West central Michigan tree fruit update – April 23, 2019
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EmailCrop development updates for tart cherries, apples, peaches and sweet cherries.
Weather
After a slow start to spring, tree fruit development has moved along rapidly in the past several days as temperatures during the day topped out at nearly 70 degrees over the weekend. The drop back down to cooler weather today will slow things down a bit, but spring has arrived in the region.
Growers looking to compare this year to other years in recent memory are looking to 2014 and 2015 as the most similar years. While this spring has been late, growers feel that generally development and management schedules are seven to 10 days ahead of where they were sitting at this date last year. Five-year data from Michigan State University Enviroweather indicates these observations are on target.
|
Year |
Degree days base 42 F |
Degree days base 45 F |
Degree days base 50 F |
|---|---|---|---|
|
2019 |
125 |
87 |
45 |
|
2018 |
63 |
38 |
14 |
|
2017 |
255 |
180 |
94 |
|
2016 |
207 |
148 |
78 |
|
2015 |
145 |
101 |
54 |
|
2014 |
101 |
69 |
32 |
|
Average of five years, not including current year |
154.3 |
107.3 |
54.2 |
Crop update
Apples are anywhere from green tip to half-inch green, depending on variety and site. McIntosh is at 0.25-inch green or further in earlier locations.
Copper applications targeting fire blight and early season apple scab went out in the past week in most of the region. This product needs to be timed as close to green tip as possible in order to maximize the longevity. Primary apple scab spore discharge is ongoing, spores were captured in west central for the first time in the middle of last week.
Tart cherry buds are green and swollen, but no flower tissues or bract leaves are showing just yet. Growers still have some time before the first sprays of the season targeting cherry leaf spot need to go out.
Peach buds are just beginning to leaf out, but no flower buds have emerged or opened yet. Peach buds generally look very healthy in spite of some cold snaps over the winter that initially caused concern over flower bud survival. Many growers applied oil to peaches this year at the dormant or delayed dormant timing in the hopes of targeting San Jose scale, which has been a growing concern in the past couple of years.
We have now passed the 100 growing degree day base 42 from Jan. 1 mark for peach leaf curl applications, the time for this management practice is past. Extended wet weather in the high 40s and low 50s has made this spring an optimal season for peach leaf curl infection events.
Sweet cherry buds are green and swollen, but no leaf or flower bud tissue has emerged yet. Growers are past the time when high dormant copper rates targeting bacterial canker can be used without fear of phytotoxicity, these rates need to be scaled back as development advances. Do not to prune sweet cherries during cold, wet weather in order to avoid issues with bacterial canker development, especially on young trees. Growers who have to prune during these times are advised to leave a 6-inch stub when pruning as opposed to making a flush cut in order to limit extent of any infections to the stub instead of the trunk of the tree.
