SW Michigan Fruit Update

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Southwest Michigan, April 2, 2007

Mark Longstroth, Bill Shane, Greg Vlaming

Weather

Temperatures last week were seasonal but cold weather is forecast for late this week.  Plant development has been rapid and only slowed down a little last week.  Soils have good moisture at this time.  We at about the same GDD totals as in 2000, which was another early warm year.  Green tissue out and forecast lows may cause damage to fruit buds.  The current forecast for the weekend is for windy and cloudy conditions with highs in the upper 30s and lows near 20.  These conditions might cause some damage but are unlikely to cause severe damage.  If the skies clear and the winds die down then temperatures could go below 20.  A radiation frost would cause much more damage than the passage of the cold front with snow.  Follow this link to my frost/freeze page for information on frost freezes.

Enviroweather System

You can access Growing Degree Day data and run predictive models of some insect and disease pests for weather stations in Michigan.  The growing degree-day accumulations below are taken from MAWN weather stations.  I gather weather information and GDD and report them.  MSU has developed a website where you can access this weather data and run predictive models for some insects and diseases.  If you click on the link below and then click on Fruit it will bring up all the fruit models that we currently have. In most cases there are default values that make the model work for that weather station but to truly use the information you need to enter your own information.  This allows you to use the predictive model with the weather information form a similar site and your data to predict pest and diseases at your site.

Southwest Michigan Growing Degree Day Totals March 1 through April 1, 2007				Grapes, from April 1
Location	GDD 42	GDD 45	GDD 50	GDD 50
Scottdale	224	176	114	7
SWMREC:	211	165	106	7
Bainbridge:	211	169	108	7
Hartford:	204	160	102	7
Lawton	235	190	128	8
Grand Junction:	226	181	119	7
South Haven	201	157	99	7
Fennville:	180	128	86	6

Tree fruit

Most tree fruits are at or past bud burst stage.

Apricots are blooming.

Peaches buds are showing pink (calyx red) First pink has been reported on some early varieties. Leaf buds are showing green tissue so the time is past for peach leaf curl sprays.  These sprays should be on before the leaf buds open.

Tart cherriesare at green tip

Sweet cherry buds are bursting and they are at tight cluster.

In Plums, Oriental plum flowers are opening.  European plums buds have burst and are at tight cluster.

Apples are at half inch green.  According to the Enviroweather disease forecasts none of the wet periods we had had have been long enough for a real scab infection.   Growers need be ready for apple scab. Because of the mild winter, we expect scab spores from the leaf litter will be ready as soon as green tissue is available for infection.  Growers should be ready to apply scab sprays.

Pears buds are tight cluster. Pear Psylla adults are out.

Small fruit

Blueberry fruit buds are swollen and are starting to burst in early varieties.Growers should be scouting for mummyberry mushroom development.  Blueberries at this stage of development should be able to withstand temperatures down below 20 and sprinkler systems will not protect below 23 F so growers should not attempt to frost protect with their irrigation system.

Grapes: Concord buds are at early swell at the tips of the shoot and scale crack at the basal buds.  Vinifera grapes are dormant.  Growers are pruning and tying.

Strawberries are putting out new leaves and the trusses are visible in the crown of the plant. Strawberries at this stage of development should be able to withstand temperatures down to about 10 so growers should not attempt to frost protect with their irrigation system.

Raspberries are quarter inch green.  Now is the window for Lime Sulfur applications to suppress anthracnose.

Cranberries are dormant.

Miscellaneous

Growers are pruning and clearing brush.

The first Monday Fruit Update meeting will be, Monday April 9, 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 Update and the Grape IPM meetings.