SW Michigan Fruit Update

Check the Index for earlier postings

Southwest Michigan, July 8, 2008

Mark Longstroth, Bill Shane

Weather

The past two weeks had highs in the low 70s to mid 80s and lows in the 50s and 60s.  Rainfall ranged from about ¾ " in the south to 2" in the northern portion of the southwest district.  Rainfall totals starting at January 1 until now range from around 13" in Berrien County to about 22" at Fennville.

Southwest Michigan Growing Degree Day Totals March 1 through July 6, 2008				Grapes, from April 1
Location	GDD 42	GDD 45	GDD 50	GDD 50
Berrien Springs:	1753	1488	1099	1089
Scottdale:	1743	1479	1089	1081
SWMREC:	1631	1380	1010	1004
Bainbridge:	1657	1404	1034	1027
Hartford:	1578	1330	967	963
Lawton:	1744	1483	1090	1085
Grand Junction:	1759	1499	1113	1107
South Haven:	1560	1315	953	946
Fennville:	1527	1279	915	911

Tree fruit

San Jose scale crawler damage to fruit has been showing up more frequently in recent days.  Mite numbers are increasing but not a problem in most sites.  Japanese beetles emerged in high numbers in some areas this past weekend.  Green apple aphid numbers are still building.  Immature stinkbugs are becoming easier to find.  Deer are feeding on growing terminal ends of young trees. A greater than normal incidence of deep suture of sweet and tart cherry fruit are being seen this year.  This disorder occurs and may be due to hot weather in 2007 during the time fruit buds for 2008 were being formed.

In Apricot, the harvest of Goldrich apricot will begin in a few days. 

Peach fruit are about 1 ¾ to 2 ¼ inches in diameter.  Harvest of “Phil’s Pride” a local white peach and the first for the season will begin in a few days followed by PF-1.  Revised informal guesstimates for fresh market peaches for SW Michigan is approximately 60% of a full crop.  The estimated start of significant commercial Red Haven peach harvest for Berrien County is August 6, according to a degree-day model by Bill Shane.  This is approximately 8 days later than last year.  Powdery mildew and bacterial spot levels are relatively low.  Fresh tarnished plant bug and plum curculio damage is relatively rare. Weed spraying and mowing can drive tarnished plant bug into peach trees.  Watch for western flower thrip damage to peach and nectarine fruit when hot weather returns.   

Sweet Cherry harvest is in full swing with mid season varieties such as Schmidt and Hedelfingen being picked in some places.  Brown rot and cherry leaf spot are relatively rare-- however the green/brown felt-like symptoms of alternaria fruit rot are increasing, especially on fully mature fruit.   Some fruit cracking has occurred but is generally not a problem. 

Tart Cherry fruit coloring has been slowed by cool weather.  Fruit on outside of tree are red with most interior fruit ranging from straw colored to nearly full red.  Mechanical harvests Monday, July 7.  Recent rains were a cherry leaf spot infection.  Few cherry leaf spot symptoms have been reported.  Eastern cherry fruit fly was caught the last week of June in Berrien County.

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

Apples are 1.7 to 2.3 inches in diameter.  Apple scab and fire blight infections are easier to find but overall these diseases are relatively light.  There has been little fire blight oozing due to the dry conditions.  Trap catch for codling moth has declined to near zero for most orchards.  Codling moth larvae can be found in the fruit.  We are now more than halfway through egg hatch for the 2^nd generation.  We expect apple maggot to be flying after the recent rains and apple maggot traps should be out.  Obliquebanded leafroller larvae are hatching and feeding on leaves and fruit. Scouting for small larvae with brown to black head capsules is needed to determine need for control measures.  Spotted tentiform leafminer trap catches are high.  Two mines per leaf is the damage threshold for this generation.  White apple leafhoppers are scarce.  European red mites and apple rust mites are causing bronzing in a few locations.  Red spots on apple fruit due to San Jose scale crawlers are showing up in a few orchards.  Careful monitoring at this point can indicate whether a spray is needed to prevent significant fruit damage.  Green aphid populations are climbing.  Young trees should be examined for potato leafhopper. Dogwood borer moth began emerging in mid June, indicating the need for trunk sprays in orchards with burr knots attractive to the insect.  .

Pears are about 1.5 inches in diameter with June drop ending.  Pear psylla numbers are generally low.  Fire blight can be seen in the area but is not generally a bit problem.

Small fruit

Blueberry harvest began last week, with the harvest of Weymouth.  The general harvest of early varieties began this week in Van Buren County.  Fruitworm feeding damage can still be found.  Blueberry maggot flies are out.  Preharvest sprays primarily target the diseases alternaria and anthracnose, as well as Japanese beetle and blueberry maggot. 

Grapes are at or approaching berry touch.  Concord grape berries are predicted to be at 1/2 of their final weight at 1200 GDD (Base 50F) past April 1.  The current GDD sum is approximately 1000 to 1100, and warmer locations will reach 1200 by the weekend.  Many growers have already applied their second post bloom spray.  Grape leafhoppers are scarce.  Wine grapes need to be protected from potato leafhoppers.  Wine grapes need to be protected from potato leafhoppers.  Grape berry moth trap catches are down indicating the end of the first generation.  Larval stings can be found on some berries.  Fungicides in the post bloom period should target all four major fruit diseases; powdery mildew, downy mildew, black rot and phomopsis. 

Strawberry harvest has ended and growers have begun renovation. 

Raspberry and Blackberry harvest is underway.  Some fruiting canes are collapsing due to disease or winter injury.  Growers should be prepared to protect against Japanese beetles.  Primocanes in fall bearing raspberries are about 3 feet tall.

Cranberry bloom is ending and there are pinhead fruit.

Upcoming Meetings

The next Monday Fruit Update meeting will be in two weeks on Monday July 21, 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