East Michigan fruit update – May 14, 2019

Apples are slowly inching toward bloom, which is just starting in the southern areas of the region. Most of our fruit crops are well over a week behind their normal growth stages.

Weather

Cooler temperatures over the last week have continued to hold back our season and the development of our fruit crops. Most of our fruit crops haven’t moved very much in the last week. Our season has dropped back further for the third week in a row to now being nine to 13 days behind normal when looking at both flowering stages and growing degree day (GDD) totals. Most of our Michigan State University Enviroweather stations only added a few base 50 growing degree days in the last week.

Some areas of east Michigan have seen the continuation of rain in the past week. Most of the rain occurred south of the I-69 corridor, with yet another inch of rain in four of the last seven days. Field conditions remain wet for most growers. Our soil temperatures remain below normal, thus being one of the major factors in holding back overall development of fruit crops across the region.

With warmer temperatures predicted for later in the week, I expect very rapid fruit development by the end of the week. With these warmer temperatures and the prediction of precipitation later in the week, the threat of fire blight in apples will be a concern for growers over the weekend.

East Michigan GDD totals for March 1 to May 13, 2019

Location

GDD42

GDD45

GDD50

Commerce (Oakland County)

309

220

116

Deerfield (Monroe County)

396

288

158

Emmett (St Clair County)

236

165

82

Flint (Genesee County)

343

249

136

Freeland (Saginaw County)

281

202

107

Lapeer (Lapeer County)

308

223

122

Pigeon (Huron County)

213

146

72

Romeo (Macomb County)

316

226

121

Tree fruits

Apple growth has been slow for the second week in a row. Apples in the southern parts of the region are at full bloom for Idareds, with most varieties approaching king bloom. In the mid parts of our region (Ann Arbor through Flint), apples are mostly at full pink, with a few Idareds and Gingergold at 20 to 40% king bloom. Where bloom has begun, there are not many good windows for pollination to occur.

There continues to be more variability of flower bud stages in apples this season than I have seen in a long time. This variability of flowering stage might cause some challenges for fire blight control during a possible extended bloom period, thinning with a staggered bloom and ultimately variability of apple maturity at harvest.

In the past week, I have seen more Honeycrisp blocks with little to no return bloom. Some growers believe these blocks were over cropped last year, while others report that these light blocks had a short to normal crop last season. So, the cause of this short crop in some Honeycrisp blocks is yet to be determined. There are many Honeycrisp and Golden Delicious blocks that have had a lag in flower bud development this spring as well.

Pests have been slow to develop in apples and all fruit crops over the past week. Just a few 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 buds at most farms. Redbanded leafroller trap catch has dropped back this week, as well as spotted tentiform leafminer trap catch. No San Jose scale adults have been caught in traps.

Apple scab spore discharge continued to build in wetting events this last week. Most apple growers have had two to four apple scab wetting events in the past week, with growers south of the M-59 corridor having two infection periods in the past week. Growers to the north have mostly not had an infection event in the past week. The Enviroweather fire blight model EIP numbers are expected to be over 100 for most growers over the coming weekend. With bloom and warmer temperatures expected over the weekend, keep an eye out for an infection event.

Pears are at full white to first white. Pear psylla adult flight continues.

Peaches are mostly at full bloom. The health and vigor of flower blossoms is far from normal at most peach farms this season except for peaches in the Romeo area. The number of viable buds varies a great deal from farm to farm, with poorer sites and certain varieties having few viable buds. We will see what crop remains in a few weeks.

Sweet cherries have been at full bloom for the last week. Due to cold temperatures, I have seen little to no honey bee or bumble bee activity over most of the bloom period.

Tart cherries are at full bloom.

Plums are at first bloom for European varieties, and Japanese varieties remain at full bloom over the last week.

Small fruits

Grapes are finally starting to show signs of growth; most are at bud burst.

Strawberry leaf growth has improved a great deal over the last week. Flower trusses continue to emerge from the crown and elongate, but only a few flowers have opened at farms to the south. It will be a late harvest start 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.

Raspberry canes continue to emerge from the soil for summer and fall raspberries; most summer raspberries have newly emerging canes that are 8 to 12 inches in length, and fall raspberries have the longest canes approaching 8 inches in length. Summer raspberries have flower buds emerging from the tip’s branched canes. Some summer varieties have a good amount of tip death from winter injury. This damage needs to be pruned off soon.

Blueberries are at early pink bud for Jersey, with Blueray and Bluecrop flowering behind Jersey this year. 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 petal fall to early fruit set.

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