SW Michigan Fruit Update

Check the Index for earlier postings

September 5, 2006

Mark Longstroth, Bill Shane

Weather

For the last few weeks, highs have been in the low 80s to the 70s.  Rain with hail moved across the region Wednesday, August 23.  Severe damage was reported in blueberries where fruit and leaves were knocked off the bushes and the bark of stems was torn.  Apple fruit was also damaged reducing the crop to juice grade fruit.  Rainfall totals were as high as four inches in the south.  Most areas received about two to three inches or more in the last two weeks.  This week’s forecast is for warm weather with highs in the 70s with a chance of thunderstorms almost every day. In the last week we picked up 200 GDD base 42 and 100 base 50.  In the coming week we will pick up about 200 GDD base 42 and 100 base 50.  The GDD below are from the Enviroweather site.

Southwest Michigan Growing Degree Day Totals March 1 through September 3, 2006				Grapes, from April 1
Location	GDD 42	GDD 45	GDD 50	GDD 50
SWMREC:	3564	3109	2401	2364
Lawton	3705	3235	2506	2491
Fennville:	3405	2958	2266	2236

General Insect Activity

Japanese beetles numbers are low.  Apple maggot flies are down.  Trap catches for both oriental fruit moth and codling moth are variable with high numbers reported in some locations.  You can use the Enviroweather site GDD model for some pests if you know its emergence or Biofix at your site.

Tree fruit

Peach harvest is declining.  Varieties being harvested include Encore and other late varieties.  We are at the end of the third generation of oriental fruit moth.  Brown rot continues to be a problem for some growers. 

Sweet cherry and tart cherry orchards generally look good.  Some tart cherry orchards have been defoliated by cherry leaf spot.

In Plums, Stanley harvest has begun.  Brown rot is problem for some growers. 

In Apples, Gala and McIntosh harvest have begun.  Hail damage was widespread but variable in Van Buren County. Apple maggot trap catches have declined.  Trap catches for oriental fruit moth and codling moth vary quite a bit in area orchards.  We should be at the end of the third generation of oriental fruit moth.  And the second generation of codling moth, but trap numbers are up in some orchards.  Growers with late and mid season apples may want to apply one last cover spray if they are unsure of their trap numbers in orchards.  Sooty blotch and flyspeck is appearing in some sprayed orchards.  Some apple growers have reported pinpoint apple scab.

Pear harvest has begun.  Bartlett pears are being harvested.

Small fruit

Blueberry harvest continues.  Elliot harvest is underway.  Hail, August 23, in Allegan and Van Buren counties caused the loss of crop in many Elliot and Jersey fields.  Since Elliot harvest had just begun this is a significant loss to those growers.  Some harvest of the remaining fruit has shifted to berries for processing.   

In Grapes, Niagara harvest should start next week, September 12.  Grape berry moth trap catch numbers are down.  The heavy dews each morning are excellent conditions for downy mildew; this disease is widespread and common.  Grape scouting reports can be found at the MSU Grape recourses page at www.grapes.msu.edu.

Strawberry new growth is off to a good start.  Potato leafhopper burn and leaf spot are common in many fields.

Fall Raspberry harvest is underway with large volumes of fruit in local markets.  Heavy morning dews are common and this increases the likelihood of gray mold.  Monitor pre harvest intervals (PHI) for fungicide and insecticide sprays.