SW Michigan Fruit Update

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Southwest Michigan Fruit Report,
September 2, 2008

Mark Longstroth, Bill Shane

Apple maturity reports from SW Michigan and other Michigan regions begin this 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 SW regional reports by email contact Bill Shane. 

The last fruit report will be September 17.

Weather

Temperatures were moderate during the past week similar to the week before.  Highs have been in the mid to upper 70s and lows near 50 with a light rain last Friday at the southern end of Berrien County.   Soils remain dry with southern areas as much as 5 inches below normal for the year. Plants in sandy sites are showing poor color and nutrient deficiency symptoms.

Southwest Michigan Growing Degree Day Totals March 1 through August 31, 2008				Grapes, April 1
Location	GDD 42	GDD 45	GDD 50	GDD 50
Berrien Springs:	3348	2920	2252	2252
Scottdale:	3281	2858	2203	2195
SWMREC:	3229	2810	2159	2153
Bainbridge:	3215	2796	2150	2144
Hartford:	3089	2673	2033	2029
Lawton:	3340	2910	2238	2233
Grand Junction:	3380	2951	2288	2281
South Haven:	3105	2693	2052	2049
Fennville:	3040	2628	1990	1986

Tree fruit

Young trees should be irrigated to reduce drought stress.  San Jose scale male moth catch has declined but crawlers are still emerging and can cause fruit damage.  Growers should note where fruit are showing scale damage so that control strategies for next year can be planned.  Codling moth and Oriental fruit moth are still flying in significant numbers in many area orchards.  Trevor Nichols research station in Fennville is still catching significant numbers of Japanese beetle adults although activity in the lower SW region has dropped off considerably. 

Peach harvest includes PF23, Cresthaven, Redskin and Glowingstar.  Fruit color and quality continues to be very good although fruit size is suffering in some sandy sites due to lack of rain.  Bacterial spot symptoms on fruit are widespread but generally not severe except on a few very susceptible varieties. Brown rot is only a minor problem in the area.  Oriental fruit moth entries into fruit can be found occasionally.  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.  Post harvest pruning should be completed soon.

Plum varieties being harvested include Simka, Castleton,and NY6 with Stanleys starting in a few weeks.  Brown rot incidence is generally low.  Growers should scout for apple maggot, white apple and potato leafhoppers. 

Harvest of Gala and Golden Supreme Apples are underway.  Harvest of Empires for taffy apples is continuing.  Jonagold apples in orchards with light crops, although not fully mature, are being picked now before they become too large for the processing equipment.   Many varieties such as Empire, Golden Supreme, and Honeycrisp are showing sunscald symptoms.  Trap catch for codling moth has been essentially continuous since mid June for several orchards with relatively high population levels. Unlike codling moth, oriental fruit moth larvae tend to enter fruit at the stem or calyx ends.  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 range from ¼ to ¾ inch and are targeting fruit now.  Green apple aphids are leaving apple orchards as new terminal growth ceases.   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 male trap catch has been declining since early August however crawlers are still emerging out causing red spots on apple fruit is showing up.  Young trees should be irrigated and examined for potato leafhopper.

In Pears, Bartlett harvest is underway.  Quality is good although size is down slightly.  Both codling moth and oriental fruit moth can damage pear fruit at this time. 

Small fruit

Blueberry harvest is winding down with Elliot 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.  A wide range of fruit maturities are present in both juice and fresh type vineyards that were damaged by frost.  Vineyards that have historically had high grape berry moth pressure should be treated.  Phomopsis berry rots are showing up.  With frequent heavy dews we expect downy mildew to increase.  Fungicides at this time should target downy mildew.  Botrytis fruit rot has been found in wine grapes.

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

Fall Raspberry harvest is underway.  We are now receiving heavy dews every morning so growers should protect against botrytis or gray mold in ripening fall fruit. Dry conditions have made irrigation important for getting good fruit size.