East Michigan fruit update – May 21, 2019

Apple bloom is winding down in the southern few tiers of east Michigan counties. We are finally seeing bloom in strawberries across the region.

Saskatoons at petal fall
Saskatoons at petal fall. Photo by Robert Tritten, MSU Extension.

Weather

Finally, with a part of the last week with warmer temperatures, fruit crops have pushed through flowering in the southern parts of east Michigan and into bloom for most of the rest of the region. We have really taken a good jump in adding to our base 50 growing degree day (GDD) totals in the last week as well. With this being said, our season is still running between seven to 12 days behind normal when looking at both flowering stages and growing degree day totals for our Michigan State University Enviroweather stations across the region.

Most areas of east Michigan have seen some rainfall in the past week, but due to the nature of the storms that rolled through Sunday, May 19, precipitation totals have varied greatly over short distances. Most of the region saw a half-inch of rain on Sunday. Some areas saw strong winds with the storms on Sunday. No hail has been reported.

Our soil moisture conditions have generally been drier over the last week, many fruit growers finally were able to get a good amount of planting done. Many have more planting to get accomplished in the next few days. This has been one of the latest years’ growers can remember getting fruit crops planting.

With warmer to hot temperatures predicted for later in the week and over the weekend, I expect to see more rapid fruit development. With these warmer temperatures and the prediction of precipitation later in the week, I also expect to see the threat of fire blight in apples to be a concern for growers over the weekend.

East Michigan GDD totals for March 1 to May 20, 2019

Location

GDD42

GDD45

GDD50

Commerce (Oakland County)

419

310

176

Deerfield (Monroe County)

517

388

227

Emmett (St Clair County)

326

235

125

Flint (Genesee County)

463

350

206

Freeland (Saginaw County)

383

285

161

Lapeer (Lapeer County)

415

309

180

Pigeon (Huron County)

301

214

114

Romeo (Macomb County)

426

315

179

Tree fruits

Apple growth has finally taken off late last week and over the weekend. Apples in the southern parts of the region are mostly at petal fall, and in the mid-parts (Ann Arbor through Flint) are mostly at full bloom to early petal fall. With the winds on Sunday, many varieties lost a good amount of bloom. There were several good windows for pollination to occur, with good honey bee and bumble bee activity.

In the past few weeks, it is not uncommon to see some apple blocks with light or no return bloom. Further, some trees within blocks have no bloom and even individual limbs within trees have no bloom on them. This is most pronounced in Honeycrisp and Golden Delicious, but other varieties are also affected.

Insect pest pressure has picked up in the last week. New pests to report this week include first catch of San Jose scale males in traps, a few green apple aphids and a few potato leafhopper adults. Low numbers of oriental fruit moth adults continue to be caught in traps in apples and other tree fruits. Also, a few obliquebanded leafroller larvae continue to be found in apple terminals at most farms. Redbanded leafroller and spotted tentiform leafminer trap catch has dropped back again this week for both. No codling moth adults have been caught in traps.

Apple scab lesions were first seen on leaves this past Friday and Saturday (May 17 and 18), just as the MSU Enviroweather apple scab model predicted. Apple scab spore release continued in wetting events this last weekend, with the highest number of spores released just over 450 average spores per rod. Most apple growers have had two to four apple scab wetting events in the past week, with most growers having one infection period.

The Enviroweather fire blight model EIP numbers are expected to be over 100 for most growers late this week and over the coming weekend. Keep an eye out for an infection event (see “Blossom blight management for upcoming warm conditions”). With the wide variability of flower bud stages in apples this season, we will most likely see a long-extended bloom period. This variability of flowering stage might cause some challenges for fire blight control during a possible extended bloom period. With apples having a good amount of new very succulent growth in the last week, keep an eye for fire blight infection on these new shoots.

Pears are at petal fall. Pear psylla adult flight continues.

Peaches are mostly in the shuck, with a few early varieties just starting to see shuck split. While the number of viable fruits varies a great deal from farm to farm, I am pleased to see so many trees that at least have some fruit on them, even on poorer sites.

Sweet cherries are at fruit set, mostly still in the shuck, with the largest fruit being 8 to 9 millimeters is size. Most growers have a good crop of sweets coming along, but another week or so is needed to tell the entire story.

Tart cherries are at petal fall.

Plums are at petal fall for European varieties and Japanese varieties are in the shuck.

Small fruits

Strawberry bloom started over the weekend at most farms across the region. Most farms are at 20% bloom, with early flowering varieties at full bloom. Leaf growth has continued to improve. It will be late start of harvest this season. Overall, growth in strawberries has been very slow this season due to cooler than normal soil temperatures. Irrigation systems are ready for frost protection. I am planning at least one preharvest strawberry meeting this season, look for an announcement in the next week on the MSU Extension Fruit & Nuts page.

Raspberry canes continue to emerge from the soil for both summer and fall raspberries; most summer raspberries have newly emerging canes that are 10 to 16 inches in length and fall raspberries have the longest canes approaching 10 inches in length. Summer raspberries have flower buds emerging from the tips branched canes.

Blueberries are at early bloom for Jersey. Some tips of more vigorous late summer growth canes are drying up due to winter injury. Some flower buds on early varieties are not developing as they do in most years. I hope we are not seeing early signs of winter injury on these early varieties.

Saskatoons are at fruit set. Some bushes that flowered well seem to have a poor fruit set.

Grapes are at early shoot growth; most have 3 inches of new growth.

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