Tips To Identify Bacterial Diseases On Stone Fruit [Slideshow]

Both bacterial spot and bacterial canker are destructive bacteria that infect stone fruit. Let’s take a look at some of the predisposing factors to infection, symptoms to watch for, and tips to help you avoid problems in your orchard this year.

Bacterial Spot
Symptoms limit yields and in some cases, 100% fruit loss has been observed. Bacterial spot can be confused with the fungal disease peach scab, however the symptoms are different.

Unfortunately, there are few effective controls for bacterial spot. Cultivar susceptibility in early bud break and early fruit ripening can favor the occurrence of bacterial spot. Sandy and clay soils also predispose trees to this bacterial disease. Disease is favored by hot, humid, and wet conditions. Wind and wind-blown sand can increase the severity of bacterial spot by creating wounds for bacteria to enter.

Bacterial Spot Management
There are two primary strategies for bacterial spot management. One is to plant bacterial-spot-resistant cultivars. These cultivars are not immune to the bacteria, so control measures will still need to be applied especially if there is high disease pressure and susceptible cultivars are planted nearby.

The other management strategy is using chemical control. Copper can be applied; however, there is a risk of phytotoxicity and resistance. Growers can also apply oxytetracycline, which is often applied as many as 10 times during a season if disease conditions persist. The risk with oxytetracycline is possible antibiotic resistance, persistent yield loss, and label imitations.

Bacterial Canker
Bacterial canker is most problematic on sweet cherry varieties. This is a cold-weather disease, with epidemics seen most in cold, frost-prone areas in the spring. This infection limits tree life and productivity and is caused by several bacteria. Losses due to fruit lesions are sporadic. The infection moves into the trunk and limits production and causes tree decline.

Some of the predisposing factors that favor the occurrence of bacterial canker include the training system, cultivar and rootstock susceptibility. Trees planted with the Modified Central Leader and Spanish Bush are most susceptible, whereas the Perpendicular V system is the least susceptible. Bacterial incidence is likely in sweet cherry cultivars such as Sweetheart and Lapins. Bing has also shown to be susceptible. Gisela rootstock is highly susceptible to bacterial canker.

Soils with nutrient deficiencies, including a low nitrogen rate, low soil pH (below 5.5), and high nematode populations can favor the occurrence of bacterial canker.

The bacteria produce proteins that increase the freezing temperature of water. Consequently, when bacteria are on the surface of the plant, frost damage can occur thereby predisposing the plant to disease since the bacteria feeds on the nutrients released by the injured plant tissue. During bloom, bacterial populations increase 10 to 100-fold. Autumn rains and cooler temperatures can cause higher rates of bacterial colonization, and infection at leaf scars can be high. When trees are exposed to severe temperatures, the chance for infection increases.
Winter pruning may also cause bacterial canker.

Bacterial Canker Symptoms In Fruit
Sporadic symptoms may be seen, including water damage with soaked lesions, brown lesions, and spots.

Bacterial Canker Management
Management of bacterial canker includes keeping trees healthy. Remove and prevent plant stressors by maintaining adequate nutrients and soil pH. Control nematodes in the soil. Plant trees in well-drained soils. Weeds support bacteria populations, so keep weed populations low. Remove wild Prunus. Old trees are a source of bacteria; do not inter-plant new trees with old trees.

Reduce bacteria before trees enter susceptible periods. Copper sprays such as a Bordeaux mixture with Canola oil (2.8 quarts Canola oil per 100 gallons) may be applied in the spring as well as September, October, and November to help reduce bacteria bacterial populations.

Avoid large, dormant cuts when pruning. Minimize the impact of disease with summer pruning. Keep in mind the 12-inch rule with stub pruning, distancing infection from the main trunk.

Topics: , , , ,

Leave a Reply

Fruits Stories
GrapesTable Grape Commission Awarded More Funding To Study Postharvest Treatment
April 16, 2015
The research will ensure California grape exports continue uninterrupted. Read More
Tom West Blueberries family
BerriesUrban Sprawl Doesn’t Stop 4th-Generation Florida Farm From Growing
April 16, 2015
Growing in town supports the evolution of Tom West Blueberries. Read More
Golden Rice
CitrusMore Social Commentators Changing Their Views On GMO Crops
April 15, 2015
Could public opinion be swayed by evolving narration on genetic modification? Read More
FruitsNew Protective Coating Available For Bee Hives
April 14, 2015
Sustainable crop management company Biobest has announced the launch of “Bee-Coat,” a new protective coating for bumblebee hives. It is Read More
Gala green tip apple bloom
Apples & PearsApple Scab Spores Begin To Emerge In Pennsylvania
April 14, 2015
Now is a good time to apply copper sprays to protect trees. Read More
FruitsRecord Low Snowpack In Washington State
April 14, 2015
Experts say snowmelt occurring earlier than expected. Read More
Crop ProtectionMore Help Needed To Track Brown Marmorated Stink Bugs, Georgia Researchers Say
April 14, 2015
This pest, a problem in apples, tomatoes, and other fruit in the North, has recently moved into Georgia.    Read More
The Latest
Natalie Parkell and Kevin Osburn of Vertical Horizon Farms
CitrusSmall Family Farms Can Survive [Opinion]
April 17, 2015
It is reassuring amid the corporate climate the agriculture industry has experienced in more recent times that there is still room for the little guy, and — more importantly — a need. Read More
Golden Rice
CitrusMore Social Commentators Changing Their Views On GMO Cr…
April 15, 2015
Could public opinion be swayed by evolving narration on genetic modification? Read More
FruitsNew Protective Coating Available For Bee Hives
April 14, 2015
Sustainable crop management company Biobest has announced the launch of “Bee-Coat,” a new protective coating for bumblebee hives. It is Read More
FruitsRecord Low Snowpack In Washington State
April 14, 2015
Experts say snowmelt occurring earlier than expected. Read More
Crop ProtectionMore Help Needed To Track Brown Marmorated Stink Bugs, …
April 14, 2015
This pest, a problem in apples, tomatoes, and other fruit in the North, has recently moved into Georgia.    Read More
CitrusFlorida Agriculture Rings Up Record $4.2 Billion In Int…
April 13, 2015
Accomplishment represents third year in a row that Sunshine State exports have topped the $4 billion mark. Read More
CitrusForecasters Predict Historically Weak Atlantic Hurrican…
April 9, 2015
Extended range outlook cites El Niño as culprit in what could be one of the least active seasons in recent memory. Read More
One World Challenge Wall
CitrusToday’s Youth Set To Sustain The World [Opinion]
April 9, 2015
A select group of University of Florida students are thinking of innovative ways to meet the challenges of supporting 9+ billion people on Earth by 2050. Read More
Food SafetyChipotle Serves Up Food Safety Grants To Five Florida F…
April 8, 2015
Awards in the amount of $1,000 will go to help the winning operations pay for a third-party audit. Read More
Crop ProtectionIR-4 Announces Pest Management Solutions Workshop
April 8, 2015
The IR-4 Project announced their first Global Minor Use Priority Setting Workshop Sept. 20-22 in Chicago, IL. Read More
non-gmo label leafy greens
CitrusNational Farmers Union Supports Mandatory GMO Labeling
April 3, 2015
Organization calls on Congress for unified standards to bridge several pending labeling proposals. Read More
CitrusRainfall Relief Welcomed Across South Florida
April 3, 2015
Below-average precipitation for the region during March helps lower high water levels from what has been a rather wet Dry Season. Read More
CitrusEPA Says It Is Unlikely To Approve New Neonicotinoid Ou…
April 3, 2015
The agency is waiting until new bee data has been submitted and pollinator risk assessments are complete. Read More
FFVA Emerging Leaders Class 4 visits Tallahassee
CitrusMarch On Tallahassee A Fruitful Exercise For Florida…
April 2, 2015
Road trip to the state capital beneficial for Florida Fruit & Vegetable Association's board of directors and Class 4 of its Emerging Leader Development Program. Read More
CitrusCalifornia Snowpack Is Virtually Gone
April 2, 2015
With the lowest water content since 1950, the governor orders first-ever mandatory water reductions in cities and towns, and growers face tighter regulations. Read More
Farm ManagementUSDA Awards $31 Million In Grants To Help SNAP Particip…
April 1, 2015
Funding supports programs that help participants in the Supplemental Nutrition Assistance Program afford healthy foods. Read More
Farm ManagementHow To Save Money In Your Garden
April 1, 2015
Utah State University Cooperative Extension explains how you can save a bundle. Read More
Washington Capitol building
Food SafetyBill To Halt Patchwork Of State GMO Labeling Laws
March 31, 2015
Reintroduced bill includes a new provision allowing for labeling products as GMO-free via USDA-certification process. Read More