Southeast Michigan fruit regional report– Aug. 13, 2013

Spotted wing Drosophila continues to be caught in traps at most fruit farms across the region. Blueberry, peach, Japanese plum, fall red raspberry, blackberry and summer apple harvest continues.

Weather

More slow moving thunderstorms moved across the region in the last week, bringing another inch of precipitation to most fruit farms. The storms moved over different parts of the region on different days of the week. Pea- to marble- size hail was reported in several of these storms.

Rainfall totals for the past 60 days vary widely across the region. As a general rule, areas in the very eastern parts of Monroe, Wayne and Macomb counties have received between 12 and 16 inches of rain over this same 60-day window. Even in these areas, precipitation totals vary greatly over short distances. Fruit crops in these areas are suffering from water-logged soils, with tree and small fruits wilting and in some cases dying from soil-borne diseases.

Cooler temperatures have persisted over the region this past week. Our season is running just a bit behind normal in terms of growing degree day totals, and close to normal to a few days behind normal when I look at growth stages and the start of harvest of fruit crops.

East Michigan Growing Degree Day Totals for March 1st to August 12th, 2013

Location

GDD42

GDD45

GDD50

Commerce (Oakland)

2583

2236

1692

Emmett (St Clair)

2578

2234

1695

Flint (Genesee)

2836

2480

1923

Lapeer (Lapeer)

2606

2260

1720

Petersburg (Monroe)

2796

2435

1867

Pigeon (Huron)

2504

2167

1639

Romeo (Macomb)

2575

2237

1701

Tree fruits

Apples continue to size well where soil moisture supplies have been adequate, with many apples just over 2.65 inches in diameter. Harvest of Jersey Mac, Vista Bella and other summer varieties continues. I have been in several apple blocks in the past week where terminal bud set has taken place, so summer pruning can begin. As a rule of thumb, when three-quarters of the buds have set, summer pruning can begin. Growers can begin to make applications of Retain in Macs and other early fall apple varieties as we are about four weeks from beginning of harvest of these varieties.

With the large fruit size in apples this season, I am concerned about the possible development of bitter pit in large fruit. Michigan State University Extension reports growers need to consider additional applications of calcium in cover sprays.

Codling moth trap catch finally began last week for the start of the second generation flight. Trap catch numbers are generally in the range of 8 to 12 moths per trap. Most growers had enough trap catch to biofix for the second generation flight. I continue to catch good numbers of apple maggots, but only on yellow sticky cards. I am continuing to see low numbers of many other insect pests, including; oriental fruit moth adults, fall webworms, obliquebanded leafroller larvae, Japanese beetles, wooly apple aphids, potato leafhoppers and green apple aphids. Apple rust mites continue to be found, with their numbers dropping, mainly from predators feeding on them. European red mite and two spotted spider mite eggs and a few adults continue to be seen, generally in low numbers. No brown marmorated stink bugs have been trapped or reported in the region this season. There continues to be high numbers of predators seen this season.

Sooty blotch and fly speck symptoms continue in apples.

Pears have continued to size this past week, with most being 2.25 inches in diameter. Clapp’s Favorite harvest is complete at most farms. Pear psylla populations have been very high at many farms the past few weeks.

Peach harvest continues, Red Haven harvest started late last week at most farms. Most peaches have good size and finish, however some growers are reporting a wide spread in fruit size this year and with all of the rainfall we have received, are wondering why fruit size is not more uniformly large. I suspect that we may have had a bit more winter injury in tree trunks than we had expected.

No brown marmorated stink bugs have been trapped or reported in peach in the region yet. Brown rot has been seen at a few farms in the past week, but only in blocks that have received hail in the past month or so. Peach scab has been seen in the last week in a few blocks. Fruit, twigs and branches continue to ooze from bacterial spot infection. X disease continues to be seen.

Sweet and tart cherry leaves continue to turn yellow and drop to the orchard floor in blocks where post-harvest cherry leaf spot sprays have not been applied.

Plums have continued to color for European types, with most being at 1.25 inches in diameter. Santa Rosa and other Japanese varieties continue to be harvested.

Small fruits

Strawberries continue to rebound from renovation. Newly planted berries are continuing to runner well. Potato leafhopper feeding and leaf curling is being seen in most new plantings. In areas where heavy rains have occurred in the past 60 days, growers are seeing high numbers of plants killed in low lying areas from black root rot disease.

Raspberry harvest of fall red raspberry and blackberry continues. Spotted wing Drosophila have continued to be caught in traps at most farms in the region in the last week. Trap catch numbers are beginning to rise. Trap catches in both raspberries and blueberries are very high in southwest Michigan in the last two weeks and I expect to see trap catch numbers quickly climb in our region in the next two weeks. Growers need to be on the lookout for first trap catch at their farm. Japanese beetle populations have started to drop in the past week in raspberries. Leaf curling from potato leafhopper is being seen in both new and established raspberry plantings.

I have been at a few fall red raspberry farms in the last few weeks that received excessive amounts of rainfall in the past two months that now have plants collapsing from Phytophthora root rot disease.

Blueberry harvest continues on many varieties, with an excellent crop being harvested. Spotted wing Drosophila have been trapped in blueberries at several farms in the last week. Trap catch numbers are starting to rise. Growers need to be on the lookout for first trap catch at their farm. Trap catches in both blueberries and raspberries are very high in southwest Michigan this week and I expect to see trap catch numbers quickly climb in our region in the next two weeks. Blueberry maggot trap catch on yellow sticky traps continues, with some plantings having high numbers. Birds, mostly robins, starlings and red wing black birds, continue to feed heavily in most blueberry plantings.

Grape cane growth continues at a rapid pace. Japanese beetle populations are dropping in grapes. Grape berry moth adults continue to be caught in traps. Downy mildew continues to be seen in many grape plantings as a result of cool wet weather.

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