Northwest Michigan fruit regional report – August 19, 2014

Cherry harvest is winding down in northwest Michigan.

Weather report

Higher than normal precipitation and cooler temperatures are predicted for the remainder of August. There is a chance of rain every day this week and although we could receive a significant amount of rainfall, these weather systems are not predicted to produce severe storms or hail.

Crop and pest report

In wine grapes, outcomes of winter injury are continuing to appear in area vineyards in the form of collapsing shoots. The drought stress in recent weeks has exasperated the inability of cold-injured trunks and cordons to keep up with the water demands of shoots and enlarging berries. It is still a bit of a challenge to guestimate the total crop for certain varieties as vineyard condition and crop load vary a great deal between sites. In the last week, we have seen everything from Cabernet Franc with a great crop, down to a Gewurztraminer block where over half the vines appear to be dead. We are still estimating that most Riesling and Chardonnay vineyards run from 30-60 percent of a full crop, but there are places where these are worse.

Powdery mildew is on the upswing, with extensive leaf and fruit infestations. Continued shoot positioning and leaf pulling will improve the situation and aid in getting good spray penetration to the clusters for powdery mildew control now and avoiding cluster rots later in the season.

Insect activity has been light this summer. Hog sphinx, Achemon sphinx and Pandora sphinx caterpillars are now getting large and greatly increasing their leaf consumption as they approach maturity.

Tart cherry harvest is winding down in northwest Michigan. Most growers have or will be finishing up Montmorency this week, and some Balaton orchards have yet to be harvested. Despite this long harvest season, quality of fruit has been good up to the end. We attribute this high quality in part to the cool weather conditions throughout July and into August.

Peach harvest has begun, and quality is good. Some peach orchards were impacted by the harsh winter, but peaches will still be available throughout the region.

Apples are sizing well, particularly with the recent rains. Apples are also beginning to color. Michigan State University Extension will likely begin apple maturity testing in two weeks.

Overall pest and disease pressure in most of northwest Michigan cherry and apple orchards has been low in the last several weeks. Most cherries have been harvested at this point and because insect and disease pressure has been low, some cherry growers are forgoing post- harvest applications for fruit flies and leaf spot.

With the exception of a few rainy days in the last two weeks, conditions have been dry and two-spotted spider mites are noticeable in some orchards. Second generation San Jose scale males are flying and crawlers typically become active approximately two weeks following male emergence. Spotted tentiform leafminer moth numbers are down in the apples at the Northwest Michigan Horticulture Research Station this week, with 28.5 per trap. Obliquebanded leafroller moths are still active in low numbers, and we caught a total of three codling moths at the station this week. We have caught apple maggots in the last two weeks here at the station.

Upcoming meetings

Northwestern Michigan College and MSU are hosting a conference on climate and technology in grape production. Weathering the Climate: Cultivation and Technology in Grape Production will take place Friday, Sept. 5 at the Hagerty Center at NMC’s Great Lakes Campus.

The Northwest Michigan Horticulture Research Center annual open house will be Thursday, Sept. 4 at the Northwest Michigan Horticulture Research Center. Sessions on cherry, grapes and hops will take place.

Dr. Rothwell’s work is funded in part by MSU‘s AgBioResearch.

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