SW Michigan Fruit Update

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Southwest Michigan, June 16, 2008

Mark Longstroth, Bill Shane

Weather

Last week’s weather was generally dry with highs near 80, and lows in the 50s and 60s.  Scattered storms passed through the region over the weekend.  These storms brought rain and hail in some areas.  Rainfall totals from these storms were generally light, from a tenth to less than an inch.  Soil moisture levels are falling and sandy soils are becoming dry.  We expect cool temperatures for the coming week with highs in the near 70 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 15, 2008				Grapes, from April 1
Location	GDD 42	GDD 45	GDD 50	GDD 50
Berrien Springs:	1245	1043	757	747
Scottdale:	1233	1032	746	738
SWMREC:	1161	971	699	693
Bainbridge:	1179	990	718	711
Hartford:	1124	939	674	670
Lawton:	1237	1038	750	745
Grand Junction:	1251	1054	771	765
South Haven:	1087	906	647	640
Fennville:	1061	877	617	613

Tree fruit

Deer browsing continues to be a problem in many fruit plantings.  The warm temperatures increased insect activity.  Leaf roller larvae are feeding in some orchards.  Young trees should receive sprays to kill Potato leafhoppers.  Tarnished plant bug feeding damage has been reported in apples and peaches.  Rose chafer is out and Japanese beetles are emerging.  Obliquebanded leafroller adults were trapped last Monday, indicating the flight of the overwintering generation has started.  Aphid numbers are building.  We are catching lesser peach tree borer.  Trunk sprays or pheromone disruption are recommended for borer control.

Apricots fruits are almost 2 inches in diameter. 

Peach fruit are 1 to 1.5 inches in diameter.  Growers are hand thinning excess fruit.  Oriental fruit moth egg hatch has ended and few shoot strikes have been reported.  Pit hardening has not yet begun.  Bacterial spot has been report but not peach scab or rusty spot (powdery mildew).  Bacterial spot has been reported but not peach scab or rusty spot (powdery mildew).  Green peach aphid populations are climbing.

Sweet Cherry fruit are coloring and showing red color.  Harvest of early varieties such as ‘Cavalier’ 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.  The weekend rains were cherry leaf spot infections in some areas.

Tart Cherry fruit are coloring.  Growers should wait until all the fruit are straw colored before applying ethephon sprays.  Recent rains were cherry leaf spot infections in some areas.  No cherry leaf spot symptoms have been reported.  Bacterial canker symptoms can be found on tart cherry leaves and fruit. 

Plums are almost an inch in diameter and the pits are hardening.  Growers still need to protect against black knot.  Plum trees also need to be protected from the peach tree borers. 

Apples are an inch in diameter.  Fruit drop over the several weeks has been heavy and for some varieties the crop is very light.  Apple scab leaf symptoms can be found in sprayed orchards.  These lesions will release spores during every rain.  Growers with active scab should continue to protect against scab infection.  Waxy fruit is resistant to scab.  Fire blight infections are becoming more common but they are not severe in most orchards.  Trap catch for codling moth remains high.  We are now in the treatment window for codling moth and egg hatch is underway throughout the region.  Spotted tentiform leafminer will form leaf mines soon.  White apple leafhopper is hard to find.  European red mites are moving about.  San Jose scale adults are flying.  Sprays for San Jose scale crawler should be targeted for 300 GDD50 after biofix (June 1), about June 20. Green aphid populations are climbing.

Pears are 24 mm in diameter.  The crop looks good. 

Small fruit

Blueberry fruits are growing rapidly.  Cranberry fruitworm trap numbers are still high, and controls have been applied to many fields.  Post bloom fungicide sprays should target anthracnose.  More growers are reporting dead blossom clusters caused by phomopsis infections of the flower clusters.  Shoestring symptoms are easy to find. 

In Grapes, Concord and Niagara bloom is ending.  Wine grapes are blooming.  Rose chafer was common is some vineyards.  Grape leafhopper can be found in many vineyards.  Insecticides to control grape berry moth should be included in the post bloom spray.

Strawberry harvest has 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.  Growers should be scouting for Japanese beetles.  Raspberry sawfly larvae and leaf roller larvae are feeding in some plantings.  Raspberry sawfly eats the leaves between the veins, while 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 witling.  The egg is laid between the girdles.  Primocanes in fall bearing raspberries are 12 to 18 inches tall.

Cranberry bloom has begun.

Upcoming Meetings

The next Monday Fruit Update meeting will be, Monday June 23, at the Fruit Acres Farm in Berrien County.

There is a twilight grape IPM meeting Thursday, June 19 at Tim Seppala's farm, southeast of Lawton at 6 PM. 

There is a Blueberry IPM meeting Wednesday June 24 atCarini Farms in Ottawa County.