SW Michigan Fruit Update

Check the Index for earlier postings

Southwest Michigan, April 24, 2007

Mark Longstroth, Bill Shane, Greg Vlaming

Weather

For the last two weeks, temperatures were cool with lows near freezing and highs near 40 for the week after the early April freezes and plant development virtually stopped.  The last 5 days have been warm and pleasant with highs climbing into the 80s Sunday. We accumulated as many GDD (25 base 50) on Sunday as in the previous two weeks.  Next week’s forecast is for cool, wet weather. We have had little rain and soils are drying out.

Southwest Michigan Growing Degree Day Totals March 1 through April 22, 2007				Grapes, from April 1
Location	GDD 42	GDD 45	GDD 50	GDD 50
Scottdale	337	264	170	63
SWMREC:	316	246	158	60
Bainbridge:	320	252	162	61
Hartford:	307	240	155	60
Lawton	365	294	199	79
Grand Junction:	341	271	177	65
South Haven	303	238	154	61
Fennville:	273	209	130	50

Tree fruit

Insect activity increased with the return of warm conditions.  Growth and warmer temperatures make it easy to determine the extent of the injury.  It is apparent that damage from the Easter freeze was very variable due to site and variety differences.   Apple leaves show significant injury but stone fruit leaves, which emerge later show little damage.  We will be assessing the injury for some time to come.

Apricots are beginning to leaf out.  There is no crop.

Peaches are blooming.  A good crop of peaches means that growers need to think about thinning.  A few growers are using ropes to blossom thin peaches.  Growers are also pruning.  Oriental fruit moth pheromone traps should be out.  Pheromone disruption of the first generation works better in mature orchards than in young plantings.  Sustained flight and egg laying begins at about 250 GDD base 45.  Our first flight probably began Saturday 230 GDD at SWMREC, but cooler temperatures may shut down the flight.  Pesticide sprays are targeted for 150 to 170 GDD base 45 after Biofix, this timing would be the middle of next week.  Tarnished plant bug adults have been seen in trees during warm weather.  If we get warm rains growers need to protect against brown rot.

Tart cherriesare blooming. It appears that the crop has been reduced by 75%. Some of the open flowers have good pistils.  Many buds have not moved much since the freeze, indicating they are dead, others are opening but the flowers are deformed.  As the leaves emerge and unfold they become susceptible to cherry leaf spot.  Growers with little if any crop may want to use copper as their primary cherry leaf spot material to reduce their fungicide costs and maintain a healthy leaf canopy for as long as possible.

Sweet cherries are at full bloom. Most trees have more bloom higher in the tree, but many of the pistils are dead.  Damage seems to be very variety specific.  Cultivars on dwarfing rootstocks were more advanced and suffered more damage.  There will be good crop of sweet cherries in some orchards and few if any cherries in others.  Copper is phytotoxic to sweet cherries and should not be used.  If we get warm rains growers should protect against brown rot.

In Plums, European plums are blooming.  Oriental plums are in the shuck.  Growers should be protecting against black knot and brown rot. 

Apples are at pink and open cluster.  Early varieties such as Idared and Zestar began to bloom Sunday.  Green leaf tissues are growing and showing typical crinkled freeze injury.  Most cluster leaves show severe damage. Early varieties were severely affected by the freeze 2 weeks ago.  Later developing varieties suffered much less damage.  We can see differences in the growth of individual flowers in damaged clusters.  Some growers are applying oil sprays for European Red Mite control, but we have found few mites or mite eggs.  Spotted tentiform leaf miners and red-banded leafrollers are flying.  There were no apple scab infections since April 4.  With the beginning of bloom we will be updating our Code-A-Phones with fire blight conditions whenever there is a risk of fire blight in the region.  Growers can also check for apple scab and fire blight at the Enviroweather website. http://www.enviroweather.msu.edu/

Pears are blooming and suffered no damage in the freeze. 

Small fruit

Blueberry fruit buds are swollen.  The crop potential looks good.  Damage from two weeks ago is restricted to early varieties have some brown dead flower buds.  Exposed green leaf tissue shows browning at the tips and damaged tissues are more susceptible to mummyberry.  Mummyberry mushrooms are out.  Checkout the new Blueberry IPM Newsletter at the MSU Blueberry Site

Grapes: Concord buds are at late swell and vinifera grapes at early swell.  Losses appear to be about 50 % of the primaries.  Damage is not as severe as last year or in 2002.  After several years of heavy losses to early spring frosts many growers have left many buds so there is still a good crop potential. It is easy to determine live swelling buds.  Grower should continue with their early season disease control programs.  Work by Dr. Annemiek Schilder indicates that a dormant of delayed dormant application of copper or lime sulfur can give good disease control and that this spray is statically similar to a single early fungicide spray.  This indicates to me how important that early season control is.  I recommend that growers apply their protectant materials soon after bud break to reduce disease pressure.  Grape flea beetles were out this weekend. Be sure and check the MSU Grape website for scouting updates.

Strawberry leaves were singed but the plants are putting out new leaves and the trusses have emerged from the crown of the plant. White flower buds can be found in many fields.

Raspberries: Fall raspberries are putting up new shoots. Shoots that have emerged before the freeze are singed and damaged.  Summer raspberries were also hurt.  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

Growers are pruning and clearing brush and applying early season fungicide sprays.

The next Monday Fruit Update meeting will be, Monday April 30, 5 pm, at the Fruit Acres Farm in Berrien County.  There are RUP credits available for the Monday Fruit Updates.