Southwest Michigan, April 30, 2007

Mark Longstroth, Bill Shane, Greg Vlaming

Weather

Last week temperatures were cool with lows in the 40s.  Monday and Tuesday were nice with highs near 70.  Wednesday and Thursday were cold and rainy with highs near 50. The last two days have been warm and pleasant with highs climbing into the 60s Sunday. We accumulated between one to two inches of rain.  Soils are moist.  Scattered thunderstorms brought scattered light hail Monday.  This week’s forecast is for cooler, dry weather with lows in the 40s and highs near 60. Warmer temperatures are forecast for the weekend.

Southwest Michigan Growing Degree Day Totals March 1 through April 29, 2007				Grapes, from April 1
Location	GDD 42	GDD 45	GDD 50	GDD 50
Scottdale	450	356	230	123
SWMREC:	426	334	215	117
Bainbridge:	426	338	218	118
Hartford:	412	324	209	114
Lawton	477	384	258	138
Grand Junction:	433	346	225	113
South Haven	367	287	185	92
Fennville:	346	266	164	84

Tree fruit

Plant growth and insect activity are moving quickly with warmer temperatures. Reports of damage to fruit plantings from the Easter freeze continue to come in.  The two days of rain on Wednesday and Thursday (April 25 and 26) were cold (~47F) but long enough (40 to 65 hours) to be an infection period for many diseases.

Peach bloom is ending.  We should have a good assessment of the peach crop as it emerges form the shuck in the next few weeks.  Oriental fruit moth adults are being caught in good numbers in pheromone traps.  Biofix was Saturday, April 21 at 230 GDD at SWMREC.  Pesticide sprays are targeted for 150 to 200 GDD base 45 after Biofix; this timing would be this weekend.  The first generation of Tarnished plant bug adults have been seen in trees during warm weather.  Last week’s rains could have caused brown rot infections (48 hours at 50F for infection).

Tart cherries are at petal fall and bloom is ending.  Copper would be a good material to use to reduce bacterial canker from the cold rain last week.  Growers with little if any crop may want to use copper as their primary cherry leaf spot material also, to reduce their fungicide costs and maintain a healthy leaf canopy for as long as possible.  There was a report of a tart cherry orchard severely damaged by winter cold with many dead trees.  This occurred because the orchard was defoliated last July and did not withstand the February cold snap with temperatures below zero.

Sweet cherries are at petal fall.  Copper is phytotoxic to sweet cherries and should not be used.  Growers should protect against brown rot.  Sweet cherries are susceptible to brown rot at all times.

In Plums, European plums are in the shuck.  Growers should be protecting against black knot and brown rot.  There was also a report of a plum orchard severely damaged by winter cold with many dead trees.

Apples are blooming.  Growers should begin to assess their crop in preparation for thinning sprays soon.  Signs of powdery mildew can be found in apples.  Last week’s rain was a heavy apple scab infection and symptoms should appear next week.  Symptoms from the April 4 infection should be appearing now.  We are updating our Code-A-Phones with fire blight conditions.  The rain was too cold for fire blight and this week will be too cool for the disease.  Warmer conditions on the weekend may pose a risk.  Now is the time to apply Apogee sprays to reduce fire blight and control vegetative growth.  Growers can also check for apple scab and fire blight at the Enviroweather website. http://www.enviroweather.msu.edu/.   Oriental fruit moth is being caught in good numbers in pheromone traps.  Biofix was Saturday, April 21 at 230 GDD at SWMREC.  Pesticide sprays are targeted from 150 to 200 GDD base 45 after Biofix; this timing would be this weekend. 

Pears are petal fall.  Pear scab is similar to apple scab and pear scab symptoms should appear next week as with apple scab.

Small fruit

Blueberries are at pink bud. In many fields there is a heavy set of fruit buds.  Mummyberry mushrooms are out so last week’s rain was probably an infection period.  Growers should check the new Blueberry IPM Newsletter at the MSU Blueberry Site.  No cranberry or cherry fruit worms have been caught yet and scouts should be setting out pheromone traps for these pests.

Grapes: Concord buds are bud burst and vinifera grapes at late swell.  Once the buds have opened there is less damage from cutworms and flea beetles.  There are many live buds swelling in the vineyards.  We are catching a heavy flight of Grape Berry Moth, these are early males and there is no need to treat for these moths.  There are no fruit clusters available to damage at this time.  Grower should begin their early season disease control programs.  Growers should apply protectants before the next rain.  Be sure and check the MSU Grape website for scouting updates.

Strawberries are at white bud.  Wild strawberries have begun to bloom.

Raspberries: Fall raspberries are putting up new shoots.  Summer raspberries are leafing out and some flower buds are visible in some fields.  Some varieties were severely affected by the Easter cold snap.  Blackberries were severely damaged by winter cold (early February) and the Easter freeze.  Advanced shoots were damaged or killed but new growth is emerging.

Cranberries are beginning to green up on the edges of the beds and buds are beginning to swell.

Miscellaneous

Currents and Gooseberries are blooming. 

The next Monday Fruit Update meeting will be Monday May 7, 5 pm, at the Fruit Acres Farm in Berrien County.  We will discuss apple thinning.  There are RUP credits available for the Monday Fruit Updates.