SW Michigan Fruit Update

Check the Index for earlier postings

Southwest Michigan, July 22, 2008

Mark Longstroth, Bill Shane

Weather

Weather over the last two weeks has been seasonal with highs in the 80s and lows in the 60s.  Several storms have left significant rainfall.  Precipitation totals for the last few weeks are1.5 to 3 inches.  Soils are moist.  Rainfall totals for the Fennville station since January 1 is 24 inches compared to 16 inches for the SW Station in the Benton Harbor region. 

Southwest Michigan Growing Degree Day Totals March 1 through July 20, 2008				Grapes, April 1
Location	GDD 42	GDD 45	GDD 50	GDD 50
Berrien Springs:	2198	1891	1432	1422
Scottdale:	2103	1806	1361	1353
SWMREC:	2104	1784	1343	1337
Bainbridge:	2099	1804	1364	1357
Hartford:	2081	1702	1268	1264
Lawton:	2173	1869	1406	1401
Grand Junction:	2202	1900	1444	1438
South Haven:	1986	1699	1277	1270
Fennville:	1940	1651	1217	1213

Tree fruit

Leaf sampling for nutrient analysis is generally done from the end of July to early August.  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 are still active and will be around for another 3 to 4 weeks.  Immature stinkbugs are becoming easier to find.   Pheromone dispensers in insect traps need to be changed for many of the common types used.

In Apricot, the harvest of midseason varieties such as Hargrand and Harlayne is underway.  Quality is generally good with little brown rot problems.

Peach fruit are about 2 to 2.5 inches in diameter.  Some young peach plantings have red hued leaves of nitrogen deficiency brought on by excess rain.  Harvest of PF-1 and Queencrest began approximately July 9; PF5B started July 15 followed by Harrow Diamond and Early Star.  Harvest of Bright Star begins later this week.  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.  Leaf loss due to bacterial spot continues on very susceptible varieties such as Babygold 5 and Suncrest peaches and Flavortop nectarines.  Stinkbug puncture wounds to fruit will become more obvious as the current cohort of these bugs mature.  Watch for western flower thrip damage to peach and nectarine fruit when hot weather returns. Delegate offers a new option for thrip control.  Oriental fruit moth adult catches continue to be high for the second generation.  Growers should consider the need for control measures against larvae of this generation.  Oriental Fruit Moth pheromone disruption dispensers may need to be replaced.  Trunk spraying for peach tree borers is nearly done.

Sweet Cherry harvest is finished.  Quality and prices were generally good with only moderate cracking.  Alternaria fruit rot was only a minor problem.  Post harvest pruning can be done now.  General recommendations (see Fruit Cat Alert for July 26, 2005) are to:  prune no later than early September; avoid exceptionally heavy pruning; do not prune trees that have not filled their space.   For triangular shaped trees, the height of the bearing area of the tree should be no more than 3X the clear alleyway width.  For rectangular shaped trees, the height of the bearing surface should be twice the drive alleyway distance.

Tart Cherry harvesting has ended for Montmorency.  Balaton harvest continues.  Fruit quality was generally very good with only minor problems with deep sutures and wind-induced bruising.   Balaton fruit quality has been good, with a wide range of fruit sizes.  Growers have been applying post harvest fungicide sprays to control cherry leaf spot.  Yellow leaves are common, but most of these are due to bacteria canker leaf infections.  Cherry leaf spot infections are becoming easier to see but this disease is relatively light in most orchards.

Plum varieties be harvested are Early Golden and Methley with Shiro and Early Magic shortly thereafter.  Early European types are beginning to ripen, among the first expected next week is Vibrant.  Growers should scout for white apple and potato leafhoppers. 

Apples are 2 to 2.8 inches in diameter.  Fire blight infections are still moving down infected branches but generally no new infections are showing up.  Sooty blotch and flyspeck are a concern although symptoms are scarce; fungicides for this should be included in cover sprays.  Trap catch for codling moth continue to be low for most orchards.  Codling moth larvae can be found in the fruit.  Apple maggots have been caught for several weeks in SW Michigan.  Obliquebanded leafroller larvae are becoming easier to find but still feeding mainly on leaves for now. The new insecticides Delegate and Altacor seem to be doing a good job controlling this insect.  Spotted tentiform leafminer trap catches continue to be high.  Green apple aphid numbers are still building.   White apple leafhopper leaf stippling can be found in some orchards but is generally scarce.  Leaf bronzing due to European red mites and apple rust mites is easier to find.  San Jose scale adult trap catch is very low and red spots on apple fruit due to crawlers are showing up in a few orchards.  Green aphid populations are still active on terminal leaf growth.  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 2 inches in diameter.  Pear psylla numbers are generally low.  Sooty blotch and flyspeck are a concern; fungicides should be included in cover sprays.  Both codling moth and oriental fruit moth can damage pear fruit at this time. 

Small fruit

Blueberry harvest of Bluecrop began last week marking the beginning of the main season varieties and heavy harvest volumes.  Japanese beetles and 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 cluster tightening.  Crop potentials vary greatly from vineyard to vineyard, depending on frost damage received.  Due to light crops last year, crop load potential was high coming into 2008.  Vineyards with heavy crops may have difficulty in ripening the crop this year if the heat unit accumulation is not high in the next two months. Growers are applying their second postbloom spray.  Grape berry moth trap catches are up indicating the start of the second generation.  Larval stings and split berries are easy to find in vineyards with light crop and minimum sprays.  Grape leafhoppers are scarce.  Wine grapes need to be protected from potato leafhoppers.  Japanese beetles are easy to find.  Fungicides at this time should target all four major fruit diseases; powdery mildew, downy mildew, black rot and phomopsis.  Black rot berry symptoms have been found in unsprayed vineyards as well as downy mildew.  Berry susceptibility decreases as veraison begins.  Phomopsis lesions in the fruit clusters can be found.  The fruit becomes resistant but the cluster rachis is always susceptible to this disease.  With the frequent heavy rains recently we expect significant losses to this disease.

Strawberry regrowth is underway from renovation.  Growers should protect against potato leafhoppers to prevent hopper burn and stunting of new growth. 

Raspberry and Blackberry harvest is continues.  Growers should be prepared to protect against Japanese beetles. 

Cranberries are at pinhead and small green fruit.

Upcoming Meetings

There is a Grape IPM meeting this Thursday in Berrien County at Bob Dongvillo’s Farm, at 6 PM.  The next Monday Fruit Update meeting will be on Monday August 4, at the Fruit Acres Farm in Berrien County. The last two meetings of the season are on a biweekly schedule.

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