MSU Extension Cherries

The 2026 spring has been a mixed bag for Michigan’s cherry growers. This spring follows what climatologists would consider a more “typical” Michigan winter where we saw consistently cold temperatures and ample snow cover. However, as spring approached, there has been a marked diversion in temperatures between the northern and southern halves of the state.

The southern portion of Michigan has been warmer than normal and close to two weeks ahead of seasonal growing degree day (GDD) averages. In this case, cherries came out of dormancy quickly with the warmer-than-normal spring temperatures. However, this region also had incredible swings in temperatures (it was 80.7 degrees Fahrenheit on April 23 and 54.8 F on April 25), and the cold nighttime temperatures that followed those daytime highs caused some damage to the various stages of bloom in tart and sweet cherries.

In contrast, spring in the northern half of Michigan has been a long, drawn-out affair with lingering cold daytime temperatures and nighttime temperatures that have dipped below freezing, at times noticeably below 32 F. In the north, trees have been slowly coming out of dormancy, but those particularly cold nights may have also resulted in some damage to cherries.

To this end, many growers have variable crop loads in their cherry blocks, both across their own farms and certainly across the three primary cherry growing regions in the state. Growers are trying to make economic decisions based on their individual crops. This article is intended to provide some guidance on how intensely to manage orchards with variable crop loads. 

The initial step in determining how to manage cherry orchards with frost damage is to first assess the amount of damage. Wait until enough time has elapsed so that cherries not damaged by frost and were successfully pollinated are starting to properly size. Cherries in the southwest may be far enough along to determine their crop loads, whereas northern growers will need to wait until fruit have a chance to develop more before making an accurate assessment. Cherries that are still in the shuck, brown or very small are not likely to develop further, or it is still too early to determine how much fruit has set. 

Once you know the size of the crop per block, the second decision is whether to harvest that particular block. If you do intend to harvest, minimizing input costs is probably not the best strategy. These economic calculations can help with deciding if managing the block is the best option. Decide whether harvesting a block is worth the input costs, harvest and trucking costs compared to the returns that are expected for the 2026 crop.

While we can assume some lower trucking and harvesting costs with a light crop, we have found in past assessments that such savings are not that substantial in the end. Given the need to manage the crop sufficiently to bring it to harvest, use the typical annual costs of production for your farm as a baseline. You do not need to include establishment costs, land control costs or other fixed costs, as those are already set by the time you make harvest decisions.

Therefore, as a rule of thumb, you can take your normal total variable cash expenses and divide it by the expected price to figure out how many pounds you need to justify harvest. In the 2022 Tart Cherry Cost of Production study, this number was $1,859 an acre on average (see page 8 of the study). Due to inflation since 2022 and other rises in costs such as fuel and fertilizer, let’s round that number up a bit to $2,100 per acre for 2026. If we anticipate that our price received will be 70 cents, then our break-even yield would be 3,000 pounds per acre ($2,100 ÷ $0.70/pound = 3,000 pounds). Meaning, anything above 3,000 pounds will definitely provide revenues above annual costs, and so the crop is worth harvesting. For another example, if the price instead were 60 cents per pound, one would need 3,500 pounds per acre to break even ($2,100 ÷ $0.60/pound = 3,500 pounds).

Now, the above calculations assume that the price is set to the actual price received, versus the maximum price stated by processors for the year. So, if your average grade is 92%, and the maximum stated price is 70 cents, but under the processor’s grading scale, a 92% pays 65 cents, use 65 cents for the calculation. In this case, $2,100 ÷ $0.65 yields a 3,231 pound breakeven yield.

Table 1. Examples of breakeven yields/ harvest thresholds for different prices.

By this time in the season, some of your annual costs will have already been spent. To be more accurate, adjust by subtracting those spent costs from your normal annual variable cash expenses and then dividing the result by the likely price received. However, the rule of thumb approach we suggest in the paragraphs above will lean towards not harvesting in borderline cases.

If you determine a block is not worthwhile to harvest, you can’t just “walk away” for the season, but rather minimally manage the block with fewer inputs. First and foremost, cherry leaf spot control is vital for overall orchard health. This pathogen infects the leaves, and even with no fruit, trees are still susceptible. The leaf spot fungus Blumeriella jaapii infects leaves with symptoms first appearing on upper leaf surfaces as small purple spots often with yellow halos around the spots on the tops of the leaves. As spots accumulate on foliage, the leaves turn yellow and fall from the tree.

The number of lesions required causing leaf yellowing and drop is variable. Sweet cherries can tolerate quite a few lesions before leaf drop occurs; however, Montmorency tart cherries will drop with only a few lesions, signifying the importance of proper leaf spot management. Balaton can have more lesions than Montmorency before leaf drop, but Balaton are just as susceptible to leaf spot as Montmorency.

Premature defoliation from cherry leaf spot can cause serious tree damage. Even late summer (August, early September) defoliation reduces the ability of trees to store photosynthate in roots leading to an overall loss of vigor and leaving trees more susceptible to winter injury and mortality. Early defoliated trees also typically exhibit reduced flower bud formation and often set less fruit the following season. Therefore, you must control cherry leaf spot even if you do not plan to harvest an orchard this season.

A minimally managed cherry leaf spot program that is less expensive can include a rotation of chlorothalonil, captan and coppers. All materials are rated excellent for cherry leaf spot and they are not single site fungicides, so there is less potential for resistance in the leaf spot pathogen. Michigan State University Extension recommends using coppers when temperatures are cool to minimize the potential for phytotoxicity.

Powdery mildew is another disease that affects cherry leaves. Unlike cherry leaf spot, powdery mildew does not need rain to cause infection; this pathogen thrives in hot and dry conditions. There are many materials that work against powdery mildew in cherries, and many rated excellent in the Michigan Fruit Management Guide. There are no resistance issues in powdery mildew, so Pristine and the SHDI components will work against powdery mildew but should not be used for leaf spot control.

Copper fungicides are not effective against powdery mildew. If you are relying on copper for leaf spot control, add another fungicide to the tank for powdery mildew. The most important spray timing for powdery mildew control is the first cover timing (the first spray application after shuck split). In a year with no crop, this timing is even more important as a cost saving measure. Essentially, if you apply a fungicide targeting powdery mildew at first cover timing, you minimize the need to apply fungicides targeting powdery mildew later in the season. 

American brown rot control, on the other hand, becomes a minimal concern in heavily frost-damaged orchards as this pathogen infects the fruit. If no fruit is visible on the tree, brown rot control can be eliminated. Keep in mind that even a small number of fruits on the tree can result in a brown rot infection, and these infected fruits can increase inoculum in subsequent years.

Blocks where cherries will be harvested will need insecticide sprays to ensure marketable fruit. Trees with a low crop load are more likely to have infested fruits as there are simply fewer fruit in which plum curculio, spotted wing drosophila or cherry fruit fly females can lay eggs. If you do not intend to harvest a particular block, insecticide sprays can be eliminated. Stick with the decision to manage or not manage a block because backing off insecticide early will likely lead to infested fruit if fewer fruit are in a block—there is still zero tolerance for larvae in tart cherry fruit at harvest.

For other management strategies, we offer the following recommendations:

• Gibberellic acid is necessary this season to ensure trees will not over-set next year. Here is a great article on using gibberellic acid in cherries.
• Weed control can be minimized but not eliminated, as trees without fruit will require less water. 
• Micronutrients can be reduced unless you see a deficiency. 
• Nitrogen applications can also be reduced, but more than likely spring applications have already been made this season.