SW Michigan Fruit Update

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April 11, 2006

Mark Longstroth, Bill Shane, Al Gaus

Weather

Last week was relatively mild.  Temperatures were generally above 50 and near freezing at night.  A hard freeze occurred on the morning of Saturday April 8, with temperatures into the low 20s. Little damage was reported.  Growing Degree Day accumulations are about average for this time of year.  This week’s forecast is for much warmer weather, with highs near 70 and lows near 50. This should move all fruit quickly so that our bud stages are more similar to last year when we have been about a week ahead of normal.  The longer the warm weather lasts the more advanced we will be.  This also means that our fruit will be more susceptible to frost when the warm weather ends.  Rain and thunder storms are forecast for later in the week and rain Sunday and Monday, these could be infection periods for early fruit diseases if the wetting periods last long enough.

Southwest Michigan Growing Degree Day Totals March 1 through April 9, 2006				Grapes,  April 1
Location	GDD 42	GDD 45	GDD 50	GDD 50
Scottdale	126	85	45	9
SWMREC:	109	77	40	7
Bainbridge:	122	86	46	10
Hartford:	103	72	37	6
Lawton (est.)	110	80	37	9
Grand Junction:	128	90	50	10
Fennville:	100	72	39	8

Tree Fruit

Tree fruits are past the swollen bud stage. The window to apply copper is closing rapidly.

Apricot buds are first white and we should see bloom next week.  Poor growth in some sites and varieties indicates that there was some winterkill of fruit buds.

Peach buds are generally at green caylx.  Some winter fruit bud loss has been reported in some varieties and on lower, colder sites.  This damage is more common in inland areas away from the lake.  We are at the end of the window for applying oil to peaches to kill San Jose scale. Oil applications should probably not be applied after red calyx, which will be in a couple days at these temperatures.  With warm weather we may see bloom late next week.

Both sweet and tart cherries are past the swollen bud stage; early sweet cherries are at green tip, most sweets are still at green side, Montmorency tart cherries are generally at green side, but Balaton cherries are more advanced at green tip. Growers are applying copper to reduce bacterial canker.  We expect to see white bud next week.

In Plums, Oriental plum buds have burst and are at tight cluster and will probably bloom next week. European plums buds are at white side in Berrien County and swollen bud in the rest of the region.  Bloom is still a couple weeks off.  Black knot control normally begins at bloom when shoot growth starts, but if you have black knots in the orchard apply controls as soon as green tissue emerges. 

Apples are at green tip and growers need to worry about apple scab. Because of the mild winter, scab spores are being released with rains now.  Many growers have applied copper as a protectant against scab.  Some areas were wet long enough of April 8 for a scab infection but generally very little green tissue was exposed.

Pears buds are swollen and the bud scales are separated. Pear Psylla adults are out.

Small Fruit

Blueberry fruit buds are swollen and leaf buds are moving exposing green tissue.  This means that mummy berry shoot strike infection can occur.  Mummy berries have been hard to find. Last year was dry and the mummyberry infection level was low.  Scouts reported that mushrooms were developing last week and the forecast warm wet weather should encourage mushroom development.  Blueberry Growers should check out the MSU Blueberry website at http://www.blueberries.msu.edu

Grapes are breaking dormancy. Buds at the tips of pruned shoots are starting to swell. Some growers are finishing pruning but many have finished tying.  Some growers are applying dormant sulfur and copper sprays to reduce overwintering phomopsis. Sulfur should not be applied to Concord and other sulfur sensitive grapes after bud break when green tissue is present.  Grape growers should look at the MSU Grape Resources Page at http://grapes.msu.edu

Strawberries are putting out new leaves. Growers are applying herbicides, putting down straw mulch and setting up their irrigation systems.

Raspberries are at quarter inch green and new shoots are emerging from the ground. The window for applying delayed dormant applications of lime sulfur is closing rapidly.

Cranberries are still dormant.

Miscellaneous

Growers are finishing pruning, clearing brush and applying herbicides.

The current Fruit CAT Alert should be available at http://www.ipm.msu.edu/fruit-cat.htm the next issue will be April 24.

The next Monday Fruit Update meeting will be, Monday April 17, at the Fruit Acres Farm in Berrien County, at 5 PM.  Grape IPM meetings will be held in Berrien and Van Buren Counties on Thursday, April 20.  Growers should check out the new MSU Weather IPM site at http://www.enviroweather.msu.edu/home.asp