East Michigan fruit regional report – August 16, 2016

Much needed rain has finally come to almost all of east Michigan, bringing relief from the season-long drought for most fruit growers.

Weather

Fruit growers have welcomed precipitation over the last a week. Many of our Michigan State University Enviro-weather stations have compiled between 2.5 and 3.5 inches of precipitation from three to six rains in the last week, with most of this precipitation coming over night last night. However, precipitation totals have varied a great deal over very short distances. For example, one farm in Genesee County received 4.7 inches of rain and another less than a mile away only received 2.6 inches of rain over the same four-day period. Most fruit growers have not had any significant rain events since mid-May.

The one area of the region that has not received much precipitation over the last week is the far southeastern corner of the region, mainly growers in Monroe and Lenawee counties. Precipitation totals here have ranged from only a few tenths of an inch to 1.4 inches of rain.

While it is too soon to see the effects of this precipitation on improved fruit size in apples, I would expect to see this later in the week. I also am just beginning to see tree and small plants perk up a bit after many weeks of seeing wilting and leaf drop, and in the case of younger plantings, plant death.

Degree-day totals continue to quickly build due to hot day and nighttime temperatures; we are seven to 14 days ahead of normal. In terms of the fruit crop growth stages and beginning of harvest, we are still running about five days ahead of normal.

East Michigan growing degree day totals for March 1 to Aug. 15, 2016

Location

GDD42

GDD45

GDD50

Commerce (Oakland County)

3,011

2,623

2,032

Deerfield (Monroe County)

3,316

2,902

2,265

Emmett (St Clair County)

2,945

2,568

1,993

Flint (Genesee County)

3,228

2,836

2,234

Freeland (Saginaw County)

2,935

2,563

1,992

Lapeer (Lapeer County)

2,968

2,590

2,015

Pigeon (Huron County)

2,750

2,392

1,847

Romeo (Macomb County)

3,109

2,720

2,128

Tree fruits

Apples are 2.5 to 2.75 inches in diameter for most growers, with some approaching 3 inches. As I witnessed again late last week, for the few growers that received good rains July 30, I am seeing much improved fruit size. Harvest of summer apple varieties continues, this week Paula Reds are being spot-picked for the first time at many farms. There are some sunburn issues on Paula’s, mainly for exposed fruit at the top of the tree. Also, they are coming off the limb easily, with some early drop taking place.

Many farms have extreme water core problems. I hope this is not the start for disorders with other varieties. Ginger Gold harvest is expected soon as well. Growers continue Retain applications on Gala and McIntosh, and are planning applications to other varieties soon. Many growers are reporting bird feeding injury in apples, mostly from crows.

Codling moth trap catch from the second generation adult flight has dropped back this week, which is unusual as it only began the week before. This drop off in trap catch may be caused from too much heat this past week that might be delaying flight. With codling moth flight, some seasons it is hard to tell for sure what is happening, and this is one of those years. Apple maggot trap catch on yellow sticky traps started to take off early this week, especially on farms that got good rains late last week. Apple rust mite numbers have climbed to threshold levels in a several blocks. European red mite and twospotted spider mite numbers have generally dropped this week. No additional brown marmorated stink bug trap catch has been seen this week. Beneficial numbers continue to build; this week I am seeing good numbers of lacewing eggs and velvet mites.

As I said in last week’s report, I have about a dozen apple growers that have had serious issues with fire blight this season. Half of these are in new plantings and the other half are in existing orchards where fire blight has never been seen. In all cases, I believe we are looking at trauma blight and not blossom blight. In the existing orchards, it is generally limited to a few varieties, and even here only a few strains of a variety were infected. This week, I am seeing more signs of fire blight infection in wild and abandoned apples. Black rot symptoms are on more fruit and leaves as well. Sooty blotch and flyspeck disease symptoms have not been seen, but I expect to see them soon.

Pears remain mostly 2.25 inches in diameter. Fruit size has been reduced due to the drought. Pear psylla numbers are high on suckers in untreated blocks.

Peach harvest is wrapping up for Red Haven and PF Lucky 13 at most farms. Small fruit size was an issue for the last few pickings of Red Haven at most farms; mainly due to drought. I have not seen any brown rot symptoms, but for growers who received a good amount of rain this past week, you may consider a brown rot fungicide application fairly quickly.

Sweet and tart cherry leaves continue to yellow and drop to the orchard floor, mostly due to drought and to a lesser amount from cherry leaf spot symptoms. Some sweet cherry blocks have high numbers of twospotted spider mites; they are starting to bronze leaves.

Plums have colored for European types, with fruit size mostly 1.375 to 1.5 inches in diameter. Japanese plum varieties are mostly harvested. The crop load is variable for both types, especially in some Japanese varieties, as they had little to no crop.

Small fruits

Grape fruit growth is slow. Concord fruit are starting veraison and clusters of European varieties are at berry touch. Japanese beetle numbers are declining.

Strawberry leaves are regrowing in renovated fields, especially where either rain was received or irrigation has been applied. MSU Extension encourages growers to keep new and established berries well-watered. New berries have filled the row at most farms. Potato leafhopper populations are building in new plantings. Growers need to watch for curled leaves, although this symptom can be somewhat confusing as the same symptoms can be seen with drought stress.

Raspberry harvest is ramping up for fall red raspberry varieties. Blackberry harvest is continuing at most farms. Small fruit size is an issue at farms that have been experiencing drought.

Spotted wing Drosophila (SWD) trap catch continues to be very high, with another big jump across the region. A few more farms have seen small SWD larvae in fruit and have stopped harvest for a few weeks while they bring populations under control again. Growers should protect all bramble crops on a weekly basis for SWD infestation. For more details on the SWD life cycle, control strategies and specific insecticide recommendations, consult the MSU Spotted Wing Drosophila website.

Blueberry harvest continues, although small berry size is a problem at most farms, mainly due to drought. As in the case of raspberries, trap catch of SWD in blueberries this week has taken another big jump across the region. Growers should protect blueberries for SWD infestation. For more details on SWD life cycle, control strategies and specific insecticide recommendations, consult the  MSU Spotted Wing Drosophila website.

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