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 (www.peachdoc.com) 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

Food SafetyUSDA Issues Updates To Food Safety Modernization Act
September 19, 2014
Water testing, definition of applicable farms based on produce sales among clarifications to proposed rules. Read More
GrapesThird Straight Record Crop For Washington Grapes
September 19, 2014
Numbers expected to climb as more vines planted in the state. Read More
GrapesFrench Winegrowers Face Higher Labor Costs
September 19, 2014
French wineries may come under added financial pressure as the government considers imposing social charges on wages paid to harvest workers with short-term contracts. Read More
IrrigationCalifornia Boosts Local Water Control
September 19, 2014
Governor Jerry Brown signs historic legislation to strengthen local management and monitoring of critical groundwater basins. Read More
VegetablesSakata Seed America Shows Heart Through Charitable Prog…
September 19, 2014
Company’s corporate giving mission bears fruit for the American Heart Association. Read More
Insect & Disease UpdateAdditional Aid Coming For Florida Citrus Growers Gouged…
September 17, 2014
Through USDA’s Tree Assistance Program, eligible growers can cash in on cost share for diseased tree removal and replanting. Read More
FruitsFlorida Fruit & Vegetable Association Seeks Fresh A…
September 17, 2014
New partnership bolsters Fresh From Florida program. Read More
CitrusFDA Announces Cooperative Agreement To Implement Nation…
September 17, 2014
Agreement will provide information to help plan and carry out the produce safety rule in partnership with state regulatory agencies. Read More
NutsAchieving A Super-Premium Walnut Crop
September 17, 2014
What are the best ways to get high quality walnuts that are light in color and fully developed? Read these 8 harvest best practices to find out. Read More
NutsAlmond Growers Highly Dependent On Groundwater
September 17, 2014
Fully 87% of large growers use groundwater to irrigate their trees. Read More
NutsWarm Winter And Drought Casting Doubt On Pistachio Harv…
September 17, 2014
Though Rabobank report says that one billion pounds still attainable by 2019. Read More
Crop ProtectionBagrada Bug On The Move In California
September 16, 2014
Find out more on management tactics and what counties are impacted by this invasive pest. Read More
Cucurbits14 Stand-Out Melon Varieties [Slideshow]
September 15, 2014
Browse the slideshow below for information on these exceptional melon varieties from the nation’s leading seed breeders and distributors. Read More
Grower Achievement AwardView Highlights From The 2014 United Fresh Washington P…
September 15, 2014
Browse this slideshow to view photos from the 2014 United Fresh Washington Public Policy Conference, including pictures of this year’s Grower Read More
Apples & PearsCanneries Hope To Encourage Growers To Grow Pears For P…
September 15, 2014
Higher wholesale prices offered as means to boost canning pear acres. Read More
FruitsDeadline Nearing For Noninsured Crop Disaster Assistanc…
September 15, 2014
Fruit growers who suffered losses due to frost or freeze in 2012 could be eligible for assistance through USDA’S Farm Service Agency. Read More
BerriesBotrytis Gray Mold Pressure Increasing With Humid Weath…
September 15, 2014
Michigan State University researcher offers tips to reduce the spread of spores. Read More
Fruits5 Mistakes You May Be Making With Your Orchard’s …
September 15, 2014
These deadly sins may be hurting your customers’ experience — and costing you money. Read More