SW Michigan Fruit Update
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Southwest Michigan, September 1, 2009

Mark Longstroth, Bill Shane, Diane Brown-Rytlewski

Weather

Last week was cool with highs falling from the 80s into the 60s and lows in the high 40s.  Rain midweek brought 1.5 to over 2 inches of water such that most sites have good moisture content.  We continue to lag about 8 days behind normal in heat units accumulated but only slightly later than last year.  Apple development is moving along fairly rapidly in spite of recent cool weather.  The SW Michigan apple maturity report is being posted weekly on Wednesdays from now through early October at the SW Michigan Research and Extension Center web site fruit newsletters.

 

Southwest Michigan Growing Degree Day Totals March 1 through August 31, 2009				Grapes, April 1
Location	GDD 42	GDD 45	GDD 50	GDD 50
SWMREC:	3180	2740	2051	2015
Fennville:	2960	2531	1857	1832

You can find weather and IPM information for Southwest Michigan at the Enviroweather website. 

Insects

Japanese beetle numbers are decreasing.   

Tree fruit

Peach, Harvesting Cresthaven, PF25, Loring, Glowingstar, PF19-007, PF23, PF24-007, PF24C, Allstar, Blushing Star, Redkist, and Baby Gold. Quality continues to be good with relatively few split pits.  Summer pruning is needed to increase red color of skin for older varieties such as Redskin.  Brown rot is common in some orchards and fungicide treatments for brown rot are needed as fruit color.  Tarnished plant bug and stinkbugs are common in orchards with broadleaf weeds. 

In Plums,Stanley harvest is complete, with harvest of NY9, Italian, and Vision underway. Ripening plums should also be protected from brown rot.  Apple maggot is a problem in ripening plums.  Scout for leafhopper damage from white apple or potato leafhoppers. 

Apple harvests of Gingergold, Williams Pride, Zestar, Pristine, Mollies Delicious, and Jonamac is underway.  A few Macs and Gala are being spot picked. Empires and Jonathans are being harvested for caramel apples. Pinpoint scab being reported on fruit. Sunscald-like symptoms are appearing on Gala.  Sooty blotch and flyspeck is still relatively rare.  Codling moth trap catches have declined for most orchards and Oriental fruit moth trap catches have been climbing.  Young larvae of either oriental fruit moth or codling moth are being seen in some orchards.  Apple maggot flies are in good numbers following the rain.  Obliquebanded leafrollertrap catches are still up. 

In Pears,Bartlett harvest continues with some Anjou and Bosc being picked.  Harrow Sweet harvest is expected next week, depending on the site and the market.   Growers should protect against the second generation of codling moth, which attacks pears just before harvest.  Pear scab, Fabraea leafspot and sooty blotch are the primary diseases of concern.

Small fruit

Blueberry harvest is nearly done, with some growers stopping this week.   Blueberry maggot and alternaria fruit rot are the primary problems of concern. For more information look at the Michigan Blueberry IPM Newsletter posted by Paul Jenkins at the Berry Entomology Lab. 

In Grapes, harvest of Mars, Fredonia, Himrod are underway with Marquis to follow.  The diseases of greatest concern now are botrytis and downy mildew.  Wet conditions spread botrytis, so susceptible varieties should be protected at veraison and whenever soaking rains are conducive to the disease.  Morning dews are good for the spread of downy mildew, so fungicides against downy mildew are required during the summer season when there are morning dews.  The third generation of grape berry moth is flying, eggs are hatching and stings and tunnels can be found on the fruit.  Japanese beetles numbers are up following this weekend’s rain.  See the most recent copy of Grape IPM Newsletter at the MSU Grape current conditions webpage.