SW Michigan Fruit Update

Check the Index for earlier postings

Southwest Michigan, June 23, 2008

Mark Longstroth, Bill Shane

Weather

Last week’s weather was cool and dry with highs generally near 70, and lows near 50.  A few showers passed through the region on Saturday, leaving little rain and some light hail.  Soils are becoming dry.  We expect warmer temperatures later in the week with highs rising into the 80s and lows near 50. Our GDD totals are now about 3 or 4 days behind 2007. 

Southwest Michigan Growing Degree Day Totals March 1 through June 22, 2008				Grapes, from April 1
Location	GDD 42	GDD 45	GDD 50	GDD 50
Berrien Springs:	1393	1170	850	840
Scottdale:	1383	1161	840	832
SWMREC:	1305	1093	787	781
Bainbridge:	1316	1106	802	795
Hartford:	1250	1044	748	744
Lawton:	1382	1163	840	835
Grand Junction:	1398	1180	863	857
South Haven:	1222	1020	727	720
Fennville:	1194	988	694	690

Tree fruit

Deer browsing continues.  Insect activity remained high.  Leaf roller larvae are feeding in some orchards.  Tarnished plant bug feeding damage has been reported in apples and peaches.  Adult rose chafer and Japanese beetles are continuing to emerge. Aphid numbers are building.  We are catching lesser peach tree borer.  Trunk sprays or pheromone disruption are recommended for borer control.

Apricot fruits are 1.5 to 2.5 inches in diameter. 

Peach fruit are about 1.5 inches in diameter.  Pit hardening has not yet begun.  Powdery mildew and bacterial spot but not peach scab, have been reported.  Most curled leaves caused by green peach aphids are empty indicating that they are migrating out of the orchard and control is no longer needed. 

Sweet Cherry fruit are showing red color and birds are a problem.  Early varieties are being harvested.  General harvest of early varieties should begin late this week.  The cool dry weather has suppressed brown rot infection.  Brown rot requires warm, wet conditions, 5 to 6 hours of wetness at 70F and growers should be prepared to protect against this disease at harvest.  Rains Sunday were cherry leaf spot infections in some areas.

Tart Cherry fruit are coloring.  Most fruit are straw colored and ethephon sprays will be applied soon.  Recent rains were a cherry leaf spot infection.  Few cherry leaf spot symptoms have been reported.  An eastern cherry fruit fly was caught this week in Berrien County.

Plums are almost an inch in diameter and the pits are hard.  Shoot growth has stopped and growers no longer need to protect against black knot.  Plum trees also need to be protected from the peach tree borers.  Growers should scout for white apple leafhopper.

Apples are 1.5 inches in diameter.  Some varieties such as Red Delicious and Empire have a light crop.  Apple scab symptoms can be found so growers with active scab should continue to protect against scab infection.  Soon, waxy fruit will be resistant to scab.  Fire blight infections are larger and easier to find but overall is relatively light for the region.  There is little oozing due to the dry conditions.  Trap catch for codling moth remains high.  We are now in about midway through egg hatch.  Obliquebanded leafroller adults were trapped June 9 and egg hatch should be beginning.  Spotted tentiform leafminer trap catch is rising indicating the beginning of the second generation.  White apple leafhoppers are scarce.  European red mites are moving about.  San Jose scale adults are flying.  Sprays for San Jose scale crawler should be targeted for the end of the week. Green aphid populations are climbing.  Young trees should receive sprays to kill Potato leafhoppers. 

Pears are about an inch in diameter.  The crop looks good. 

Small fruit

Blueberry fruits are beginning to color.  Harvest of early varieties in the south should begin in a little over a week.  Cranberry fruitworm egg hatch is ending.  Fruitworm feeding damage is easy to find in most fields.  Look for shriveled blue berries in the clusters of green fruit.  Cherry fruitworm only attack single fruit while cranberry fruitworm will move to other fruit in the cluster.  Preharvest fungicide sprays should target alternaria and anthracnose.  Blueberry maggot traps should be out. 

Grape berries are BB sized.  Shatter continues.  Rose chafer numbers are declining but they can still be found feeding on late blooming clusters of the secondary and tertiary buds.  Grape leafhopper can be found in many vineyards.  Insecticides to control grape berry moth should be included in the post bloom fungicide sprays.  Grape berry moth trap catches are up and larvae can be found feeding in the fruit clusters.  Wine grapes need to be protected from potato leafhoppers.  Fungicides in the immediate post bloom period should target all four major fruit diseases; powdery mildew, downy mildew, black rot and phomopsis.  So far phomopsis is the only disease that is easy to find in vineyards.  Wine grape growers also need to apply sprays to control botrytis bunch and berry rot.

Strawberry harvest is ending in some areas begun.  Warm temperatures and dry conditions following the rains of June 5-7, have moved the crop rapidly.  Fruit size and quality are excellent.  Cool conditions should extend the season.  Leather rot and sap beetles can be found in some fields.

Raspberry and Blackberry bloom is ending.  Some fruiting canes are looking weak due to winter injury.  Plants on sandy ground are showing signs of drought stress.  Growers should be scouting for Japanese beetles, raspberry sawfly larvae and leaf roller larvae.  Raspberry sawfly eats the leaves between the veins look for small green bristled worms under the leaves.  Leaf rollers curl and web the leaves together.  Raspberry cane borers are laying eggs; look for wilting shoot tips and a ring of parallel girdles at the base of the wilting.  The egg is laid between the girdles.  Primocanes in fall bearing raspberries are 18 to 24 inches tall.

Cranberries are nearing full bloom.

Upcoming Meetings

The next Monday Fruit Update meeting will be, Monday June 30, at the Fruit Acres Farm in Berrien County.

The annual Viticulture Day at the Southwest Michigan Research and Extension Center will be July 30.  The cost is $20 before July 18 and $25 after July 18.  A registration form is available at the Van Buren County MSUE Website; http://web1.msue.msu.edu/vanburen/vitregform.pdf