SW Michigan Fruit Update

Check the Index for earlier postings

Southwest Michigan, August 25, 2008

Mark Longstroth, Bill Shane

Apple maturity reports will begin next week.  They are available by email or by going to www.maes.msu.edu/swmrec.  Look under publications for fruit reports.  If you are interested in receiving the reports by email contact Bill Shane. 

Weather

Cooler weather this past week.  Highs have been in the mid to upper 70s and lows near 50.  Last Friday, a storm system moved through the region and left about a half inch of rain in most areas.  Soils remain dry.  Annual plants and field crops are wilting due to water stress and trees are beginning to shed leaves.  The forecast for the upcoming weeks is for continued cooler and dryer than normal conditions indicating that the lack of water will continue.  The Growing Degrees below have been corrected for some missing data at sites marked with an asterisk*.

Southwest Michigan Growing Degree Day Totals March 1 through August 24, 2008				Grapes, April 1
Location	GDD 42	GDD 45	GDD 50	GDD 50
Berrien Springs:	3176	2764	2130	2120
Scottdale: *	3179	2768	2133	2125
SWMREC: *	3084	2669	2035	2041
Bainbridge:	3044	2645	2033	2026
Hartford:	2912	2517	1911	1907
Lawton:	3152	2744	2106	2101
Grand Junction:	3196	2789	2159	2153
South Haven:	2927	2536	1929	1922
Fennville: *	2911	2514	1900	1896

Tree fruit

Young trees should be irrigated to reduce drought stress.  San Jose scale crawlers are out and can cause fruit damage.  We are seeing this pest in more orchards this year.  Codling moth and Oriental fruit moth are flying.  Few Japanese beetles have been out recently. 

Peach harvest continues with PF23, Allstar and Beaumont harvest.  Fruit size of later ripening peaches starting to suffer.  Brown rot is still a problem.  The third generation of Oriental fruit moth is flying. 

In Cherries, leaf yellowing and drop from cherry leaf spot continues, but drought stress will also cause leaf drop.

Plum varieties being harvested range from Shiro and Ozark Premier.  Stanley fruit and leaves showing a fair amount of bacterial canker symptoms from earlier cool and wet weather.  Growers should scout for apple maggot, white apple and potato leafhoppers. 

Apples harvest is underway.  Growers are finishing Paulared and color picking Gala and McIntosh.  General harvest of Gala will begin next week.  Trap catch for codling moth is down but still high indicating the second-generation flight.  Codling moth entries are easy to see, especially on yellow skinned varieties.  It is doubtful that there will be a third generation this year.  Few Apple maggots have been caught for several weeks in SW Michigan.  Apple maggot emerges following rain, about ¼ of an inch is considered the trigger amount.  This means that growers can expect an increased emergence following rain.  Obliquebanded leafroller larvae are easier to find feeding on leaves.  With very little leafroller feeding on apple fruit.  Spotted tentiform leafminer mines can be found.  The new insecticides Delegate and Altacor seem to be doing a good job controlling this insect.  Green apple aphids are common in growing shoot tips.   White apple leafhopper leaf stippling and bronzing due to European red mites are generally scarce.  Growers should inspect calyx ends of apples for mite eggs.  San Jose scale crawlers are out and red spots on apple fruit is showing up.  Young trees should be irrigated and examined for potato leafhopper.

In Pears, Bartlett harvest is underway.  Both codling moth and oriental fruit moth can damage pear fruit at this time. 

Small fruit

Blueberry harvest continues.  Elliot is the variety being harvested now.  Anthracnose ripe rot, small fruit and soft fruit have been a problem.  Leaf spots are a problem is some areas.  Drought stress is revealing other mineral nutrition problems such as iron and potash.  Japanese beetles and blueberry maggot flies are out. 

Grapes are in veraison.  Concord vineyards that were damaged by frost still have a lot of green berries while other vineyards where most of the bloom was on primary buds have finished verason.  Grape berry moth trap catches are variable.  Vineyards that have historically had high grape berry moth pressure should be treated.  Fungicides at this time should target downy mildew.  Phomopsis berry rots are showing up.  With frequent heavy dews we expect downy mildew to increase.  Botrytis fruit rot has been found in wine grapes.

Strawberries should be protected against potato leafhoppers to prevent stunted growth.  Irrigation is very important do get good growth during this dry season.

Fall Raspberryharvest is underway.  We are now receiving heavy dews every morning so growers should protect against botrytis or gray mold in ripening fall fruit.