Northwest Michigan fruit update – August 9, 2022

Tart cherry harvest will finish this week across the region. The apple crop is coloring nicely.

Honeycrisp apple with little red spots all over it.
Photo 1. San Jose scale damage on Honeycrisp at the Northwest Michigan Horticulture Research Center, Aug. 8, 2022. Photo by Nikki Rothwell, MSU Extension.

Weather report

The region received rain on Aug. 7-8. The rainfall varied from weather station to weather station, but all reported rainfall (Table 1). After the rain moved out, the weather cooled considerably, and the humidity dropped. According to Jeff Andresen, Michigan State University climatologist, next week’s weather should be sunny, fair and cooler than in the past few days. The next possible rain event is this coming Saturday, but the chance is low and potentially only scattered showers.

Daytime temperatures will remain in the mid- to upper 70s into the low 80s. Nights will be cool: high 40s to low 50s in our region. The medium range forecast is calling for cooler and drier than normal weather through the third week of August.

Table 1. Rainfall totals for northwest Michigan, Aug. 7-8, 2022.


Rainfall (inches)



East Leland




Elk Rapids






Old Mission










Crop report

Many growers have finished tart cherries for 2022. However, there are still a few operations that are harvesting, but most have moved onto Balatons at this stage of the season. There will be tart cherries left in orchards because some growers did not have a “home” for their fruit. We hope to be able to capture the amount of fruit that is remaining through a survey process at the season’s end.

Growers are harvesting peaches, and peach quality is excellent. The flavor and color of fruit is terrific. We have heard reports of some splitting of fruit with the recent rains in areas that received higher amounts of rainfall.

Apples are coloring up, and the size of the fruit is looking good.

Disease report

Cherry leaf spot is evident throughout the block at the Northwest Michigan Horticulture Research Center (NWMHRC) where we are conducting our efficacy trial. However, this orchard has high levels of inoculum from past year’s trials and UTC trees. Many growers are making post-harvest leaf spot applications now.

Most growers did a good job with controlling apple scab during primary scab season. We have not heard reports or observed fruit scab.

Despite the earlier challenges with powdery mildew, most growers have controlled it in apples. Once growers can see the white mycelium on the leaves, it is too late for applications of fungicides to control powdery mildew.

Pest report

As cherry harvest is wrapping up, spotted wing drosophila (SWD) numbers are likely to rise in blocks with fruit remaining on the trees coupled with no more insecticide sprays. We do not recommend a post-harvest insecticide application for SWD. There are two reasons for this recommendation: 1) This insect has a high potential for resistance, and we want SWD from orchards to mix/mate with populations outside of an orchard block to increase genetic diversity to minimize insecticide resistance development; and 2) SWD populations are set back naturally by winter every year, so an extra insecticide application now will not further reduce the population size for the following year.

As mentioned on Friday, we saw an explosion of San Jose scale males in our apple block at the station. Our numbers have jumped from an average of 28 males per trap on July 25 to an average of 793 males per trap on Aug. 1. We are also starting to see scale damage on the apples (Photo 1). In addition to male San Jose scale, we are seeing crawlers on the traps and is an indicator that the crawler stage is here and materials targeting crawlers should be applied to protect fruit from potential damage.

Codling moth numbers at the NWMHRC remain low this week, with an average of 1.7 moths per trap.

We caught our second apple maggot on a trap this week. Based on reports from the MSU Extension fruit team, apple maggot numbers are higher in unsprayed blocks than normal.

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