East Michigan fruit update – April 28, 2020

Fruit growth stages have been at a standstill due to cold temperatures. Another round of recent freezing temperatures resulted in more flower bud damage in sweet and tart cherries and a few other fruit crops.

Weather

Cold temperatures over the last week have stalled fruit crop growth. This has been the case for the last two weeks. As an indication of how slow plant growth has been developing in the last two weeks, forsythia has been in bloom for almost three weeks this season. I can’t remember another year in my 40 years of working with fruit growers and keeping an eye on forsythia as an indicator plant growth that I have seen them bloom over this long of a time period. So, to say the least, growth stages are at a standstill. I predict that when temperatures do start to warm, we will get very rapid growth. I am anticipating seeing bloom in apples in eight or nine days based on the predicated temperatures over the next week.

With daily temperatures much below normal most days and nighttime/early morning temperatures still cold, our season has dropped back to being eight to 14 days behind normal in terms of growth stages and degree day totals for most fruit crops at our Michigan State University Enviroweather stations in east Michigan. This can shift around quickly in springtime, however. It appears that this cold weather will continue through the end of April into early May.

Another round of very cold temperatures was common last Wednesday morning, April 22, for most of our region. Many farms saw low temperatures in the low 20s. These cold temperatures were present for several hours. Many orchards were running frost fans that night, and some were running fans on Saturday morning as well. There was more damage to sweet cherry flower buds, some to tart cherries and much lesser damage to apples growing in low growing areas. More details follow in today’s report.

Soils continue to be unusually dry for this time of spring at most farms. Planting of tree and small fruit crops continues, and many growers are reaching out to nurseries to ship plants earlier than normal because they are ready to plant. This is unusual for us to have soils this dry for late April. These dry soils may come to an end as between 1 and 2 inches of rain is predicated over the next two days.

East Michigan growing degree day (GDD) totals for March 1 to April 27, 2020

Location

GDD42

GDD45

GDD50

Commerce (Oakland County)

166

107

44

Deerfield (Monroe County)

224

152

75

Emmett (St Clair County)

160

100

39

Flint (Genesee County)

204

136

57

Freeland (Saginaw County)

151

93

35

Lapeer (Lapeer County)

187

123

53

Pigeon (Huron County)

118

68

23

Romeo (Macomb County)

174

110

43

Tree fruits

Apple growth stages have moved only slightly for the second week in a row, most are still at tight cluster. We have had some leaf growth in the past week. Some growers call this stage squirrel ear. I have checked a good number of apple flower buds this week (although not as many as I would have checked if I have had free roam to travel during these times), and am only finding limited flower bud damage due to cold temperatures this past Wednesday morning, April 22. Damage is mainly in low growing areas on poor apple sites and is limited to 10% of flower buds killed.

Just a few apple growers have made their first fungicide application to control early apple scab, most are waiting until this next batch of rain set for tonight and tomorrow. Some horticultural oil applications have been made and others are still planned for San Jose scale and mite control. Apple pruning has wrapped up at most fruit farms with brush chopping continuing.

Pears are mostly at tight cluster with no damage from cold temperatures. I found a few more pear psylla adults flying than last week, but their numbers are generally low at this time.

Peaches have moved only slightly from calyx red stage of growth last week to first pink this week. With last Wednesday morning’s cold temperatures, I have checked a good number of peach flower buds since then and can’t see any widespread early signs of cold damage to flower buds. I am seeing some limited (10-20%) freeze damage in poor peach sites.

Sweet cherries are at open cluster to just a few at white bud stage. I can find more cold damage from last Wednesday’s freeze and the previous Thursday’s mornings freeze. Damage is limited to the most advanced flower buds. Many of the flower buds are still viable. The best way I can describe our sweet cherry crop at this time is that we have gone from a great crop of sweets three weeks ago to a good crop of sweet cherries two weeks ago to a normal crop this week, all losses due to freezing from cold temperatures.

Tart cherries are at tight cluster to early open cluster. In cutting a good number of tart cherry flower buds yesterday, April 27, I can find some damage to flower buds due to freezing temperatures last Wednesday morning. I estimate damage to be limited, in the 20-30% range.

Plums are at tight cluster for European varieties with no white tip showing yet. Japanese varieties are at first white. I am finding some freeze damage in all plum varieties, around 30% damage in European varieties and 40% damage in Japanese varieties.

Small fruits

Strawberry leaves are continuing to emerge from the crown, the leaves are well colored but still small. Some flower buds have emerged from the crown. Straw mulch is finally being removed this week. No new growth was seen in newly planted strawberries.

Raspberry growth has also been very slow again this past week, with leaves slowly emerging from the bud on some early summer red raspberry varieties, other varieties are at late bud swell. Canes continue to slowly emerge from the soil for fall bearing raspberries, most are about an inch in length.

Blueberries are at early tight cluster. There has been some damage to flower buds in Jersey but none in Blueray or Bluecrop varieties.

Saskatoons are at tight cluster to a few flowers being at pink to early white tip.

Grapes are unchanged this week and are still at bud swell.

Haskaps are at full bloom for most flower buds to a few of the earliest flowers at petal fall. They flower over a long period of time.

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