Stone Fruit: Now’s Your Chance!

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 ( to learn more, especially about his brown rot resistance management program (ProfileTM).

Leave a Reply

Featured Stories

All Vegetables Stories >All Fruits Stories >All Nuts Stories >All Citrus Stories >

The Latest

BerriesReal Estate Firm, Wish Farms Strike Large Land Deal
October 1, 2014
$13.8 million transaction includes more than 800 acres acquired from longtime Central Florida produce operation. Read More
VegetablesFind The Right Market For Your Crops
October 1, 2014
Getting to know the demographics of your market is key to maximizing your return on investment. Read More
Insect ControlBagrada Bug And Brown Marmorated Stink Bug Posing Threa…
October 1, 2014
Two species of stink bugs are now posing a serious threat to agricultural production in the Western U.S.: the brown Read More
OrganicResearchers Breeding Organic Tomato Varieties Receive $…
October 1, 2014
Purdue University accepts funding to lead multi-institution research to breed organic varieties that will resist foliar diseases. Read More
Vegetables14 Quality Cabbage Varieties [Slideshow]
October 1, 2014
Browse the slideshow below for information on cabbage varieties from the nation’s leading seed breeders and distributors. Read More
FruitsOrganic And Local Food Economies Receive More Than $52 …
October 1, 2014
Most of the grants were authorized through the 2014 Farm Bill. Read More
Insect ControlMore Than 600,000 Acres Removed From Golden Nematode Re…
October 1, 2014
The potato acreage was taken off the Animal and Plant Health Inspection Service’s list; under 6,000 acres in New York are still considered to be infested. Read More
Crop ProtectionTool Helps Track Insects On The Move At Night
October 1, 2014
Signals collected by the National Weather Service’s Doppler radar network may serve as an early warning system to track corn earworm, a major pest in sweet corn. Read More
NutsNew Walnut Budding, Grafting, and Planting Video Releas…
October 1, 2014
Lake County nurseryman Alex Suchan, who has been grafting trees for two-thirds of a century, is the star. Read More
GenNext GrowersGrowers Need To Be Mindful When Dealing With The Media
October 1, 2014
When being interviewed for a story, preparation is the foundation to help you successfully get your point across. Read More
Citrus Achievement AwardSharing Is Caring When It Comes To Curing Citrus Greeni…
October 1, 2014
Mike Sparks, 2014 Citrus Achievement Award winner, says being open with peers about what's working and not working is crucial in managing HLB. Read More
Florida Ag ExpoKnow How To Knock Back Nematodes
October 1, 2014
The 2014 Florida Ag Expo will provide critical tips in soilborne pest management. Read More
CEU SeriesCEU Series: Vow To Vanquish Weeds Among Vegetables
October 1, 2014
Herbicidal neglect can and will kill your crops. Read More
Insect & Disease UpdateUF Names Interim Director For Citrus Research And Educa…
September 30, 2014
Michael Rogers has been a central figure in Florida’s battle to survive greening. Read More
BerriesPractice Persistence When Battling Botrytis In Blueberr…
September 30, 2014
Cognizance of resistance is key to managing formidable fungus. Read More
CitrusFarming Is Quite The Scary Prospect For Some [Opinion]
September 30, 2014
Florida Grower managing editor Paul Rusnak says economic realities might frighten off future leaders from noble professions. Read More
FruitsNew Suppress Herbicide Gets Green Light From EPA
September 30, 2014
Approval gives organic growers new weed management tool. Read More
BerriesNew Fill-By-Weight Clamshell Filler For Blueberries
September 30, 2014
Lakewood Process Machinery's equipment offers a simplified user interface, minimized drop heights, a new dribble-gate system designed for an increased level of accuracy. Read More