2026 Disease Update: Mitigating Brown Rot on Stone Fruit

Peaches and nectarines have started to ripen, which means 'tis the season for brown rot. Pre-harvest brown rot management should be underway, especially for varieties to be harvested soon. The fungus causing brown rot is quite opportunistic: it can kill blossoms and ruin the fruit you have worked hard all season to grow. Brown rot is favored by warm, wet weather. Compared to 2025, conditions this season so far favor low to moderate brown rot disease pressure. Growers still want to be mindful and be sure the fruit is protected. How you manage disease in the field will help control latent brown rot infections after harvest.

Spores produced on early-maturing cultivars can fuel a continuing outbreak on late-maturing cultivars. To add another headache to the issue, insects can be important vectors of the fungal spores during fruit ripening: they can carry spores to injury sites produced by oriental fruit moth, Japanese beetle, green June beetle, and other insects that can injure fruit. Wounded fruits are much more susceptible to brown rot than unwounded fruit. It is critical to be on top of insect management. Keep in mind: under the right conditions, "healthy" fruit harvested can be contaminated and may decay later during storage.

This is a reminder of how to manage preharvest brown rot. Research at Rutgers showed that applying sprays 18, 9, and 1 days before harvest provided greater than 95 percent control of brown rot under heavy disease pressure. At Penn State FREC, we have slightly modified this preharvest spray regime to give growers a bit more wiggle room, aiming for a 3-day window at each time point (21–18, 11–9, and 3–1 days before harvest).< When following this regime, be sure to rotate chemistries by FRAC Group number for resistance management. For example, one could spray the following (provided the maximum number of sprays has not been exceeded for that chemistry):

21-18 day: Fontelis (FRAC Group 7; 0 day PHI)

11-9 day: Indar (FRAC Group 3; 0 day PHI)

3-1 day: Merivon (FRAC Groups 7 +11; 0 day PHI). 

Other options to rotate:

Miravis (FRAC Group 7; 0 day PHI)

Tesaris (FRAC Group 7; 0 day PHI)

Luna Sensation (FRAC Groups 7 + 11; 1 day PHI)

Luna Experience (FRAC Groups 7 + 3; 0 day PHI)

Luna Flex (FRAC Groups 7 + 3; 7 day PHI)

Pristine (FRAC Groups 7 + 11; 0 day PHI

Topsin M (FRAC Group 1; 1 day PHI)

Cevya (FRAC Group 3; 0 day PHI)

Inspire Super (FRAC Groups 3 + 9; 2 day PHI)

Tilt (FRAC Group 3; 0 day PHI)

Quash (FRAC Group Code 3; 14 day PHI)

Vangard (FRAC Group 9; 2 day PHI)

Flint Extra (FRAC Group 11; 0 day PHI)

Captan (FRAC Group M4; 0 day PHI)

These fungicides are not a complete list of available options for managing brown rot on stone fruit. Be aware of the products used to control blossom blight, and ensure compliance by reviewing the current use regulations and the product label. Depending on the number of sprays needed and what you may have used during bloom time, be sure to practice fungicide resistance management and rotate chemistries by FRAC group ("Spray by the Numbers"). If Captan was sprayed during the cover sprays, tank mixing is not necessary during the preharvest period.

Alternative options for brown rot management

The key for growers who farm organically or prefer using alternative products is to spray as often as possible, manage insects, scout regularly, and promptly remove infected fruit as soon as you see it. Spraying regularly ensures continuous protection; removing infected fruit from the trees reduces the number of spores available to cause disease and, hopefully, minimizes the risk of an epidemic. Dropping infected fruit to the ground will be enough to limit the spread. Vigilance is important, and this may mean spraying every few days, especially if rain washes the products off. According to studies at Rutgers, sulfur is considered a weaker fungicide for controlling brown rot. Over the last several years, our field testing has shown efficacy for Serenade ASO, Double Nickel, and Oso.

Managing other stone fruit and apple diseases during the summer

For managing bacterial spot, cherry leaf spot, sooty blotch and flyspeck, and bitter rot, refer to the May 27, 2026 Disease Update. 

For additional resources

Dr. Tree Fruit and Don Podcast

Penn State 2026 – 2027 Tree Fruit Production Guide

For commercial fruit growers, please note: When controlling for disease, weather, and tree growth conditions need to be monitored at a local level within one's own orchard. To support management decisions (especially during infection events), growers can use the NEWA website, which provides weather data from weather stations across Pennsylvania.  Before applying chemical products, be sure to comply with current use regulations and read the product label. Product information can easily be obtained from CDMS, Agrian, or Greenbook.