SW Michigan Fruit Update

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Southwest Michigan Fruit Update, June 4, 2007

Mark Longstroth, Bill Shane, Greg Vlaming

Weather

Last week was hot.  Highs were in the 80s and lows in the 60s.  With moist soils all crops made good growth.  A cold front moved through the region on Saturday June 2, with a rain Sunday and Monday.  Precipitation totals were about 0.5 to 1.5 inches of water, with less rain falling close to the lake.  A long wetting period of 40 to 50 hours at about 65F was a major infection period for all fruit diseases.  The forecast is for cooler weather with showers and temperatures in the 70s are forecast this week.

Southwest Michigan Growing Degree Days (GDD) Totals March 1 through June 3, 2007				Grapes from April 1
Location	GDD 42	GDD 45	GDD 50	GDD 50
Scottdale	1216	1024	744	637
SWMREC:	1171	980	708	610
Bainbridge:	1151	966	697	596
Hartford:	1118	935	669	574
Lawton	1268	1074	786	649
Grand Junction:	1223	1033	750	621
South Haven	1084	904	648	555
Fennville:	1048	867	608	528

Insects

Only a few Rose Chafers have emerged.  Potato leafhoppers are easier to find.  Plum curculio damage is common, but we expect that most of the damage from this generation. 

Tree fruit

Peach fruit are 20-25 mm in diameter and small fruit are dropping.  We are not yet at pit hardening.  We are finding Oriental fruit moth larvae feeding in the fruit.  Oriental Fruit Moth trap catch is low.  Flight of the first generation has ended and the second generation of Oriental fruit moths should be emerging soon so pheromones traps should be renewed.  Growers should protect susceptible varieties from peach mildew or rusty spot.  Rust spot symptoms have been reported.

Tart cherries moved quickly in the warm weather and fruit are yellowing.  Growers should not apply ethephon until all the fruit on a tree or in an orchard has changed color to yellow.  Maintain protection for plum curculio and cherry leaf spot.  Cherry leaf spot symptoms are appearing in many tart cherry orchards.  Now is the time to put out cherry fruit fly traps.

Sweet cherries are straw colored and early varieties are coloring.  We had a significant drop of aborted and injured fruit last week.  Growers need to protect against plum curculio and brown rot.  Now is the time to put out cherry fruit fly traps.

Plum fruit are about 18 mm in diameter.  Growers should be protecting against plum curculio black knot and brown rot. 

Apple fruits are ¾ to 1 ¼ inches in diameter.  We had a heavy drop and the fruit set looks good in most orchards.  Fire blight symptoms are becoming common.  The weekend rain probably removed almost all the primary scab spores.  Growers should check their orchards for scab lesions on the leaves and determine if they should maintain fungicide protection.  The waxy fruit is not very susceptible to scab infection at this time but young leaves are very susceptible. Codling moths were biofixed on Wednesday, May 9 (325 GDD50 at SWMREC).  We are past the peak of egg laying.  We are catching Obilquebanded leafrollers.  Biofix was last week at 950 GDD base 42.  Treatment is timed for 450 GDD after biofix at peak egg laying.  The second generation of Oriental fruit moths should be emerging soon and pheromones should be renewed in traps.  European red mites are scarce and were probably reduced by the heavy rains. Rosy apple aphids are curling leaves and green apple aphids are feeding on shoot tips.  Growers may want to treat young nonbearing trees to control potato leafhopper.

Pear fruit are 25 mm in diameter.  Pear rust mites are browning leaves in unsprayed trees.  

Small fruit

Blueberries have green fruit.  Shoot growth has stopped, but many shoots have begun a new flush of growth.  Cranberry fruitworm are still flying and fruit worms can be found feeding in the fruit.  Growers should apply fungicides to reduce anthracnose fruit rot later.  Be sure to check the new Blueberry IPM Newsletter at the MSU Blueberry Site. 

Grapes: Concord bloom is ending.  Vinifera bloom is just beginning.  The rain over the weekend was an infection event for grape diseases.  Growers who did not have materials on for the June 2-3 rain should consider materials with back action.    Phomopsis lesions were found on grape leaves and shoots.  Treatments for grape berry moth should be timed soon.  We expect to see rose chaffer soon.  Check the MSU Grape website for scouting updates.

Strawberry harvest from matted rows has begun.  The fruit ripened rapidly in last weeks heat.  Growers may want to treat young plantings to control potato leafhopper.

Raspberries: Summer raspberry have green fruit and the crop looks good. 

Cranberry shoots are elongating and flower buds are emerging.

Upcoming Meetings

There is a statewide preharvest strawberry meeting this Thursday June 7.

The next Monday Fruit Update meeting will be Monday June 11, 5 PM, at the Fruit Acres Farm in Berrien County.  There are RUP credits available for the Monday Fruit Update meetings.

There is a Blueberry IPM meeting on Wednesday June 13 at 10 AM to Noon at Bodtke’s Main Farm on 01240 57th Street, north of Phoenix Road east of Grand Junction.  This meeting will review scouting of blueberry fields; weed, insect and disease control in the mid season before harvest. There are RUP credits available for these two Blueberry meetings.

A series of twilight grape scouting IPM meeting will start next week. The dates and locations are; June 14 at Tim Seppala's farm, east of Lawton; July 12 at Bob Dongvillo's farm, south of Scottdale; and August 19 at Lemon Creek Vineyards, west of Berrien Springs. These meetings start at 6 PM.  For more information on these meetings call Mark Longstroth at (269) 675-8313.