SW Michigan Fruit Update

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Southwest Michigan Fruit Update, August 7, 2007

Mark Longstroth, Bill Shane, Greg Vlaming

Weather

The last two weeks have been hot and dry.  Highs have been in the 80s with lows in the 60s.  Rain fell across the region Sunday, August 5.  Rainfall totals were higher in the southern tier of counties and closer to the lake.  Berrien County received about 3.5 to 2.5 inches of rain.  Less rain fell away from the lake and to the north.  Most areas in Van Buren County received 1.5 to 0.7 inches.  The topsoil now has moisture but the subsoil is still dry.  The forecast is for hot weather with thunderstorms. 

Southwest Michigan Growing Degree Days (GDD) Totals March 1 through August 5, 2007				Grapes from April 1
Location	GDD 42	GDD 45	GDD 50	GDD 50
Scottdale	3065	2684	2092	1985
SWMREC:	2965	2587	2002	1904
Bainbridge:	2881	2509	1932	1901
Hartford:	2780	2409	1836	1741
Lawton	3039	2627	2039	1962
South Haven	2777	2389	1810	1827
Fennville:	2739	2370	1802	1722

Insects

Japanese beetle adults are still actively feeding and we expect more following this rain.

Tree fruit

Fruit crops continue to show signs of drought stress such as sunscald of the fruit and leaf drop.  The dry conditions this season have resulted in very little disease pressure in most fruits.

Peach growers are harvesting Coralstar and PF17 peaches.  Color has been good.  Because of high demand, peaches are being harvested with few pickings (2 to 3 picks instead of a more typical 3 to 4 picks).  There is thrip damage to the fruit in some orchards.  The third generation of oriental fruit moth should emerge at about 2400 GDD base 45.

Cherry trees are dropping leaves due to drought stress.  Only a little cherry leaf spot has occurred so far but this rain should result in an increase in disease symptoms.  Because there has been so few infection periods so far it will take a long time for disease pressure to build and cherry trees should enter the winter in good shape.

In Apples, Codling moth trap catches of the second generation have been heavy.  Biofix for high-pressure sites was July 14^th (~1275 GDD) and lower pressure site biofix was approximately July 21^st (1674GDD).  Areas that have had earlier flights and biofixes for second-generation codling moth may see a partial third generation in late August.  With wide spread rain I expect apple maggot to emerge around the edges of fields so border sprays will be useful in some areas.  We are finding feeding damage of second-generation oriental fruit moth in apple fruit.  Scouts are reporting leaf drop due to the second generation spotted tentiform leaf miner.  Dock sawfly larvae are feeding on broadleaf weeds in some orchards.  This pest is often confused with codling moth in apples later in the season as it looks for an overwintering site and attacks the fruit.  With this rain, fungicides should be included in cover sprays to control sooty blotch and fly speck.  Cork spot is showing up on early apple varieties.  Paulared harvest is beginning and Gala harvest is projected to begin about August 24^th.  Retain applications should go on approximately 4 weeks before anticipated harvest to control pre-harvest drop and to delay fruit maturity.  NAA timing for controlling pre-harvest drop is about 7-10 days before anticipated harvest.

Pear fruit needs to be protected from the second generation of codling moth.  European red mites do not bronze the leaves of pears but turn them black.

Small fruit

Blueberry harvest continues.  Currently we are finishing Bluecrop, second or third picking of Jersey and Elliot harvest is in full swing.  Growers are irrigating to maintain fruit size.  Sprinkler irrigation is conducive to fruit rot development and fungicide protection is very important in these fields. Anthracnose and Alternaria can be found.  With wide spread rain I expect blueberry maggot to emerge around the edges of fields so border sprays will be useful in some areas.  Japanese beetles and blueberry aphids are out.  Be sure to check the new Blueberry IPM Newsletter at the MSU Blueberry Site. 

Grape veraison has begun in early ripening varieties such as Foch, Reliance, and Himrod.  Grape berry moth trap catch numbers are up.  The second-generation flight is underway and egg laying is underway.  Japanese beetle and grape leafhopper numbers are building.  Backyard growers are reporting heavy losses to black rot.  By now the berries on most varieties are resistant to grape diseases.  Phomopsis berry rot and drop has begun on early ripening varieties.  A botrytis bunch rot spray is timed for veraison in wine and table varieties. The final grape IPM scouting meeting will be Thursday, August 9, at Lemon Creek Vineyards, west of Berrien Springs at 6 PM.  Check the MSU Grape website for scouting updates.

Strawberry growth is good where irrigation has been used and potato leafhopper controlled; Otherwise strawberries have suffered from the drought. 

Raspberry cane borers are attacking primocane shoot tips.  Remove the girdled section at the base of the wilted shoot tip and destroy.  This girdled section contains the raspberry bane borer egg. 

Plum Pox Update

Plum Pox sampling in SW Michigan is progressing well.  All orchards located within 5 miles of last years positive find as well as farms from across Berrien, Van Buren and Allegan County are being sampled in SW Michigan this summer. Sampling will continue through Mid August.  The MDA sampling teams have collected over 40,000 SW MI samples and all results reported out of the labs have been negative in 2007.

Meetings

The final grape grower IPM meeting is this Thursday at Lemon Creek winery 6-8pm.  This is the last grape IPM meeting of the year don't miss it! Grape growers can learn more about prevention of harvest-time diseases and insects such as powdery mildew, botrytis, grape berry moth, yellow jackets and Asian ladybeetles. Demonstrations of scouting techniques will help growers learn how to check their own vineyards for these pests and the latest control options.

Lemon Creek Winery (http://www.lemoncreekwinery.com) is on East Lemon Creek Road between Lauer and Hollywood Roads in Berrien Springs, on the south side of the road. The meeting will start at 6 pm with a free cookout dinner, followed by the educational program. For more information, please call Steve Van Timmeren at (517) 242-1282.