SW Michigan Fruit Update

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May 9, 2006

Mark Longstroth, Bill Shane, Al Gaus

Last week was cool and mild.  High temperatures bounced between 50 and 70 with lows near 40 at night.  A frost Saturday morning (5/6/2006) was scattered and caused no real damage.  Growing Degree Day accumulations are still ahead of normal.  Rain fell Tuesday bringing about a third to half inch of rain.   This was an infection event for most diseases otherwise the weather was dry.  Soils are still dry.  Soil temps are in the mid 50s.  This week’s forecast is for cooler, wet weather, with highs in the 50s and lows above freezing.  
See the new Enviroweather site at http://www.enviroweather.msu.edu/home.asp.

Southwest Michigan Growing Degree Day Totals March 1 through May 7, 2006				Grapes,  April 1
Location	GDD 42	GDD 45	GDD 50	GDD 50
Scottdale:	518	408	258	228
SWMREC:	520	399	241	219
Bainbridge:	544	420	258	224
Hartford:	475	363	218	191
Lawton	551	430	269	254
South Haven (started April 7)	348	275	173	173
Grand Junction:	538	418	261	224
Fennville:	459	348	207	179

Tree fruit

Damage from the April 26, 2006 freeze is still being assessed.   Flat sites with poor air drainage suffered significantly even on the higher fruit sites.  The forecast low temperatures for the next week should keep insect activity low. Tarnished plant bug and plum curculio will be a problem when it warms up.

Apricots are scarce.

Peaches are in the shuck.  Damage is spotty and varies within orchards. Sites with good air drainage still have a marketable crop and many will require thinning.  We set Biofix Oriental Fruit Moth as April 16 with a GDD of 180 Base 45 at SWMREC.  Chemical controls are focused on egg hatch about 150-170 GDD base 45 after Biofix.  We are about 200 GDD past Biofix.  Tarnished plant bug and green peach aphid have been found in peach orchards.

Sweet cherries are scarce.  A few in the treetops are at split shuck.  A few growers with good sites report they still have a light crop.  Most growers report they do not have enough to feed the birds.

Tart cherries: Montmorency cherries are in the shuck.  We probably have a half to two thirds of a full crop.  The crop should be easy to estimate as the fruit comes out of the shuck in the next two weeks.  Growers need to protect against cherry leaf spot.

In Plums, Oriental plums are scarce.  European plums are in the shuck.  We will not have a good estimate of the crop for several weeks.  Growers need to maintain protection for black knot. 

Apple bloom is ending.  Tuesday’s rain was an apple scab infection. Scab symptoms from earlier rains have no been found.   Cool wet conditions this week means that growers need to maintain scab protection.  Powdery mildew from last year has been found on terminals so growers need to protect against this disease.  The forecast cool temperatures will reduce the danger fire blight this week.  Bacteria populations remain low.  This disease should only be a problem if we get severe weather or orchards have oozing cankers.  Growers can monitor wetting periods for scab and fire blight infections at the Enviroweather site.  Redbanded Leafroller is declining.  Leafroller larvae about 6 mm long can be found in apples.  Since these have dark head capsules they are probably not redbanded leafroller.   Aphids can also be found in apples.  Oriental Fruit Moth trap catches are up.  A few codling moths were trapped this week.  Cool weather will drop the trap counts to zero for most of this week.  It is probably not worth setting biofix to these couple days of flight.  We expect the flight to begin again with warm dry weather next week.  Grower have been applying sprays to control rosy apple aphid and spotted tentiform leafminer.  This week will be too cool for thinning. The wet cool weather could set up the trees for a good thinning window in about a week when warm weather returns.  Grower should be prepared to thin apples next week.  Fruit size then should be about 8 mm, just right for thinning. 

Pears are at petal fall. Growers need to protect against pear scab. Pear psylla nymphs are common in some orchards.  Pear blister mite was reported for several small growers.

Small Fruit

Blueberries are blooming.  Cool wet conditions during bloom means that growers should be protecting against mummyberry and anthracnose fruit rots.  Mummy berry mushrooms should be easier to find after the rain.  Traps should be out for cherry fruitworm and cranberry fruit worm.

In Grapes, freeze killed areas are very easy to identify.  Surviving Primary shoots are 4 to 6 inches long so they are visible a long way off. Level areas and dips and hollows were hit hard by the freeze. There are reports of damage to wine grapes.  This freeze was similar to one in April 2002.  In 2002, several weeks passed before secondary bud growth was evident.  The new buds out there now look as if they started before the freeze.  An accurate estimate can be made in about a month when the flower clusters in new replacement shoots are apparent. Growers should continue their disease control programs. 

Strawberries are blooming.  Growers should consider fungicide applications at bloom under these wet conditions. Angular leaf spot is other cold wet weather disease.  This disease is caused by a bacteria so copper sprays are helpful.

Raspberries flower clusters are emerging.  Fall raspberry shoots are 4 to 6 inches tall. 

Cranberry buds are beginning to swell and some areas of the beds are greening up.

Miscellaneous

Growers were busy spraying to cover up in front of the rain forecast for later in the week.

The next Monday Fruit Update meeting will be, Monday May 15, 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, May 25.   There will also be a series of twilight grape scouting IPM meeting in Southwest Michigan. The dates and locations are; June 15 at Tim Seppala's farm, east of Lawton; July 20 at Bob Dongvillo's farm, south of Benton Harbor; and August 17 at Lemon Creek vineyards, Berrien Springs. We will have more information later in May.