May 14, 2013

Michigan frost damage doesn’t appear to be severe

Early indications are that Michigan’s apple crop escaped widespread damage from overnight frost May 13, particularly in the Fruit Ridge area north of Grand Rapids.

Amy Irish-Brown, a Michigan State University (MSU) Extension educator, said that except for some low spots where temperatures dipped into the mid-20s for a more extended period of time, “right now we’re sitting pretty good.”

“There will be some damage, but it’s really too early to tell,” Brown said. “I anticipate we will have a full crop for apples. There’s at least 30 to 50 percent of the bloom that is still nice and green. Being in bloom, we assume they will pollinate and be enough. Apple trees don’ t need very many actual viable flowers to have a full crop.

“Another strange factor is that the trees are extremely healthy coming into this year,” Brown said. “I don’t remember in my lifetime a bloom with so many leaves present, three to four inches at a time. This will give the trees some added energy and it protected the flowers a little bit from the frost. The bottom-line story is we’re looking pretty good.”

Apple growers used a variety of frost mitigation efforts, including wind machines, orchard heaters and brush fires, to ward off the cold temperatures, Brown said.

“(Growers) didn’t have anything to lose. There were micro sprinklers used on only a few acres. Helicopters were used in areas where they have deeper pockets and larger acreage.

“The prediction was for it to be pretty darn low, and we were lucky it didn’t get colder. The frost fans were started at 11 p.m. (the previous night) when it was colder and calmer,” she said.

“There was a little bit more injury seen up in isolated areas of Benzie County where it got pretty cold. But even with six out of 10 buds injured, that still leaves four in a cluster. In a couple of weeks we will be able to see what the fruit set looks like.”

The lack of extensive damage to the crop was comforting to growers after a late frost wiped out most of Michigan’s apple crop last year. Predominately ideal spring conditions thus far in 2013 enabled trees to put on extra blossoms.
Brown said that with the long-term outlook not indicating any frost likelihood, “we can now turn our attention to things like fire blight and blossom blight as temperatures move toward the 80s.”

Frost damage in northern lower Michigan appeared to be minimal, according to Nikki Rothwell, coordinator of MSU’s Northwest Michigan Horticultural Research Center and a district Extension educator.

“There is likely some isolated areas that have a little damage from the cold Sunday/Monday temperatures, but I think it is not too extensive,” Rothwell said. “I saw some damage in apple in a low site, but most cherries I have looked at are still good. I also heard some apples were hit closer to the lake in Manistee County, but again, I think the damage is not extensive.”

In southwest Michigan, the widespread radiation freeze with lows in the upper 20s caused light damage across the region, according to Mark Longstroth, MSU Extension small fruit educator.

Light damage in the low sites or in the low areas in orchards has been reported across the region.

“Severe damage was reported in parts of eastern Van Buren County,” Longstroth indicated. “It will take some time to assess the extent of the damage.”

Tree fruit in southwest Michigan are generally past full bloom. The low temperatures on the morning of May13 damaged apples more than other tree fruit.

“Little freeze damage was reported in cherries,” Longstroth said. “Apparently the fact that the trees had good foliage and the fruit was in the shuck protected the fruit from the cold.

“Sweet cherries did suffer a little freeze injury, but the extent of the damage will not be apparent until after the end of the post-bloom June drop,” according to Longstroth.

“In grapes, it is too early to assess the full extent of injury to vineyards from Monday morning’s freeze,” Longstroth reported. “There was significant damage in a few sites, but most sites suffered only light damage.”

Bloom for blueberries “looks to be very heavy and it seems there was little damage from Monday’s freeze.”

Longstroth indicated most strawberry growers used their sprinkler systems to protect against freeze injury on Monday, and “little damage has been reported from this freeze.”

– Gary Pullano