Now’s Your Chance To Get Ahead Of Brown Rot

Stone Fruit: Now's Your Chance!

Brown rot (caused by Monilinia species) is a well-known disease of peaches around the world. It tends to be more problematic in areas with high spring/summer precipitation and high humidity. Wind, rain, and insects help to distribute spores to cause flower blossom or fruit infections during the growing season. Spores may also form latent fruit infections that can cause postharvest rots. If infected fruits are left on the tree and not harvested, they may remain there and become mummified (see top photo). In some cases, twig cankers may occur and wound gumming is produced (see bottom photo).

Perhaps you had a dry spring/summer in 2009 and experienced minimal losses due to this disease. Or, maybe you were faced with more rain than usual, the difficulty of making timely fungicide applications, reduced efficacy of materials you have historically used, and the disease simply “got away on you.” I know of cases in South Carolina where either a spring freeze or early season hail storm resulted in crop damage that caused some growers to “walk away” so-to-speak from problem blocks. In the latter case, we recommended a minimal spray program to help ensure that brown rot epidemics would not result but not everyone elected to do this because of cost.

If you had a brown rot problem last year, you have an opportunity this winter to take proactive steps to reduce the potential for a problem in 2010. According to my friend and colleague, Dr. Guido Schnabel (Extension fruit pathologist, Clemson University), orchard sanitation efforts this winter will go a long way to reduce inoculum and disease pressure this coming season. The first step is to deal with mummies. Because they are a source of inoculum for spring infections, these should be carried out of the orchard and disposed of.

At locations where there is a sod row middle and the orchard floor is vegetated, mummies that fall to the orchard floor may have sufficient spring moisture to become active spore producers. In locations where the orchard floor is kept bare by herbicides, mummies may dry out sufficiently so as not to be a problem. The second step is to deal with limbs that have cankers. The best practice is to remove them from the orchard and burn them. However, putting the prunings in the row middle and driving over them with a flail mower (to remove bark) can facilitate a more rapid decomposition and reduce inoculum level considerably. This is a useful practice for limbs that may also be infected by constriction canker (Phomopsis) or fungal gummosis (Botryosphaeria).

Research by Schnabel and colleagues has demonstrated resistance of brown rot fungi to various fungicide classes. Selection for resistance can occur when fungicides with a single site of action are used repeatedly for years. Whatever the reason, the number of tools available and the efficacy of those tools ultimately depend on their wise use by the grower. That is why thorough sanitation (now) is a wise step to take. Careful choice of fungicides during the growing season and rotation of products with different modes of action can help limit resistance development. However, if you did have product failure last year, you may want to visit Dr. Schnabel’s website (www.peachdoc.com) to learn more, especially about his brown rot resistance management program (ProfileTM).

Topics: , ,

Leave a Reply

Stone Fruit Stories
Disease ControlStone Fruit Rots Rampant In East
July 21, 2015
The incidents of fruit rots in both sweet and tart cherries and peaches and nectarines are quite high in Pennsylvania Read More
Apples & PearsWildfires Damage Washington Fruit Businesses
June 29, 2015
More than 1,000 people have been forced to evacuate as a fast-moving wildfire swept into Wenatchee, WA, on Sunday night Read More
Stone FruitFinding A Cold-Hardy Peach Variety Is Not That Easy
June 26, 2015
Peach trees and cold temperatures don’t mix. Just ask growers in the Midwest and East as they are once again Read More
Stone FruitStemilt To Release New Cherry Variety Called Skylar Rae
June 16, 2015
Skylar Rae, is a a new, bicolored cherry variety that is said to have the highest sugar levels of any Read More
Disease ControlYeasts Found On Plum Surfaces May Protect Against Pathogens
June 16, 2015
Some naturally occurring yeasts may be useful for protecting stone fruits against pathogens that attack after harvest. Scientists at the Read More
CitrusNew Herbicide From Syngenta Receives EPA Registration
June 4, 2015
Syngenta’s new Broadworks herbicide is the first HPPD inhibitor approved by the EPA in tree nuts, citrus, and stone fruit. Read More
Disease ControlPotential New Peach Disease In California
May 28, 2015
Last year, disease levels were very low in the cling peach growing districts of California. Still, several diseases continue to Read More
The Latest
Disease ControlCopper Injury And Bacterial Spot Are Easily Confused
August 4, 2015
In her latest bulletin for tree fruit growers, Kari Peter of Penn State University Extension says it is easy to confuse the Read More
Stone FruitThe Strong Staying Power Of The Redhaven Name In Peache…
July 31, 2015
People tend to be nostalgic about peach varieties, but the switch of varieties grown by a region happens for a Read More
ProductionNatural Product Helps Prevent Cherry Cracking
July 28, 2015
Cherry cracking can be devastating to a grower. One day before harvest, everything looks beautiful. Then, it rains, and an entire Read More
Disease ControlStone Fruit Rots Rampant In East
July 21, 2015
The incidents of fruit rots in both sweet and tart cherries and peaches and nectarines are quite high in Pennsylvania Read More
Apples & PearsWildfires Damage Washington Fruit Businesses
June 29, 2015
More than 1,000 people have been forced to evacuate as a fast-moving wildfire swept into Wenatchee, WA, on Sunday night Read More
Stone FruitFinding A Cold-Hardy Peach Variety Is Not That Easy
June 26, 2015
Peach trees and cold temperatures don’t mix. Just ask growers in the Midwest and East as they are once again Read More
Stone FruitStemilt To Release New Cherry Variety Called Skylar Rae
June 16, 2015
Skylar Rae, is a a new, bicolored cherry variety that is said to have the highest sugar levels of any Read More
Disease ControlYeasts Found On Plum Surfaces May Protect Against Patho…
June 16, 2015
Some naturally occurring yeasts may be useful for protecting stone fruits against pathogens that attack after harvest. Scientists at the Read More
CitrusNew Herbicide From Syngenta Receives EPA Registration
June 4, 2015
Syngenta’s new Broadworks herbicide is the first HPPD inhibitor approved by the EPA in tree nuts, citrus, and stone fruit. Read More
Disease ControlPotential New Peach Disease In California
May 28, 2015
Last year, disease levels were very low in the cling peach growing districts of California. Still, several diseases continue to Read More
Stone FruitEarly Cherry Harvest In Pacific Northwest
May 26, 2015
Cherry harvest is off to an early start in the Pacific Northwest reports the Tri-City Herald thanks to a warmer-than-average Read More
Apples & PearsSolve Your Labor Problems From Within
May 26, 2015
Summer is here, which means harvest season is just around the corner. Hopefully you’ll have the crews you need this Read More
Apples & PearsApple Scab Alert
May 18, 2015
Kari Peter of Penn State University Extension warned growers of possible apple scab and fire blight infections following the rainy Read More
Apples & PearsMichigan State University To Host Field Day At Clarksvi…
May 15, 2015
Michigan State University (MSU) will hold a field day on June 23 at Clarksville Research Center, 9302 Portland Road Clarksville, Read More
Protected AgricultureConsiderations Before Purchasing Non-Tunnel Covering Sy…
April 29, 2015
There are several options to consider when deciding to protect against crop losses from rain. Read More
drought sign water crisis
Apples & PearsDiversification: A Response To Drought [Opinion]
April 27, 2015
With Governor Jerry Brown’s announcement of mandatory use reductions, the general public in California is getting a wake-up call on Read More
FertilizerVerdesian Life Sciences Introduces New Phosphite-Free P…
April 21, 2015
Product designed as alternative for nut and stone fruit growers with concerns about MRLs. Read More
Montmorency tart cherries
Stone FruitWinter Storm Surprises Utah Fruit Growers
April 20, 2015
Snow and cold temperatures threatened tart cherries already in full bloom. Read More