. If necessary, use a pre-bloom insecticide for control.
San Jose scale: We are likely past the time for early season dormant oil applications. The next opportunity to control them is during their crawler stage around the second cover in apples.
Spotted tentiform leafminer: Flight detected at the Trevor Nichols Research Center.
Tarnished plant bug: Pyrethroids are the most effective pink stage spray.
Seasonal weather update
We seem to have experienced four seasons in the last week. We have had a big jump in our growing degree day accumulation. We have had little liquid precipitation in the last week (see table below), though there has been some snow. We haven’t quite had temperatures low enough to cause any concern for our crops, but it will be wise to stay alert to changing weather conditions in the next week.
|
Liquid Precipitation Accumulation Mar. 1 - Apr. 17, 2023, issued Apr. 17, 2023 |
||||
|
Station (County) |
Rainfall Total (in.) Current |
Hours with Rainfall Current |
Rainfall Total Average (5 Yr.) |
Hours with Rainfall Average (5 Yr.) |
|
Commerce (Oakland) |
5.5 |
100 |
3.3 |
78 |
|
Deerfield (Monroe) |
4.3 |
86 |
3.7 |
82 |
|
Emmett (St. Clair) |
6.1 |
101 |
3.0 |
89 |
|
Flint (Genesee) |
6.0 |
97 |
3.4 |
87 |
|
Freeland (Saginaw) |
. |
. |
7.1 |
80 |
|
Hudson (Lenawee) |
3.4 |
86 |
3.8 |
93 |
|
Lapeer (Lapeer) |
2.9 |
64 |
3.4 |
80 |
|
Pigeon (Huron) |
3.9 |
65 |
3.2 |
84 |
|
Romeo (Macomb) |
5.4 |
100 |
3.1 |
70 |
|
Average of stations in this region: |
4.7 |
87 |
3.8 |
83 |
|
Difference in Liquid Precipitation Accumulation from Mar. 1 observed Apr. 10, and April 17, 2023; issued Apr. 17 |
||||||
|
Station (County) |
Rainfall Total (in.) April 10 |
Rainfall Total (in.) April 17 |
Difference from April 10-17 |
Hours with Rainfall April 10 |
Hours with Rainfall April 17 |
Difference from April 10-17 |
|
Commerce (Oakland) |
5.4 |
5.5 |
0.1 |
94 |
100 |
6.0 |
|
Deerfield (Monroe) |
4.1 |
4.3 |
0.2 |
78 |
86 |
8.0 |
|
Emmett (St. Clair) |
5.5 |
6.1 |
0.6 |
93 |
101 |
8.0 |
|
Flint (Genesee) |
5.9 |
6.0 |
0.0 |
95 |
97 |
2.0 |
|
Freeland (Saginaw) |
. |
. |
. |
. |
. |
. |
|
Hudson (Lenawee) |
3.3 |
3.4 |
0.1 |
80 |
86 |
6.0 |
|
Lapeer (Lapeer) |
2.8 |
2.9 |
0.1 |
63 |
64 |
1.0 |
|
Pigeon (Huron) |
3.5 |
3.9 |
0.4 |
60 |
65 |
5.0 |
|
Romeo (Macomb) |
5.2 |
5.4 |
0.2 |
92 |
100 |
8.0 |
|
Average of stations in this region: |
4.5 |
4.7 |
0.2 |
82 |
87.4 |
5.5 |
In the short term, we are expecting lows tonight (Tuesday, April 18) from 29-32 F and showers late in the day on Wednesday and a warm front coming through from Thursday to Friday with highs in the 70s F. This will be followed by a new cool weather system over the weekend into Monday with rain on Friday and Saturday and the potential for freezing temperatures on Sunday and Monday. There is a chance of rain almost every day this week and the potential for wind may make it difficult to find a suitable day for spraying.
In the medium term, we are looking at both the mean temperatures and precipitation dropping below normal. The long lead outlooks are still calling for warmer and wetter than normal conditions for the late spring and summer seasons.
Our regional average growing degree day accumulation for the season has jumped ahead of the five-year average by 74 GDD at 42 F, 67 GDD at 45 F and 56 GDD at 50 F (see table below). This is a stark comparison to last week when we were 21 GDD behind the average at 50 GDD accumulate when average temperatures for the day exceed the base temperature of the model. So, even though we have seen a warm winter, the temperatures have consistently stayed below the those needed to gain many degree days. Read this Michigan State University Extension article to learn more about degree days: Understanding growing degree-days.
|
Degree Day Accumulation Mar. 1 - Apr. 17, 2023, Forecast from Apr. 18-Apr. 23, 2023; issued Apr. 17 |
|||||||||
|
Station (County) |
Degree Days Base 42 F Current |
Degree Days Base 42 F Average (5 Yr.) |
Degree Days Base 42 F Forecast |
Degree Days Base 45 F Current |
Degree Days Base 45 F Average (5 Yr.) |
Degree Days Base 45 F Forecast |
Degree Days Base 50 F Current |
Degree Days Base 50 F Average (5 Yr.) |
Degree Days Base 50 F Forecast |
|
Commerce (Oakland) |
203 |
134 |
248 |
157 |
95 |
191 |
105 |
51 |
125 |
|
Deerfield (Monroe) |
237 |
175 |
294 |
183 |
127 |
227 |
117 |
72 |
144 |
|
Emmett (St. Clair) |
198 |
127 |
239 |
155 |
93 |
185 |
104 |
52 |
121 |
|
Flint (Genesee) |
234 |
154 |
277 |
183 |
111 |
215 |
123 |
61 |
142 |
|
Freeland (Saginaw) |
193 |
114 |
227 |
152 |
81 |
175 |
103 |
44 |
116 |
|
Hudson (Lenawee) |
208 |
153 |
260 |
159 |
112 |
200 |
104 |
63 |
129 |
|
Lapeer (Lapeer) |
224 |
141 |
265 |
175 |
102 |
205 |
118 |
57 |
136 |
|
Pigeon (Huron) |
188 |
97 |
215 |
151 |
68 |
168 |
106 |
36 |
114 |
|
Romeo (Macomb) |
214 |
136 |
261 |
167 |
96 |
201 |
110 |
51 |
131 |
|
Average of stations in this region: |
211 |
137 |
254 |
165 |
98 |
196 |
110 |
54 |
129 |
|
Difference in Degree Day Accumulation from Mar. 1 observed Apr. 10, and April 17, 2023; issued Apr. 17 |
|||||||||
|
Station (County) |
Degree Days Base 42 F April 10 |
Degree Days Base 42 F April 17 |
Degree Days Base 42 F Difference |
Degree Days Base 45 F April 10 |
Degree Days Base 45 F April 17 |
Degree Days Base 45 F Difference |
Degree Days Base 50 F April 10 |
Degree Days Base 50 F April 17 |
Degree Days Base 50 F Difference |
|
Commerce (Oakland) |
71 |
203 |
132 |
43 |
157 |
114 |
19 |
105 |
86 |
|
Deerfield (Monroe) |
107 |
237 |
130 |
71 |
183 |
112 |
32 |
117 |
85 |
|
Emmett (St. Clair) |
59 |
198 |
139 |
35 |
155 |
120 |
14 |
104 |
90 |
|
Flint (Genesee) |
88 |
234 |
146 |
54 |
183 |
129 |
25 |
123 |
98 |
|
Freeland (Saginaw) |
59 |
193 |
134 |
35 |
152 |
117 |
16 |
103 |
87 |
|
Hudson (Lenawee) |
90 |
208 |
118 |
57 |
159 |
102 |
27 |
104 |
77 |
|
Lapeer (Lapeer) |
81 |
224 |
143 |
50 |
175 |
125 |
23 |
118 |
95 |
|
Pigeon (Huron) |
50 |
188 |
138 |
31 |
151 |
120 |
15 |
106 |
91 |
|
Romeo (Macomb) |
73 |
214 |
141 |
44 |
167 |
123 |
17 |
110 |
93 |
|
Average of stations in this region: |
75 |
211 |
136 |
47 |
165 |
118 |
21 |
110 |
89 |
Watch Jeff Andresen's Biweekly Agricultural weather forecast reports.
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.
