Be Wary Of Wirestem

Wirestem of cabbage

Identification

The disease gets its name from symptoms that occur on the stem at the soil level. Hard, clearly defined, water-soaked brown to red lesions initially appear on diseased stems near the soil line. Later, stems become wiry and slender at the point of the lesion.

Diseased crucifer plants transplanted to the field grow poorly, are stunted, and may eventually die, especially if there is inadequate moisture shortly after transplanting. If infected plants remain alive, they grow slowly, producing a spindly, stunted yellow plant, and often fail to produce a marketable head.

Bottom rot is primarily a problem on cabbage, bok choy, and Chinese cabbage crops. Once head formation begins, lower leaves that are in contact with the soil might become infected with Rhizoctonia.

Survival And Spread

Warm wet soils and delayed seedling emergence are conducive to infection by R. solani. Wirestem develops when the fungus invades the cortical tissue and girdles young stems. The Rhizoctonia fungus is a common soil inhabitant that can survive almost indefinitely in the soil in the form of small, hard, dark-brown, kernel-like bodies called sclerotia. It also can survive pathogenically on alternate hosts and cruciferous weeds, and saprophytically on crop residues.

Management Methods

Encourage rapid seed germination and vigorous growth of seedling by planting high-quality, heat-treated seed in warm, firm, well-prepared seedbeds. Provide adequate, but not excessive fertilization to promote vigorous growth of seedlings. Treat seed with a registered seed-protectant fungicide. Some cultivars may be less susceptible to infection, consult your seed rep for advice.

If transplants are used, do not plant too deep if Rhizoctonia diseases have been a problem in the field. Avoid planting into cold soils, excessive irrigation, poor drainage, and compaction. Discard all seedlings with discolored stems and roots. Avoid fertilizing transplants as nitrogen can delay hardening of transplants and render them more susceptible to attack. Ensure crop residues from the previous crop are thoroughly decomposed before planting. Deep disking to turn over the top six inches of soil will help speed this process. Crop rotation with non-hosts may provide some reduction in wirestem. Control volunteer mustard and other cruciferous weeds in and around fields.

SoilGard (Gliocladium virens strain GL-21, Certis USA) and other biologicals at planting and at regular intervals after planting may help suppress Pythium and Rhizoctonia. See label for specific application types and timings. 

Soil drenches with pentachloronitrobenzine-based fungicides such as Terraclor (OHP Inc.) or Blocker (AMVAC Chemical Corp.) at planting are most effective when used in combination with cultural control strategies. Consult UF/IFAS recommendations for currently labeled fungicides for Rhizoctonia control in cole crops.

Topics: , ,

Leave a Reply

Disease Control Stories

BerriesStudy: Strawberry Web Tool Could Save $1.7 Million Over 10 Years In Fungicide Use
August 5, 2014
UF/IFAS researchers find spray advisory system also benefits the bottom line. Read More
Disease ControlDowny Mildew Hits Finger Lakes Grapes
July 29, 2014
Growers also seeing spike in botrytis infections, vine collapses during growing season. Read More
Apples & PearsAn Awakening To The Value Of Biopesticides [Opinion]
July 25, 2014
With the entry of major suppliers into the biopesticide arena, whether or not biopesticides work is no longer the question. Now, people want to understand how they work. Read More
Apples & PearsPGRs: The Overlooked Piece Of The Biopesticides Puzzle
July 25, 2014
Yield and quality can be as important to growers as crop protection. Read More
Crop ProtectionDon’t Let Your Cruciferous Crops Get Beaten By Clubroot
July 23, 2014
Learn how to ID, the survival and spread, as well as management methods for this vegetable disease. Read More
Disease ControlThree Fungal Diseases Discovered In Pacific Northwest Vegetable Crops
July 23, 2014
Black leg, light leaf spot, and white leaf spot were discovered in Oregon fields according to reports from Washington State University. Read More
Crop Protection4 Methyl Bromide Alternatives To Consider
July 22, 2014
With the phase-out of the popular soil fumigant, it's important to know you have crop protection options. Read More

The Latest

Disease ControlLate Blight Update Reveals Heightened Activity
August 28, 2014
While several states in the Northeast have confirmed the presence of late blight, the disease has not been reported in North Dakota or Minnesota. Read More
Disease ControlFungal Disease Outbreak Hits Pacific Northwest Vegetabl…
August 27, 2014
An outbreak of blackleg, light leaf spot, and white leaf spot can be significant problems in several vegetable crops.   Read More
Disease ControlGrape Disease Bill Presented To California Governor
August 8, 2014
Grower association backs reauthorization of Pierce’s Disease Control Program. Read More
BerriesStudy: Strawberry Web Tool Could Save $1.7 Million Over…
August 5, 2014
UF/IFAS researchers find spray advisory system also benefits the bottom line. Read More
Disease ControlDowny Mildew Hits Finger Lakes Grapes
July 29, 2014
Growers also seeing spike in botrytis infections, vine collapses during growing season. Read More
Apples & PearsAn Awakening To The Value Of Biopesticides [Opinion]
July 25, 2014
With the entry of major suppliers into the biopesticide arena, whether or not biopesticides work is no longer the question. Now, people want to understand how they work. Read More
Apples & PearsPGRs: The Overlooked Piece Of The Biopesticides Puzzle
July 25, 2014
Yield and quality can be as important to growers as crop protection. Read More
Crop ProtectionDon’t Let Your Cruciferous Crops Get Beaten By Cl…
July 23, 2014
Learn how to ID, the survival and spread, as well as management methods for this vegetable disease. Read More
Disease ControlThree Fungal Diseases Discovered In Pacific Northwest V…
July 23, 2014
Black leg, light leaf spot, and white leaf spot were discovered in Oregon fields according to reports from Washington State University. Read More
Crop Protection4 Methyl Bromide Alternatives To Consider
July 22, 2014
With the phase-out of the popular soil fumigant, it's important to know you have crop protection options. Read More
Disease ControlOrganic Spinach Symposium Highlights Downy Mildew Threa…
July 9, 2014
The organic spinach symposium, sponsored by Ready Pac Foods, Inc. addressed the sector’s sustainability efforts and concerns that have heightened as downy mildewspreads without treatment options in sight. Read More
Crop ProtectionMSU Researcher Warns Against Quick Spread Of Botrytis G…
July 8, 2014
Annemiek Schilder discusses how to treat the fungus effectively. Read More
Apples & PearsFire Blight Hits Indiana
July 7, 2014
Janna Beckerman of Purdue University details pruning approach, MaryBlyt software updated. Read More
CitrusValent BioSciences Opens New Biorationals Plant In Iowa…
June 27, 2014
Valent BioSciences Corporation's new $146 million biorationals manufacturing facility will supply the majority of the company's products derived from fermentation. Read More
Apples & PearsNew Fungicide From Syngenta Controls Leaf Spots, Apple …
June 20, 2014
Chemistry to be registered for use on a variety of specialty crops including apples, potatoes, grapes, fruiting vegetables, pears, and cucurbits. Read More
CitrusEnable 2F Fungicide Label Expanded For Citrus Black Spo…
June 16, 2014
Product provides another mode of action for resistance management of emerging disease. Read More
Apples & PearsPromising Alternatives To Antibiotic Fire Blight Contro…
June 11, 2014
As organic growers lose their most-common defense against fire blight, research around the country provides resources and options for control of the bacterial disease. Read More
Crop ProtectionPartnership Brings Fruit, Vegetable Fungicide To The U.…
June 10, 2014
Tacoma AG LLC partners with Agria S.A. to introduce Fortuna 75 WDG fungicide. Read More