SW Michigan Fruit Update

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Southwest Michigan, April 9, 2007

Mark Longstroth, Bill Shane, Greg Vlaming

Weather

Temperatures in the end of March were seasonal. The beginning of April was warm with record high temperatures on Tuesday April 4 but frigid weather arrived on Wednesday with snow and highs near freezing for the next four days. Lows near 20 occurred on Friday and Saturday mornings.  Low temperatures were a few degrees higher close to Lake Michigan and the extreme cold did not last as long.  Plant development was rapid at the end of March and many fruit crops were damaged by the freeze.  We only a few GDD behind 2000 and 1996, other early warm years.  The current forecast for the week is for temperatures near freezing with rain or snow likely and cloudy conditions.  Most of the snow has melted and water is standing in poorly drained sites.  We did have a radiation freeze Tuesday morning with lows in the low 20s

Southwest Michigan Growing Degree Day Totals March 1 through April 8, 2007				Grapes, from April 1
Location	GDD 42	GDD 45	GDD 50	GDD 50
Scottdale	247	194	125	18
SWMREC:	233	182	116	18
Bainbridge:	237	187	119	18
Hartford:	226	177	113	18
Lawton	265	214	144	24
Grand Junction:	253	202	132	20
South Haven	220	171	108	15
Fennville:	199	153	94	14

Tree fruit

Little insect activity was noticed due to the freezing cold temperatures.  Exposed green leaf tissues appear brown, black or watersoaked are obviously damaged from the freeze.  Because of the long duration of the cold temperatures we are not sure if there will be affects due damage to the shoots and leaves.  Warmer temperatures will make it easier to determine the extent of the injury.  This frost was very variable and we will be looking at damage and determining the extent of damage for several more days.  Many exposed sites show more damage than is typical.

Apricots were blooming and suffered severe damage from the freeze.

Peaches were showing first pink and bloom had begun in Berrien County.  Open flowers were killed by the freeze but closed flower are still viable.  A good crop of peaches is still possible in Berrien County but further away from the lake all the peach flowers were killed.

Tart cherriesare at green tip to bud burst. Growers report heavy losses in Allegan and Van Buren counties.  The tart cherry crop looks better in Berrien County.  It appears that the crop has been reduced by 60% to 75%.

Sweet cherries were at tight or open cluster. Orchards located near Lake Michigan suffered little damage. Flower buds in orchards away from Lake Michigan were killed. 

In Plums, European plums at tight cluster suffered no damage close to the Lake and light damage away from the Lake.  Oriental plum flowers were opening and damage seems to be more variety specific with severe damage in some varieties while growers report they still have crop in other varieties. 

Apples are at half inch green to tight cluster.  Damage was widespread and again was due to the stage of development and distance from the Lake.  Early developing varieties were severely affected in Van Buren County with less injury reported in Berrien and Allegan counties.  Later developing varieties suffered much less damage.  According to the Enviroweather disease forecasts light scab infections occurred at a few sites on April 4.   Growers need be ready for apple scab.   

Pears buds are tight cluster and damage does not seem severe.  Pear Psylla adults were out before the freeze.

Small fruit

Blueberry fruit buds are swollen and are starting to burst in early varieties. Blueberries generally suffered little damage the freeze.  Early developing and blooming varieties showed browning of the buds.  The ovules were generally viable but the damaged corolla will not open so these flowers will not set fruit.  Older dead flowers were noted in several varieties from winter injury but these losses were generally light.  Green leaf tissue did show browning and damaged tissues are more susceptible to mummyberry.  Mummyberry treatments after a hard freeze are effective at reducing mummyberry.

Grapes: Concord buds are at early swell and vinifera grapes at scale crack.  Losses to the freeze were wide spread.  Growers report from 60 to 30 percent loss of the primaries.  The losses are very variable due to site exposure, bud development and distance from the lake.  Grapes were bleeding from fresh pruning cuts indicating that the sap was up and the buds were active.  It will be easier to determine the potential crop after warm weather returns and bud swell of the live buds (both secondary and primaries can be seen.

Strawberries are putting out new leaves and the trusses are visible in the crown of the plant. Covered strawberries were not severely damaged by the freeze.

Raspberries are quarter inch green.  We have not yet assed damage in brambles, but we expect that the growing points were damaged and the plants will be set back but we should see good regrowth.

Cranberries are dormant.

Miscellaneous

Growers are pruning and clearing brush.

The next Monday Fruit Update meeting will be, Monday April 16, at the Fruit Acres Farm in Berrien County.  The first Grape IPM meetings in Van Buren and Berrien Counties will be on Thursday April 17. The morning meeting will be from 10 AM to noon at the Cronenwett Farm Shop at 70123 28th Street east of Lawton. The afternoon meeting will be at 2 PM in the Berrien County MSU Extension Office at the Southwest Michigan Research & Extension Center.  These meeting are co-sponsored by National Grape Cooperative and MSU Extension and are open to all grape growers.  There are RUP credits available for both the Monday Fruit Updates and the Grape IPM meetings.