Southeast Michigan fruit regional report– August 6, 2013

Spotted wing Drosophila is now being caught in traps at most fruit farms. Blueberry, blackberry, peach, Japanese plum and summer apple harvest continues, as does a limited harvest of fall red raspberries.

Weather

Rainfall totals for the past 60 days vary widely across the region. As a general rule, 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. Put in other terms, these areas have received 150 to 300 percent above the normal rainfall over the last 60 days. Soils in many of these areas are saturated, some to a point of standing water in low lying areas. Fruit crops in these areas are suffering from these water-logged soils, with tree and small fruits wilting and in some cases dying from soil-borne diseases.

In contrast to farms described above, a few fruit farms have seen only a few inches of rain over this same 60-day period. It seems as if this is turning out to be a summer of too little rain for a few or too much rain for most fruit farms.

More slow moving thunderstorms moved across the region in the last week, brought another inch of precipitation to most fruit farms.

Cooler temperatures have persisted over the region this past week. With good soil moisture supplies, fruit have continued to size well the past few weeks.

Our season is still running just a bit behind normal in terms of growing degree day totals. We are back to normal when I look at growth stages and the start of harvest.

East Michigan Growing Degree Day Totals for March 1 to August 5, 2013

Location

GDD42

GDD45

GDD50

Commerce (Oakland)

2412

2086

1577

Emmett (St Clair)

2408

2084

1581

Flint (Genesee)

2656

2320

1799

Lapeer (Lapeer)

2438

2113

1608

Petersburg (Monroe)

2615

2274

1741

Pigeon (Huron)

2341

2024

1532

Romeo (Macomb)

2394

2077

1577

Tree fruits

Apples continue to size well where soil moisture supplies have been adequate, with many apples just more than 2.5 inches in diameter. Harvest of Pristine and a few other summer varieties continues. With cooler nighttime temperatures many apple varieties have colored a great deal in the past two weeks. Where soil moisture supplies have been adequate, terminal buds of apples have not set yet, thus it is too early to begin summer pruning in apples. In blocks where three-quarters of the buds have set, summer pruning can begin. In a week or so growers can begin to make applications of Retain in Macs and other early fall apple varieties.

I continue to catch apple maggots only on yellow sticky cards. Low numbers of codling moth continue to be caught in traps; I had expected to see these numbers climb these past two weeks for the start of the second generation adult flight. Are cool temperatures delaying this flight? I am continuing to catch low numbers of oriental fruit moth adults in traps; this is the start of the second generation flight. Fall webworm nests are continuing to be seen at a few farms. Obliquebanded leafroller larvae continue to be found in a few apple blocks. Apple rust mite numbers are continuing to drop, mainly from predators feeding on them. European red mite and two spotted spider mite eggs and a few adults continue to be seen, but in low numbers. No brown marmorated stink bugs have been trapped or reported in the region yet this season. We are continuing to see high numbers of predators this season and in the last week velvet mites are starting to be found.

Sooty blotch and fly speck symptoms continue in apples.

Pears have continued to size this past week, with most being 2 inches in diameter. Clapp’s Favorite harvest is underway. Pear psylla populations have been very high at many farms the past few weeks.

Peach harvest continues. Red Haven harvest is expected soon for growers in the southern part of the region and in a week for most others. Most peaches have good size and finish, however split pit was very common this season on early varieties. No brown marmorated stink bugs have been trapped or reported in the region yet this season. 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. A few tart cherry trees have dropped almost all of their foliage, and appear as they would in late fall. Cherry fruit fly trap catches have dropped back where a post-harvest insecticide application was made.

Plums have continued to color for European types, with most being at 1.25 inches in diameter. Shiro and 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 is complete for summer red and black raspberries and blackberry harvest continues at most farms. A few fall red raspberry farms are harvesting berries that are known as ‘bud berries’ or berries growing on short canes from lateral shoots. These early berries are not a part of the main crop.

Spotted wing Drosophila have been trapped in brambles at most farms in the region in the last week. Trap catch numbers are low, mostly in the single digits. Trap catches in both raspberries and blueberries 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. Growers need to be on the lookout for first trap catch at their farm. Lastly, the Spotted Wing Drosophila Management Recommendations for Michigan Raspberry and Blackberry Growers publication has been updated in the past few days.

Japanese beetle populations continue to build in raspberries, especially in fall red 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 late last week that received excessive amounts of rainfall in the past two months that 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 low here as well. Michigan State University Extension advises growers 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 continue, with some plantings having high numbers. Birds continue to feed heavily in most blueberry plantings and this week the feeding is being done more by starlings and red wing black birds.

Grape cane growth continues at a rapid pace. Japanese beetle populations continue to slowly build in grapes in a most plantings. Grape berry moths 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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