Avoid Blueberry Rust

Avoid Blueberry Rust

Whether in Michigan, California, Hawaii, or elsewhere, blueberry growers must stay vigilant to thedanger of blueberry leaf rust. With epidemics of it occurring sporadically in past years, both in the eastern U.S. and on California’s Central Coast, highbush blueberry crops are at risk unless growers learn to recognize the symptoms and solutions.

Eyes Wide Open

According to Scot Nelson of the University of Hawaii at Manoa’s Department of Plant and Environmental Protection Sciences, leaf rust is caused by Naohidemyces vaccini, formerly named Pucciniastrum vaccinii, and is heteroecious, meaning it has two hosts. It also occurs on many hosts and has two forms in North America — an eastern form and a western form. Hosts of the pathogen include Vaccinium spp. (blueberry, cranberry, huckleberry), Tsuga (hemlock, hemlock spruce), Rhododendron (including azalea), Lyonia, Menziesia (mock azalea), Pernettya, Hugeria, Pieris, Leucothoe, and Oxycoccus.

“Blueberry leaf rust first appears as tiny yellow spots on the upper surface of young blueberry leaves about 10 days after inoculation,” writes Nelson in a 2008 plant disease report. “Spots later turn reddish brown and may be surrounded by a slight yellow halo. The lower leaf surface gathers a yellowish-orange dust, which is associated with the leaf spots. This dust is the spores of rust, and produced in the uredinia, which is at the center of each spot. Yellowish-orange rust pustules soon become visible, scattered over the surfaces of lower leaves. Affected leaves may redden and on heavily diseased plants, leaves often turn brown, curl up, and drop. This defoliation is the principal direct cause of harm to the plant, The indirect effect of leaf loss is reduced plant vigor and poor fruit production.”

In many climates, like California’s Central Coast, leaf rust is active the first four months of the year during fruit production, and young fruit are very susceptible to infection, according to a 2006 “Blueberry Leaf Rust” report by Franklin Laemmlen and Mark Gaskell at the University of California. This combination of fruit production and rust spore activity causes leaf rust to be dangerous economically because infected fruit is unmarketable. While a few leaf spots are not a problem, when fruit infection occurs, berries are a total loss.

In the northern U.S., the fungus overwinters in infected leaves and reinfects hemlock needles in early spring; however, it needs both species — blueberry and hemlock — to complete its life cycle in cold climates. In the southeastern U.S., where hemlocks do not grow, the fungus overwinters in uredia on evergreen blueberry leaves.

Solutions For Rust

In a Michigan State University Blueberry Fact Sheet released in 2009, experts recommended implementing a preventive control program to control rust, including removing hemlock trees within a third of a mile in northern climates, avoiding susceptible cultivars, limiting overhead irrigation, and applying effective fungicides. Even with frequent fungicide sprays, however, this disease may prove too difficult to manage. Fungicide sprays may also cause phytotoxicity to blueberry leaves, so they must first be tested and tankmixes of incompatible products must be avoided.

Nelson says one of the best ways to control blueberry leaf rust is to plant a resistant variety. A Cornell University online report lists Northern highbush varieties resistant to blueberry rust to include: Bluecrop, Burlington, Collins, Dixie, Earliblue, Gem, Ivanhoe, Olympia, Stanley, and Weymouth. Moderately susceptible varieties are: Jersey, Herbert, Berkeley, Blueray, and Pacific. Susceptible varieties to blueberry rust include: Coville, Pemberton, Washington, and Atlantic.

Topics:

Leave a Reply

2 comments on “Avoid Blueberry Rust

Crop Protection Stories
Disease ControlNew Disease Control Tools For Fruit And Nut Growers
July 29, 2015
Apple scab is a big problem for growers in the Midwest and East. But, a new fungicide boasts efficacy against Read More
Bill Stoneman
Crop ProtectionFormer BPIA Head Relishes Challenge Of New Consulting Role
July 28, 2015
JET Harvest Solutions taps Bill Stoneman for his bounty of biocontrol experience. Read More
Late blight shown in a tomato
Disease ControlLate Blight Identified In Indiana, Michigan
July 28, 2015
A potato field in Michigan and a potato and tomato field in Indiana have documented the disease. Read More
UF/IFAS researcher looks after pigs on weed control duty
More VegetablesGot Weeds? Perhaps Pigs Can Help
July 27, 2015
Old-time crop protection method using hogs now being tested by UF/IFAS researchers. Read More
downy mildew symptoms on basil
Disease ControlRed Lights Slow Down Growth Of Downy Mildew On Basil
July 22, 2015
University of Florida scientists say the technology may help growers manage the disease and reduce chemical inputs. Read More
Bacterial wilt of curcurbits
CucurbitsWin The War Against Bacterial Wilt Of Cucurbits
July 22, 2015
Learn how to identify, the survival and spread, as well as management methods of this vegetable disease. Read More
Crop ProtectionRegional Integrated Pest Management Grants Reduced Pest Risks In The West
July 22, 2015
The program created tools and training information designed for Western growers. Read More
The Latest
Crop ProtectionLettuce Disease Gives E. Coli A Boost
July 31, 2015
E. coli prefer cut, injured, and young lettuce leaves. Read More
Crop ProtectionResources For Knowing Your Soil
July 30, 2015
Getting to know your soil and learning other environmental and natural resources data can be downloaded and is available for use with many computer software platforms for general resource analysis and farm management. Read More
Crop ProtectionNew Fungicide Targets Key Diseases
July 30, 2015
This disease control tool hits two different parts of the fungal life cycle. Read More
Bill Stoneman
Crop ProtectionFormer BPIA Head Relishes Challenge Of New Consulting R…
July 28, 2015
JET Harvest Solutions taps Bill Stoneman for his bounty of biocontrol experience. Read More
Crop ProtectionRegional Integrated Pest Management Grants Reduced Pest…
July 22, 2015
The program created tools and training information designed for Western growers. Read More
Crop ProtectionClue Into Chemigation Best Practices
July 15, 2015
Monitoring performance and quick repairs are critical to successful applications. Read More
Crop ProtectionNew Egg Cage System Could Increase Ladybug’s Bioc…
July 13, 2015
A specialized insect cage system developed by USDA scientists could improve the prospects of mass rearing the pink spotted lady Read More
Crop ProtectionIR-4 Call For Nominations For “SOAR” Award
July 10, 2015
The IR-4 Project, a resource that supplies pest management tools for specialty crop growers by developing research data to support Read More
Crop ProtectionEarly Blight And Septoria Leaf Spot Rampant On Pennsylv…
July 8, 2015
According to a news release from Penn State University, early blight and Septoria leaf spot are present in Pennsylvania tomato Read More
Crop ProtectionDowny Mildew Reported In Ohio Cucumber Fields
July 8, 2015
According to a disease update from Ohio State University Extension, downy mildew was reported in cucumbers on farms in West Read More
Crop ProtectionZeal SC Miticide Now Registered With Liquid Formulation
June 26, 2015
Valent U.S.A. Corporation announced that Zeal SC Miticide has been registered by the EPA with a new liquid formulation that Read More
Crop ProtectionStay A Step Ahead Of Weeds
June 26, 2015
Weed control can be a tricky and costly task made all the more difficult by herbicide resistance and the push Read More
money down the drain
CitrusGovernor’s Budget Veto Likely To Shutter UF/IFAS …
June 25, 2015
A $180,000 increase, plus another $720,000 in funding for program gone in the stroke of a pen. Read More
Crop ProtectionDowny Mildew Makes Early Appearance In Michigan Cucumbe…
June 23, 2015
An alert sent by Michigan State University (MSU) Extension confirms the presence of downy mildew on cucumber leaves in Michigan. Read More
BerriesCaptan Gold 4L Fungicide Now Registered In California
June 16, 2015
ADAMA has received EPA approval for Captan Gold 4L liquid fungicide for use on strawberries, tree fruits, and other specialty Read More
infrared image showing the difference between using crop termination fumigation in the field and not
Crop ProtectionMaximizing Nematode Management In Vegetables
June 12, 2015
Crop termination is the foundation of mitigating the soil pests for the following season. Read More
Crop ProtectionNew Chart Helps Growers Choose The Best Cover Crop
June 9, 2015
USDA scientists have developed a Cover Crop Chart that helps growers determine the best cover crop to meet their management Read More
Bagrada bug
Crop ProtectionBagrada Bug Has The Potential To Spread Throughout The …
June 9, 2015
The bagrada bug has moved into South Texas and has the potential to move to other areas of the U.S., Read More