Southeast Michigan fruit regional report – April 22, 2014

Spring has finally arrived with green tissue beginning to be seen in many fruit crops.

Posted on April 22, 2014 by Bob Tritten, Michigan State University Extension

Weather

With warm temperatures over the weekend, April 19-20, we continue to pick growing degree days (GDD) in short spurts. We are finally starting to see green tissue in many of our fruit crops. Our season is behind normal by about seven to 14 days, but when warm temperatures come, spring can catch up.

Soil moisture conditions are generally drying out, but remain on the wet side across the region with ground preparation or planting starting to take place. Pruning and brush chopping continues at most farms. Sprayers have mostly been tuned up for the season.

East Michigan GDD totals for March 1 to April 21

Tree fruits

Apples are starting to push first green tissue on several varieties for fruit farms to the south of Flint. None of our Michigan State University Enviro-weather stations report an apple scab infection period in rain that occurred last night (April 21) and early this morning. We did have apple spore release in last night’s rain with a low number of spores caught on spore rods. With the prediction of rain on Thursday evening (April 24) and Friday, green tissue seen on some apple varieties at most farms and spore release will most likely need to be covered for apple scab with this rain event. Varieties with more than 50 percent of the fruiting buds showing green need to be covered before the next rain event. A copper spray or a copper plus EBDC tank-mix would be a good choice to get started. If you had blocks with scab on leaves in 2013, you really should not skip covering for this rain event with any green tissue present.

If you are considering adding dormant oil, you might want to hold off until these couple of cool days forecasted are behind us by 48 hours – there is frost in the forecast for Wednesday morning this week. Remember with oil you have to be very mindful of the weather both before and after an application to avoid phytotoxicity issues. Michigan State University Extension recommends you avoid oil applications within 48 hours after a frost event or 48 hours before a freeze event.

Pears are at late bud swell. Pear psylla adults were active over the weekend with warmer temperatures.

Peaches are at early green tip for buds that were not damaged from cold temperatures this winter. It is hard to assess peach development this season as it is difficult to distinguish between simple lack of bud development and winter injury. Cambium tissue in twigs that were damaged from cold temperatures this winter is turning from light tan to darker brown.

Sweet cherries are at late bud swell to early green tip. As with peaches, I anticipate damage to flower buds due to cold winter temperatures this winter.

Tart cherries are at green tip.

Plums are mostly at bud swell.

Small fruits

Strawberry leaves continue to emerge from the crown with many being uncovered in the past week. Refer to a complete strawberry straw removal article for more details.

Raspberries are at green tip for most varieties. Canes of summer fruiting types have a significant amount of cambium browning, indicating potential winter injury. You can see this browning at the snow line at many farms. Fall raspberries have been mowed at most farms.

Blueberry buds are swollen with no green tissue being seen.

Grapes show some slight bud swell in concord types with no movement in wine grapes. There is extensive winter damage in wine grapes at most farms this spring.

This article was published by Michigan State University Extension. For more information, visit http://www.cnchemicals.com/. To contact an expert in your area, visit http://www.cnchemicals.com/, or call 888-MSUE4MI (888-678-3464).