Northwest Michigan fruit regional report – July 7, 2015

Sweet cherry harvest is beginning in time for the National Cherry Festival.

Weather report

The holiday weekend was perfect for enjoying northern Michigan! We had warm and dry weather for celebrating the Fourth of July. Daytime temperatures were up in the 80s and fell into the high 50s at night. The warm and dry weather will be helpful for keeping diseases in check. However, rain is predicted to move into the region, and the forecast is for thunderstorms accompanied by heavy rainfall. Overall, we have been dry throughout the region. The last significant rainfall was 0.25 inches of rain June 14. With the recent warm temperatures, we have moved up in our growing degree day (GDD) accumulations: 1,402 GDD base 42 and 817 GDD base 50.

Crop report

Grape shoot growth has been rapid during the past week, making all vineyards look much better at last. Even some severely winter-injured experimental varieties at the Northwest Michigan Horticultural Research Center (NWMHRC) now show numerous strong shoots from the basal area of the vine, enough growing points to rebuild the vine for the 2016 cropping season.

Rose chafer numbers have fallen off throughout the area. Powdery mildew is the principle threat to vines at this time. We have seen some downy mildew infections on wild grapes in the area.

There is now quite a bit of ripe saskatoon fruit on some of the earlier varieties. Growers need to be watchful of pre-harvest intervals in selecting pesticides to be used at this time.

Growers anticipate starting hand-harvesting early varieties of sweet cherries this week. Some early varieties were picked on Old Mission Peninsula over the weekend. Cherries are coming at the perfect time as the National Cherry Festival kicked off over the weekend. Growers have reported that a lot of the fruit that was not pollinated has finally started to fall, and the remaining cherries are looking good. We are concerned about cracking with the potentially heavy rains in the forecast. Growers have done a good job managing brown rot in sweet cherries. Birds are evident in blocks as sweet cherries ripen.

Tart cherries continue to ripen, and the crop appears to look larger in some blocks than we first anticipated. However, the estimate remains at 86 million pounds, and growers have differing opinions if that estimate is too big or too small. We will know in a few weeks as growers anticipate harvest starting the third week of July.

The apple crop continues to size, and growers are disappointed with the frost rings on some varieties. Frost rings are evident in Galas in many orchards. Honeycrisp are looking good and seem to have fewer frost rings in this variety. Some growers are hand-thinning trees where the crop is too big, especially in tops of trees. Estimated harvest dates are close to where they were last year, and the harvest dates will be available this week.

Strawberry harvest is ending this week on many farms.

Growth stages at NWMHRC (July 6, 2015, 11 a.m.)

  • Apples:
    • Red Delicious – 35 millimeter fruit
    • Gala – 33 millimeter fruit
    • Yellow Delicious – 30 millimeter fruit
  • Pears: Bartlett: 27 millimeter fruit
  • Sweet cherries:

    • Hedelfingen – 23 millimeter fruit
    • Napoleon – 22 millimeter fruit
    • Gold – 20 millimeter fruit
  • Tart cherries: 20 millimeter fruit
  • Balaton cherries: 18 millimeter fruit
  • Apricot: 32 millimeter fruit
  • Grapes: Riesling – first bloom

Pest report

As mentioned above, recent weather has been warm and dry, which has been drastically different compared with wet conditions a month ago. Due to this recent dry weather, we have had very few infection periods since the middle part of June. We are currently in the midst of a cherry leaf spot infection period following rain Monday evening, July 6, and Tuesday morning. Prior to this recent rain, the last cherry leaf spot infection occurred a week ago on June 30 when we received very little rain (.01 inch recorded on Michigan State University Enviro-weather) and a cool fog settled over the area which kept conditions humid. Although recent conditions for the most part have not been conducive for new cherry leaf spot infections, the disease is apparent in most orchards and lesions that are sporulating now are likely a result of infections that occurred during the several back-to-back infection periods from late May into early June.

Pre-mature defoliation due to virus and disease is also widespread. In some orchards, this scenario has resulted in too few leaves on trees and growers are concerned about ripening cherries. Additionally, some tart cherry trees seem to have very little growth this season, which may be adding to the concern of early defoliation. Michigan State University Extension encourages growers who have leaf spot to use full covers rather than alternate row middle applications to ensure good coverage of all tissue to prevent new cherry leaf spot infections, and ultimately the potential for additional leaf loss due to cherry leaf spot. Please see the article, “Controlling cherry leaf spot in orchards with existing symptoms,” for more information on control strategies.

Rain on Monday, July 6, could cause cracking and cracked cherries are more readily infected with American brown rot. Birds are also active in cherries at this time and bird-pecked cherries are also a concern for American brown rot infection. Although American brown rot is not prevalent at this time, we have received a few reports of brown rot starting to show up in cherries. However, we would like to remind growers that this fungus can spread rapidly. Alternating the use of Indar and an SDHI prior to harvest is recommended to minimize the development of American brown rot resistance, especially when conditions are favorable for American brown rot development. We also encourage growers to use the Special Local Needs (SLN) label for Indar applications at an increased rate of 12 fluid ounces per acre; this label is available through the Michigan Department of Agriculture and Rural Development. American brown rot resistant isolates and isolates with reduced sensitivity to Indar have been detected in Michigan, and because Indar resistance is quantitative, the increased rate of 12 fluid ounces is the most effective rate for American brown rot control.

This week at the NWMHRC, we found a total of five codling moths and apple maggot traps are going up. Cherry fruit flies are active in low numbers in the region and a total of two cherry fruit flies were captured in traps at the station this week. These two flies were the first cherry fruit flies found at the research station this season. Overnight rains will likely stimulate cherry fruit fly emergence.

Obliquebanded leafroller activity is ongoing and we are continuing to catch low numbers of them (2.4 obliquebanded leafrollers per trap) at the station. However, there were reports of high obliquebanded leafroller populations in some orchards (47 moths in a trap) late last week and early this week; 20 or more obliquebanded leafroller moths in a trap is an indication of a potentially high obliquebanded leafroller population in the orchard, and larvae management will likely be needed to prevent shaking the larvae into tanks at harvest. We expect obliquebanded leafroller larvae will be evident in orchards as these larvae typically become active at approximately 1,405 GDD base 42. Some growers with high obliquebanded leafroller catches are planning to treat for the larvae prior to harvest.

One spotted wing Drosophila (SWD) female was detected in an Alpha lure baited trap July 1 in a sweet cherry orchard near the orchard edge in Antrim County, south of Elk Rapids, Michigan. The orchard is a smaller block, about two acres, surrounded by a wooded area on three sides. The Alpha lure is one of five baits that MSU and the NWMHRC are testing for SWD trap effectiveness. The first SWD detected in the state was found in a Trece lure baited trap in a tart cherry block in Benzie County, and we have not found SWD in that orchard block since the first fly was found June 11.

Meetings and events

The Parallel 45 Vines & Wines/MSU Extension Friday meeting series continues July 10, 3-5 p.m. at Bel Lago Vineyards. Our guest speaker will be George Bird from the MSU Department of Entomology talking about the root biosphere and soil health. There is no charge for this meeting.

The seventh annual Parallel 45 Pig Roast will take place July 18 at Werner and Margaret Kuehnis’s home, 12467 Center Road, Traverse City, MI 49686. The Roast will begin at 2:30 p.m. The cost for the pig and the pig-roaster will be about $550. Portable bathrooms, glasses, plates, silverware, the pig, the keg and tables are taken care of. All attendees should bring a dish to pass and a bottle of wine. The cost will be $10 for P45 members and $15 for non-members.

The 26th annual Viticulture Field Day and steak cookout will be held July 29 at the Southwest Michigan Research and Extension Center in Benton Harbor, Michigan. Informational sessions and the equipment show start at 9 a.m., and the day finishes with the ever-popular steak cook-out. Parallel 45 is working to take a group to the meeting this year, and some expenses may be covered. Contact Duke Elsner at .(JavaScript must be enabled to view this email address) for more details.

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