SW Michigan Fruit Update

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August 23, 2005

Mark Longstroth
Bill Shane
Al Gaus

Weather

Last week’s weather was warm and dry with highs falling from the upper 80s to the mid 70s and lows in the 60s. There was rain last Wednesday and Saturday. Total precipitation amounts varied from a third of an inch to almost 2 inches.  This week’s forecast is for cooler weather with a chance for rain near the weekend. 

Southwest Michigan Growing Degree Day Totals  March 1 through August 21, 2005				Grapes April 1
Location	GDD 42	GDD 45	GDD 50	GDD 50
SWMREC:	3364	2962	2336	2314
Bainbridge:	3425	3018	2384	2361
Hartford:	3155	2759	2140	2121
Grand Junction:	3413	3011	2382	2358
Fennville:	3183	2791	2179	2151

Tree fruit

Trap catches were up for the last two weeks, following low trap catches the first week of August.  Trap catches are also very variable from site to site.  We are still catching apple maggot and blueberry maggot.  Japanese Beetles numbers are declining.  Mite numbers are still high in many crops. The second generation of Codling moth and the third generation of Oriental fruit moth are ending, but we expect these pests to return soon. Leafroller larvae are still a problem and obliquebanded leafroller and redbanded leafroller trap catches are up.

Peach harvest continues with Loring and Glowing Star. Oriental fruit moth trap catches are high and the third generation is flying. We set Biofix as July 27 at 2259 GDD base 45 at SWMREC and egg hatch will continue to about 3200 GDD base 45. Brown rot is showing up here and there. Several growers have reported San Jose scale

Cherries look good.  There is still little sign of cherry leaf spot. Mites have caused bronzing in many orchards.

Early Plum harvest has begun. Stanley Plums are coloring.  Growers should protect against brown rot.

In Apples, we are harvesting Paula Red, Ginger Gold for the fresh market and early Mac types for processing.  Gala and Jonathan harvest will begin next week in some orchards. 
I am looking for orchards that have sooty blotch and flyspeck in them. A researcher in Iowa wants to collect samples from light skinned varieties from Michigan to do genetic testing to determine what species of these diseases we have here. She will take the samples and will pay for the fruit. Sooty blotch and flyspeck cover the fruit in abandoned orchards at this time. This researcher is looking to recover discrete colonies for her study. If you have sooty blotch in your orchard and would be willing to part with a few dozen apples please let me know. Mark Longstroth
We caught fewer apple maggots last week. We biofixed on codling moth July 20, at 1581 GDD base 50, we are now at 2336 GDD. I expect the second generation to end about 2330 GDD base 50 and I also expect a third generation of codling moth to beginning flying soon, see the articles in this weeks Fruit CAT Alert. Trap catch for Obliquebanded leafroller was up last week indicating the overwintering generation is out. I set biofix for this generation as Friday August 12 at 3100 GDD base 42s.  Redbanded Leafroller flight is up.  Leafroller larvae are common. Oriental fruit moth trap catches are down indicating the flight of the third generation is tapering offs. Growers need to protect against Oriental fruit moth and codling moth for several more weeks. Many growers have applied treatments for European red mite. If you have seven mites per leaf you should control European red mite.  White apple leafhopper nymphs are easy to find. Examine 50 leaves from 10 different trees and treat if the average is more than one nymph per leaf.

Pear harvest has begun.

Small fruit

Blueberry: Most growers have finished harvest. Elliot harvest is ending. In many fields harvest ended early due to poor fruit size and quality. Fruit quality for harvests after the first picking was poor and size was small.  Mechanical harvesters complained that the fruit did not come off the bush easily.  Blueberry maggot and Japanese Beetles are still out.  Tussock moth larvae are a problem in some areas.  Phomopsis was a problem in some areas.

Grape veraison is almost complete. Grape berry moth egg hatch increased sharply last week with the beginning of the third generation flight. Insecticide sprays to control egg hatch should be applied. See the article in the July 26 Fruit CAT alert on “Controlling mid-season grape berry moth.” Disease pressure this dry summer has been light and there is little need for fungicides mixed with the insecticides needed to control Grape berry moth.

Strawberry growers should protect against leaf diseases and potato leafhopper.

Fall Raspberry harvest is continues. With heavy dews every night growers need to protect against fruit rots especially gray mold and botrytis.