SW Michigan Fruit Update

Check the Index for earlier postings

June 13, 2006

Bill Shane, Mark Longstroth

Weather

Last week was pleasant.  Highs were in the 70s and lows in the 50s.  Scattered rain fell Tuesday and Wednesday.  Rainfall totals ranged from a third to two inches.  Topsoils have barely adequate to adequate moisture.  Soil temps are in the 70s.  This week’s forecast is for warm weather with highs in the 70s and chance of thunderstorms, with a warm weekend.  The GDD below are from the Enviroweather site.

Southwest Michigan Growing Degree Day Totals March 1 through June 11, 2006				Grapes, from April 1
Location	GDD 42	GDD 45	GDD 50	GDD 50
Scottdale:	1170	964	669	639
SWMREC:	1139	924	624	592
Bainbridge:	1198	979	672	638
Hartford:	1056	854	574	547
Lawton	1213	997	692	677
South Haven (April 1)	899	733	496	496
Grand Junction:	1200	986	688	651
Fennville:	1044	839	560	532

Tree fruit

Plum curculio and tarnished plant bug activity continues but less than a week ago.  Rose Chafer are out but generally not in large numbers. 

Apricot fruit are 2 inches in diameter. 

Peach fruit are 1.5 inches.  Oriental fruit moth larvae (up to 0.3” in length) are being found in peach fruit.  We are at the end of the first generation flight.  Tarnished plant bug damage and rusty spot (powdery mildew) can be found affecting peach fruit.  Bacterial spot has been reported in some locations but is generally minor. 

Sweet cherries are showing color and harvest of early varieties should begin soon.  Plum curculio egg laying has been underway for some time.  Leaf spotting due to bacterial canker due to cool wet conditions some weeks ago is the most common leaf disorder.

Tart cherries are turning yellow and growers will be applying Ethrel soon. Ethrel should not be applied before all the fruit in an orchard have changed to yellow.  Growers need to protect against plum curculio and cherry leaf spot.  Very little cherry leaf spot symptoms have been found yet.  Leaf yellowing, black spots and shot holing of the leaves from bacterial canker are fairly common.  Fruit symptoms of bacterial canker can also be found but are less common. 

Plumsare at 18 mm fruit and pit hardening has begun?  The crop looks light to decent depending on the site and variety.  Growers need to protect against plum curculio and to maintain protection for black knot.  White apple leafhoppers are causing stippling of the leaves.

Apple fruit are over an inch in diameter.  Fruit drop continues.  Primary apple scab is over but scab symptoms are appearing in some orchards.  Growers need to maintain scab protection if they find leaf lesions in their orchards.  Growers should protect against powdery mildew.  Fire blight symptoms and bacterial ooze are not common but trauma blight could be a problem if we get severe weather in orchards with oozing shoots.  Oriental fruit moth and codling moths trap counts are up.  A regional biofix for codling moth occurred on Thursday May 25.  Codling moth Biofix at SWMREC was at 328 GDD base 50.  Cover sprays for codling moth egg hatch should have been applied at 100 to 250 DD past this point, depending on the insecticide used.  You can monitor the GDD model for these pests at the Enviroweather site.  See the article on pesticides for codling moth in the Fruit CAT Alert.  Obliquebanded leafroller are being caught in the area.  Other regions are report high numbers of European red mites in some areas so growers should scout their hot spots.  New red mite eggs are being seen.

Pear fruit are about an inch in diameter.

Small fruit

Blueberry fruit are growing rapidly.  Protection against anthracnose fruit rot should be the main disease concern now.  Cherry fruitworm and cranberry fruitworm are being caught in pheromone traps.  See the article on these fruitworms in the Fruit CAT Alert.  Typical time to treat these pests is at the end of bloom.  Post bloom sprays also control blueberry gall midge and blueberry tip borer.

In Grapes, Concord bloom on primary shoots started on June 7 and we are at full bloom.  Secondary and tertiary shoots are 12 to 18 inches long.  Rose Chafers are feeding in some vineyards.  This pest may require treatment if they are in vineyards you plan to harvest.  Phomopsis leaf lesions are common in most plantings.

Strawberry harvest is underway across the region.  Fruit quality has generally been good due to relatively dry and moderate temperature conditions.  Irrigation is important for good fruit size.

Raspberry and blackberry bloom is underway.  Growers should be scouting for leafrollers.

Cranberry bloom has begun at the edges of beds. Now is the time for prebloom fungicide sprays.

Miscellaneous

The next Monday Fruit Update meeting will be Monday June 19, at the Fruit Acres Farm in Berrien County, at 5 PM.