SW Michigan Fruit Update

Check the Index for earlier postings

Southwest Michigan, April 12, 2009

Mark Longstroth, Bill Shane

Weather

The weather for the two weeks was mild, with highs in the 50s and 60s and lows around freezing.  A spring snowstorm brought heavy snow to the area, on April 6.  The overnight lows have not been low enough to cause damage to swollen buds.  We would need temperatures below 25F or lower to cause freeze injury to most crops.  These cool weather conditions are expected to continue and I expect continued slow crop development

We will no longer post a large Growing Degree Table for MAWN stations in Southwest Michigan You can find that information at the Enviroweather website. Click on a station close to you.  Here is a link a table of SW Michigan’s Growing Degree-Days base42 from March 1 to April 12, 2009, and a comparison of the regions Growing Degree Days base 42 to April 21 in past years.

Southwest Michigan Growing Degree Day Totals March 1 through April 12, 2009				Grapes, from April 1
Location	GDD 42	GDD 45	GDD 50	GDD 50
SWMREC:	136	93	45	5
Fennville:	105	70	31	5

 

Tree fruit

Fruit tree buds are swelling.  Growers still have the opportunity to apply dormant sprays to reduce overwintering disease inoculum.

Apricots are at white bud.  We may see open flowers later this week.

Peaches buds are swelling.  The most advanced fruit buds are at green caylx and some leave buds have leaf tips emerging.  It is too late to apply controls for peach leaf curl but there is still an opportunity to apply oil sprays to reduce San Jose scale.

Both sweet cherry and tart cherry buds are swollen and green tissue of the bud scales is visible, most buds are at green side.  ‘Balaton’ cherries are at green tip.  We are at the end of the window for copper on sweet cherries dormant spray to reduce bacterial canker.

In Plums, European plum buds are at white side.  Oriental plum buds are at tight cluster.  San Jose scale has been a problem for plums in Southwest Michigan and oils can still be used in the European varieties.  It is probably to late to use oil on the Japanese plums after bud burst.

In Apples, development is widely scattered.  Early apple varieties are at quarter inch green. Midseason varieties are at green tip.  Late varieties are still at silver tip.  We expect that we will not be to tight cluster by this time next week.  No insect activity to report.  Oil sprays to control aphids, mites and scale can be delayed until pink.  If you plan in using oil you should avoid using sulfur of Captan at this time.  Because of the phytotoxic interaction between oil and sulfur, oil is applied early in organic production systems and copper is used at green tip for scab control.  Scab spores are available for infection.  Growers should be ready to apply apple scab sprays as green tissue appears. We have not yet had an apple scab infection event.  There have been confirmed cases of resistance to the strobilurin fungicides in Michigan apple scab.  There is no reason to believe that resistance to these materials is not in Southwest Michigan as well.  Growers will need to pay close attention to the use of different materials with the increase of resistance to our most effective fungicide tools.

Pears buds are swollen and bud scales have separated.  Pear Psylla eggs are being laid.

Small fruit

In small fruit, now is the window for lime sulfur applications in blueberries, grapes and brambles to suppress diseases that overwinter on the plant.

Blueberry fruit buds are swelling and leaf buds have green tissue exposed.  In the earliest varieties fruit buds are beginning to burst.  It is time to look for mummyberry mushrooms.  Growers with Putnam scale problem may want to use dormant oil sprays to reduce this pest.  Avoid using oil sprays if you have recently used lime sulfur as the oil and sulfur can cause plant injury if green tissue is present.  The Michigan Blueberry IPM Newsletter is posted at the MSU Blueberry IPM Update Newsletter.  The first Blueberry IPM Update meeting is planned for

Grape buds are generally tight but terminal buds on long spurs are showing scale crack in the Paw Paw area.  Growers are tying canes.  There will be a Grape IPM Meeting at SWMREC on April 23 at 7 PM.

In Strawberries, new leaves have emerged and flower trusses are visible in the crown.

In Raspberries, most buds are dormant, but buds at green tip and quarter inch green can be found.  Now is the window for Lime Sulfur applications to suppress anthracnose.

Cranberries are dormant.

Miscellaneous

Growers are pruning and clearing brush.

The Fruit Code-A-Phones in Van Buren (269) 657-8217 and Berrien (269) 944-4126 ext 1, are being updated.  The next Monday Fruit IPM Update meeting will be, Monday April 20, at the Fruit Acres Farm in Berrien County.