SW Michigan Fruit Update
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Southwest Michigan, May 5, 2009

Mark Longstroth, Bill Shane

Weather

The weather last week was wet and cool with highs in the 60s and lows in the 40s.  Monday and Thursday were wide spread infection events for several diseases.  Soils are wet.  Weekend temperatures were not low enough to cause harm to open blossoms or fruit.  Rain is forecast for Wednesday.

Southwest Michigan Growing Degree Day Totals March 1 through May 3, 2009				Grapes, from April 1
Location	GDD 42	GDD 45	GDD 50	GDD 50
SWMREC:	311	233	135
Fennville:	380	290	175

You can find weather and IPM information for Southwest Michigan at the Enviroweather website.  Here is a link a table of SW Michigan’s Growing Degree-Days from March 1 to May 2, 2009.  Our heat accumulations are close to average; here is a comparison of Growing Degree Days to May 3 in past years.  There are also maps showing the current Degree-day accumulations for the state and the departure from the long term average.  

Tree fruit

Bloom is underway in stone fruit and growers need to protect against blossom brown rot in peaches, sweet cherries and plums.  This disease requires wet and warm conditions, and only 5 to 6 hours of wetness at 70F.  .

Apricots are in the shuck.  Many growers report they have a good crop.

Peach bloom is ending.  There was a heavy bloom and the crop looks good.  No more than 0.25 pounds of metallic copper for to reduce bacterial spot at this time.  Peach leaves are emerging and symptoms of peach leaf curl should be visible soon.  Oriental fruit moth flight has begun and egg laying will begin this week.  Nectarine growers should scout for western flower thrips.

Sweet cherry bloom is ending and many leaves are out.  Sweet cherry blossoms and fruit are always susceptible to brown rot.  Because the leaves are out growers also need to protect against cherry leaf spot.  Growers should scout for plum curculio as the fruit emerges from the shuck next week.  Plum curculio generally begins egg laying when we have warm night temperatures.

Tart cherries are at full bloom.  Bloom is variable with a heavy bloom at some sites and a lighter bloom in others.  Leaves are emerging and growers should prepare for cherry leaf spot.

In Plums, European plums are at petal fall.  Oriental plums are in the shuck.  Growers should apply fungicides to reduce black knot in plums as shoot growth begins.

Apples are near full bloom in most varieties.  There have been widespread apple scab infection events this spring and scab spores are caught in good numbers during the rains.  Apple scab symptoms have been found in unsprayed trees.  Many more symptoms from recent scab infections should show up next week.  A new model for fireblight on the Enviroweather website allows growers to easily track the disease.  The cool conditions forecast for the next few days will suppress bacterial growth and lower the risk of fire blight.  Fire blight infections are more likely to develop later in bloom when warm rains occur.  Growers with Streptomycin resistant bacteria will want to use Kasumin (Kasugamyacin).  Under the requirements of the Section 18 permit, this material cannot be the first bloom material used to control fire blight.  Kasumin cannot be used unless the regional fruit Code-A-Phones (269-657-8317 or 269-944-1477 x 805) indicate a significant fire blight risk.  There is little insect activity to report.  Spotted tentiform leafminer adults are flying and laying eggs.  European red mite eggs have hatched.  Oriental fruit moth are flying in good numbers.  

Pears are at full bloom.  Pear scab is a concern with infection conditions similar to apple scab.  Pear growers can use the apple scab model at the enviroweather site to track pear scab.  Pear Psylla eggs and nymphs are hard to find.

Small fruit

Blueberries are at pink bud and bloom is beginning in early varieties.  Winter injury of fruit buds in several varieties can be found in a few areas but other areas show little damage. Cold injured buds show little growth or reduced flower numbers.  Many fields have standing water and are rutted from spray tractors.  Aircraft were used to apply mummyberry sprays last week.  Growers should focus fungicide applications on mummyberry.  Shoots are about one inch long and leaves are unfolding so the young shoots are very susceptible to infection if we get any prolonged wetting or freezes.  The Michigan Blueberry IPM Newsletter is posted at the MSU Blueberry IPM web site .  The first Blueberry IPM Update meeting is planned for 6 – 8 PM on May 13 at the Bodtke Farm at 01240 57^th Street, west of Grand Junction MI.

Grape buds are at bud burst.  In juice grapes the crop looks good.  Winter damage is apparent in my wine grape vineyards but it does not seem severe in many orchards.  Growers should apply fungicides to reduce phomopsis as the first leaves unfold and especially as the flower clusters are exposed when the shoots are about 3 inches long.  See the most recent copy of Grape IPM Newsletter at the MSU Grape current conditions webpage.  Here is a link a table of SW Michigan’s Growing Degree-Days from April 1 to May 2, 2009. 

Strawberry bloom has started across the region. 

Raspberry shoots are elongating and more leaves are out.  Winter injury is apparent in brambles especially blackberries which were hit hard in some areas.

Cranberries have not yet  begun to green up.

Miscellaneous

Paw Paws and walnuts are blooming.

Growers are planting trees and applying fungicides.

The Fruit Code-A-Phones in Van Buren County (269) 657-8217 and Berrien County (269) 944-4126 ext 1 are being updated. The next Monday Fruit IPM Update meeting will be, Monday May 11, at the Fruit Acres Farm in Berrien County.