Southeast Michigan fruit regional report – June 24, 2014

Strawberry harvest continues and early ripening sweet cherry varieties are expected to start harvest in the next few days. Growers need to keep an eye on spotted wing Drosophila traps for first catch.

Weather

Warmer temperatures have persisted over the last week, with good amounts of rainfall coming to a few farms. Our season remains close to normal for growing degree day totals. It is interesting to note that most strawberry farms had one of their latest beginnings of harvest on record and that sweet cherries appear to be ripening at least a week earlier than normal.

Most of the region received around one inch of rain spread over three to four days in the last week. Some farms saw very heavy rain last Wednesday afternoon, in the range of two to three inches in a short time span. Despite these rain events of the last week, many of our soils remain a bit on the dry side. Growers continue to irrigate newly planted tree and small fruit blocks on a regular basis. Reports of pea to marble sized hail from Wednesday’s thunderstorms were common across the region.

East Michigan GDD totals for March 1 to June 23, 2014 

Location

GDD42

GDD45

GDD50

Commerce (Oakland)

1250

1043

743

Emmett (St Clair)

1232

1025

729

Flint (Genesee)

1396

1176

858

Lapeer (Lapeer)

1282

1075

778

Petersburg (Monroe)

1392

1176

859

Pigeon (Huron)

1140

 946

667

Romeo (Macomb)

1307

1093

783

Tree fruits

Apples in the Flint, Michigan area are mostly at 1.375 inches. June drop is now under way, with a good amount of fruit dropping. There is great variability in crop load from variety to variety, block to block and even tree to tree. Hand thinning will be required on some varieties. Most growers are reporting a spotty apple crop with wide swings in crop load between varieties. Winter injury and tree collapse from extreme cold winter temperatures continues to be seen; refer to last week’s report for further details.

San Jose scale crawlers are just starting to become active, mostly on tree trunks at this time. Male trap catch has continued to drop back. Codling moth and oriental fruit moth trap catch have continued to drop back. Michigan State University Extension reminds growers that the time to control egg hatch based on biofix dates is quickly approaching. Obliquebanded leafroller feeding on leaves has caused a fair amount of damage in many apple blocks over the last three weeks, although the numbers of larva are quickly declining as is adult trap catch. Woolly apple aphids, green apple aphids and rosy apple aphids continue to be seen in low numbers. Potato leaf hoppers continue to be found in good numbers at just a few farms, with a few blocks starting to see hopper burn to leaves. Good predator numbers continue to be seen in most apple blocks.

Primary apple season has ended with no spores being caught in spore traps from rainfall last Wednesday, June 19. Apple scab lesions continue to be found in light amounts at many farms. Black rot infected fruit are just starting to be seen in just a few apple blocks, always in close proximity to infected mummies from last season. No frogeye leaf spot symptoms are being seen on leaves as of yet. This is the only new disease to report in apples this week. Small branches on the insides of trees are starting to curl from fire blight infection. In previous reports, I indicated that a few larger branches were dying. Powdery mildew symptoms continue to be found in a few apple blocks; most growers have done a good job of bringing it under control after heavy infection levels last season.

Pears are at 1.25 inches, with a good crop coming along on most varieties. All stages of pear psylla continue to be seen, with a good nymph hatch in the last week.

Peach pruning continues at most farms related to winter injury. It is vital that growers leave as much foliage as possible on trees that have some leaf growth, as leaves will help foster healing. Dead trees can be removed, however if growers are considering filing a claim with the USDA Farm Service Agency for TAP funds, the trees need to be counted first.

Sweet cherries are at 21 to 23 millimeters; growers are expecting to begin harvest in the next few days on early varieties. This is at least a week ahead of the normal beginning of harvest. Most growers report having 20 percent of a crop at best this season. Birds, mostly robins, are already feeing heavily on the few fruit that we have this season. Spotted wing Drosophila traps need to be set in sweet cherries. Larger scaffold limbs on stressed sweet cherry trees continue to collapse from winter injury. Here again as is the case in peaches, the cambium is a dark brown color from winter injury.

Tart cherries are mostly at 18 to 20 millimeters, with a wide spread of fruit sizes. Fruit are turning from a straw color to red. I thought that much of this early maturing fruit was going to drop early, but this does not seem to be the case. Most growers have 40 percent of a crop of tart cherries this season.

Plums are mostly at one inch for European types with a good amount of fruit drop in the last two weeks. Japanese plums have mostly dropped in the last week, with remaining fruit mostly at 1.25 inches.

Small fruits

Strawberry harvest continues, with farms in the southern part of the region hoping that harvest will continue for another week. Where rain and/or irrigation have been in good supply for the last week, berry size has been good. Gray mold is being seen in isolated hotspots at many farms in the last few days. A fungicide application is needed in these spots to try to arrest the problem and growers need to be closely monitoring other planting for possible spread. I have been at a number of farms where strawberry plants have collapsed just as berries are ripening and/or have small stunted leaves and fruit. I now believe the root cause of this problem is related to winter injury to the crown of the plant.

Raspberries are nearing harvest for the earliest maturing varieties, with enlarging green fruit on most summer fruiting types and fall bearing varieties are at 30 to 36 inches in length. A few flower clusters are just starting to be seen on fall bearing raspberries. Spotted wing Drosophila traps need to be set in summer raspberries.

Blueberries are mostly at 8 to 10 millimeters. Winter damage is showing up at more farms in the last two weeks, some with twig death and others with entire canes dying back to the ground. This damage is variety specific and is not uniform from farm to farm. Where canes are dead to the ground, I suggest removing all of the canes and starting the bush all over again. It will take a few years for the bush to rebound and become productive again. This renovation style of pruning can be done with a chain saw or flail mower and needs to take place as soon as possible.

Grapes are at late bloom to buckshot berries for Concord and Niagara varieties, with a wide range of development stages this season. Wine grapes continue have extensive cane death in most varieties, but new shoots continue to emerge from latent buds on the trunk. It is still a bit early to prune these back; I hope to see more buds break in the next few weeks. Grape berry moths are starting to be caught in traps.

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