SW Michigan Fruit Update
Van Buren MSUE Home
Fruit Pages

Check the Index for earlier postings

Southwest Michigan, May 11, 2009

Mark Longstroth, Bill Shane

Weather

Last week was cool with highs in the 60s and lows in the 40s.  Soils are beginning to dry out.  Scattered frost Monday caused little damage.  Temperatures on Tuesday morning were low enough to cause damage to most fruit.  Warm rain as thunderstorms are forecast for Wednesday.

Southwest Michigan Growing Degree Day Totals March 1 through May 10, 2009				Grapes, from April 1
Location	GDD 42	GDD 45	GDD 50	GDD 50
SWMREC:	471	362	222	182
Fennville:	409	312	184	159

You can find weather and IPM information for Southwest Michigan at the Enviroweather website.  Here is a link a table of SW Michigan’s Growing Degree-Days from March 1 to May 2, 2009.  Our heat accumulations are close to 2008 but behind the averages for recent years, here is a comparison of Growing Degree Days to May 10 in past years.  There are also maps showing the current Degree-day accumulations for the state and the departure from the long term average. 

Tree fruit

Fruit growers should look for plum curculio feeding and egg laying when warmer evening temperatures return later this week and next.  Stone fruit that is out of the shuck is accessible to this pest.

Apricots are out of the shuck.  Fruit size varies from 10 to 16mm depending on the variety.

Peaches are in the shuck. Crop potential looks very good for much of the area.  No symptoms of bacterial leaf spot or peach leaf curl have been found.  Oriental fruit moth egg laying has begun.  Growers with nectarines should check to see if western flower thrip are present in the shuck where they cause scarring of developing fruit.

Sweet cherries are beginning to emerge from the shuck.  The largest fruit are 6 to 8 mm.  Potential crop loads vary greatly by variety. Sweet cherry fruits are always susceptible to brown rot.  Because the leaves are out growers also need to protect against cherry leaf spot.  Black cherry aphid is causing distortion and gumming of leaves.  Growers should scout for plum curculio as the fruit emerges from the shuck next week.  Plum curculio generally begins egg laying when we have warm night temperatures.

Tart cherries are in the shuck.  Leaves have emerged and many growers have applied cherry leaf spot materials.

In Plums, European plums are at petal fall.  Oriental plums are in the shuck.  Growers should apply fungicides to reduce black knot in plums as shoot growth begins.

Apples are at petal fall.  Cool weather for the next week will not be favorable for apple thinning.  We suggest that growers wait for warmer weather and lager fruit.  I hope that there will be a good thinning window when the fruit is 8 to 10 mm in diameter.  Few apple scab symptoms have been found.  Many more symptoms from recent scab infections should show up this week.  Cool weather has kept the risk of fire blight low.  Use the new model for fireblight on the Enviroweather website to track disease development.  Insect activity is increasing.  Leafroller larvae have been found.  Spotted tentiform leafminer adults are flying and laying eggs.  European red mite eggs have hatched.  Oriental fruit moths are flying in good numbers.  Codling moths were trapped last week in southern Berrien County (May 3).  We expect a strong flight when warmer nights return. 

Pears are past petal fall.  Fruit are 4 to 6 mm in diameter.  Pear scab is a concern with infection conditions similar to apple scab.  Pear growers can use the apple scab model at the enviroweather site to track pear scab.  Pear Psylla eggs and nymphs are hard to find.

Small fruit

Blueberry bloom is underway.  More cold injury is apparent in reduced flower numbers.  Growers should focus fungicide applications on mummyberry.  Shoots are about one inch long and leaves are unfolding so the young shoots are very susceptible to infection if we get any prolonged wetting or freezes.  The Michigan Blueberry IPM Newsletter is posted at the MSU Blueberry IPM web site .  The first Blueberry IPM Update meeting is planned for 6 – 8 PM on May 13 at the Bodtke Farm at 01240 57^th Street, west of Grand Junction MI.

Grape shoots are about 3 inches long with leaves unfolding and flower buds exposed.  Many growers have applied fungicides to suppress disease development, especially phomopsis.  Feeding by grape flea beetle larvae can be found on new leaves.  See the most recent copy of Grape IPM Newsletter at the MSU Grape current conditions webpage.  Here is a link a table of SW Michigan’s Growing Degree-Days from April 1 to May 10, 2009.  Low temperatures on Monday caused damage to foliage in lower canopy of some area vineyards.

Strawberry bloom is started underway and many growers made ice with their frost control systems Monday morning.  Growers should be prepared to apply fungicides

Raspberry shoots are elongating and more leaves are out.  Winter injury in blackberries is severe in most areas.

Miscellaneous

Growers are planting trees and applying fungicides.

The Fruit Code-A-Phones in Van Buren County (269) 657-8217 and Berrien County (269) 944-4126 ext 1 are being updated. The next Monday Fruit IPM Update meeting will be, Monday May 18, at the Fruit Acres Farm in Berrien County.