East Michigan fruit update - July 17, 2018
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EmailOur spotted wing Drosophila trap catch has taken a big jump at some farms, with spider mite and apple maggot populations continuing to build. Some limited areas received rain yesterday, but most remain under drought conditions.
Weather
Dry soils remain over most of the region with drought conditions setting in for many fruit growers. Many growers have not had any significant rain in four or six weeks. Thunderstorms swept across the region yesterday, but the range of these storms was narrow and the amount of precipitation was under a tenth of an inch for most growers. Rainfall totals have been extremely variable over short distances.
Wilting of younger tree and small fruit crops is much more common this week. This week trees planted five-to-seven years ago are wilting, especially on sandy sites. Growers are spending more time and energy focusing on irrigation.
Our season is still running 10 to 14 days ahead of normal in degree day totals and about five days ahead of normal in terms of the start of harvest of our fruit crops. Degree day totals have continued to build quickly with continued hot weather.
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East Michigan Growing Degree Day Totals for March 1st to July 16th, 2018 |
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Location |
GDD42 |
GDD45 |
GDD50 |
|
Commerce (Oakland County) |
2099 |
1840 |
1426 |
|
Deerfield (Monroe County) |
2288 |
2014 |
1586 |
|
Emmett (St Clair County) |
1988 |
1734 |
1336 |
|
Flint (Genesee County) |
2224 |
1959 |
1541 |
|
Freeland (Saginaw County) |
2046 |
1786 |
1378 |
|
Lapeer (Lapeer County) |
2052 |
1795 |
1392 |
|
Pigeon (Huron County) |
1908 |
1661 |
1272 |
|
Romeo (Macomb County) |
2195 |
1932 |
1518 |
Tree fruits
Apples have surprisingly continued to size despite drought conditions for most apple growers. Apples are mostly in the range of 1.75 to nearly 2.5 inches in diameter, with most being just over 2 inches in diameter. Growers have continued hand-thinning this week and most have nearly complete hand-thinning. A few growers have begun to look at harvesting a few Lodi.
Many growers are experiencing a second week with high to very high apple maggot catch on red sticky traps. With most of our soils dry, this high apple maggot trap catch remains surprising to me. With the heat and dry conditions of the last week European red mite and two spotted spider mite numbers have continued to build quickly. A few blocks have bronzing on many trees. A few blocks are now above threshold levels, however, most blocks are only seeing limited bronzing on leaves mostly in the interior of trees. Growers need to do a good job of scouting for them.
Japanese beetle populations continue to build in most apple blocks. Green apple aphid populations have been mostly controlled with predators in the last week. Brown marmorated stinkbugs continue to be found in low numbers in traps at several farms this week. I have not found any feeding damage to fruit yet this season, however it was seen about this time last season and has been found in other parts of the state. Woolly apple aphids are continuing to move to terminal branches. Apple rust mite numbers continue to build but are generally lower than threshold numbers. Potato leafhopper adults continue to be found, with leaf curling in some blocks. At times it is hard to determine if this leaf curling is being caused by potato leafhopper or drought. We are finding good numbers of lady beetles and green lace wings this week.
Sooty blotch and fly speck symptoms are expected to be seen fairly soon in east Michigan. Most growers continue to see just a touch of fire blight.
Pears are mostly at 1 5/8 to 2 inches in diameter. A few pear blocks are starting to see pear rust mites. Pear psylla populations have continued to build in blocks where suckers have not been removed.
Peaches are mostly at 1 1/2 to 1 5/8 inches in diameter. Harvest of the earliest peach varieties continues. Redhaven harvest is expected to begin in two weeks, however they need to put on fruit size quickly, as many blocks are seeing the impact of drought on fruit size. European red mite and two spotted spider mite numbers have been building quickly in some peach blocks, with some blocks seeing bronzing. More growers have reported finding brown marmorated stinkbug (BMSB) nymphs feeding on young peach fruit. Growers need to be on the lookout for BMSB in peaches.
Sweet cherry harvest has wrapped up. Many growers are applying a post-harvest cherry leaf spot spray.
Tart cherry harvest continues for a few growers but has wrapped up for most. Many growers are applying a post-harvest cherry leaf spot spray.
Plums are about the same size as last week, with European varieties being just over 1inch in diameter and 1 ½ to 2 inches for Japanese varieties. Some European and Japanese varieties have continued to see heavy fruit drop.
Small fruits
Strawberry renovation has wrapped up at most farms. Make sure berries are watered well following renovation. Many new plantings need some attention to potato leafhopper feeding damage and weed control. Good runnering is taking place where flower buds have been removed.
Raspberry harvest continues in summer red raspberries and has wrapped up for black raspberries. A few fall raspberries are being harvested from the shorter ‘bud berry’ canes growing down deep in the row. Small fruitlets are continuing to size in fall raspberries. Berry size is a problem for summer red raspberries, as they have been impacted by drought at many farms.
Spotted wing Drosophila (SWD) trap catch has climbed quickly this past week at many farms. Growers need to be checking traps every few days to determine when SWD start their flight and when trap catches take a big jump. When you start catching flies in traps, control measures need to start shortly thereafter. I am starting to see some potato leafhopper feeding damage to new canes or primocanes in summer and fall raspberries.
Blueberry harvest is underway at most farms. Berries have not sized well over the past week, mostly due to drought conditions.
Spotted wing Drosophila (SWD) trap catch has climbed quickly this past week at many farms. Growers need to be checking traps every few days to determine when SWD start their flight and when trap catches take a big jump. When you start catching flies in traps, control measures need to start shortly thereafter. Trap catch of blueberry maggot continues for the second week. Growers need to be on the lookout for trap catch at their farm. Trap catch of its close relative, the apple maggot, was very high at several farms again this week.
Saskatoon harvest has wrapped up. Unsprayed saskatoons are seeing leafminer injury to the leaves.
Grapes continue to put on good growth, with Concord and vinifera at berry touch. Japanese beetle populations continue to build. Powdery mildew continues to be seen on leaves and twospotted spider mite populations continue to build slowly.
