Grand Rapids, Mich., area tree fruit regional report – April 2, 2013

Growers are getting ready for the 2013 apple growing season.

What a difference a year can make. We’ve all heard that statement before and it’s certainly fitting in the tree fruit business when comparing the spring of 2012 to spring of 2013. It’s what we’ve come to expect from Michigan weather and this spring is certainly easier to deal with.

Growing degree day totals for the general west Michigan area are running behind normal averages, but for this time of year, these extreme annual differences can change quickly. An average date for green tip in MacIntosh is April 11. The forecast indicates that we might be about a week behind for normal green tip. For more information, read the Michigan State University Extension article "Predicting first green in apples for West Michigan."

Tasks that need to be done soon in tree fruits include:

  • Finish pruning and get brush out of orchards. This would be a great week to finish pruning dwarf sweet cherries.
  • Get sprayers up and going.
  • Order insect traps and lures.
  • Be ready to apply peach leaf curl sprays at a delayed dormant timing.
  • Copper applications on sweet cherries should be timed for before or right at bud break – important to do in 2013 after the devastating bacterial canker of 2012.
  • Thinking ahead about your GAP audit for 2013 – many did not do one for 2012, so it will need updating. Water testing could be done for 2013 right now.

Tree fruit diseases

There was more disease in orchards than normal in 2012 due to reduced cover sprays in no crop situations. This means there is likely more inoculum for apple scab and powdery mildew coming into 2013.

It would be wise to not miss the earliest apple scab infections or “let them go” because spore numbers were low or there is “hardly any green showing.” Any early lesions that get started lead to much higher inoculum levels in May and June. You can spray one or two more times on the early side of the season or all summer long if you miss something.

Copper use in apples for the earliest apple scab spray is highly recommended this season. Copper is an excellent scab material and there are many formulations and they are all very different. Growers should examine the labels of the products as they differ greatly in their metallic copper concentration. (See the MSU Extension article “Copper formulations for fruit crops.”)

Powdery mildew was at record-high levels in many tree fruit blocks in 2012 and earlier cover sprays (perhaps tight cluster) will be needed to prevent it in 2013, especially if we get the right conditions at the right time. Be sure to consider the mildew efficacy of fungicides you choose this season.


No activity to report for tree fruit insects. European red mite eggs can be found, but numbers appear to be normal or even lower than normal so far. Blocks that had high numbers of mites late in 2012 should be checked carefully for red mites.

Some apple and peach blocks had unusually high numbers of San Jose scale in 2011 and 2012. Delayed dormant oil sprays are still the best management tool for scale pests, but they do come with risks, not to mention difficulty in application.

Meeting notices

Spring Spray Meeting is Thursday, April 18, from 4-6 p.m. at Goodfellow Orchards near Sparta, Mich. It’s the same location as last year. This meeting is open to everyone.

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