Pest Of The Month: Bacterial Blight Of Celery

Bacterial Blight of Celery

Identification

The initial symptoms are small water-soaked spots on the upper and lower leaf surfaces. As the lesions expand, they are delimited by leaf veins, which give them an angular appearance. In most cases, the lesions become dark brown. However, under dry conditions they may be lighter in color. The close proximity of seedlings and the environmental conditions in the seedbed at that time (hot and rainy weather) contribute to rapid development of the disease.

Lesions may coalesce to cover large areas of an infected leaf, but rarely appear on leaf petioles. Bacterial blight lesions appear similar to lesions caused by the early blight fungus (Cercospora apii), but are typically smaller, darker in color, and have a more water-soaked appearance. The margin of the lesions are more distinct than that of early blight, and chlorosis occurs more slowly. In addition, fungal growth may be observed on early blight lesions under favorable conditions.

Brown stem is a petiole necrosis of celery caused by the same pathogen. Unlike bacterial blight, which is present every year, brown stem is more sporadic, appearing every five or six years. When it does occur, however, it can be severely damaging to the celery crop. Brown stem causes more curling and stalk rot than bacterial blight. The principal symptom of brown stem is a brown discoloration over the entire petiole. Although brown streaks may be seen along the whole petiole, the base of the stalk receives the greatest amount of damage. Symptoms intensify closer to harvest as the plant approaches maturity.

Survival And Spread

Bacterial blight is favored by warm and humid conditions, and might be difficult to control during wet weather. The bacteria can be spread from plant to plant by rain, irrigation, or on machinery and people. Symptoms appear within days of the bacteria entering a plant’s tissue through natural openings or wounds. The reasons for the sporadic appearance of brown stem outbreaks are unknown, but are thought to be related to unusually wet winters with high humidity, frequent rainfall, and windy conditions.

Management Methods

In seedbeds, mechanical transmission can be minimized by trimming when foliage is dry. Fertility management is important. Growers should avoid foliar application of nitrogen during warm, wet periods and over-fertilization with soil-applied nitrogen. Minimizing mechanical contact with the plants, once set in the field, also may help reduce spread.
A preventive spray program with copper is the primary tool available to growers for the management of the disease. Unfortunately, strains tolerant to copper fungicides have been reported in South Florida. In addition, streptomycin resistance is still widespread despite very limited use in the Everglades area over the past few decades.

Topics: ,

Leave a Reply

Disease Control Stories
Apples & PearsDon’t Neglect Overwintering Fire Blight Cankers
June 22, 2015
Canker blight has been seen in Pennsylvania orchards, thanks to ideal weather conditions as of late. Kari Peter of Penn Read More
Disease ControlFMC’s RHYME Fungicide Labeled In California And Arizona
June 18, 2015
RHYME fungicide is now labeled for use in California and Arizona  for control of powdery mildew and black rot in 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
Disease ControlYeasts Found On Plum Surfaces May Protect Against Pathogens
June 16, 2015
Some naturally occurring yeasts may be useful for protecting stone fruits against pathogens that attack after harvest. Scientists at the Read More
Disease ControlTips For Grapevine Trunk Disease Diagnostics, Prevention, and Control
May 28, 2015
Various pathogens and environmental factors are considered to be major threats to the vineyard’s health. Pathogens are disease-causing organisms such Read More
Disease ControlPotential New Peach Disease In California
May 28, 2015
Last year, disease levels were very low in the cling peach growing districts of California. Still, several diseases continue to Read More
A view from a low-altitude helicopter shows avocado groves in south Miami-Dade County.
Disease ControlEyes In The Sky Provide Early Detection Of Destructive Avocado Disease
May 27, 2015
Study using multispectral photography helps scientists successfully scout out laurel wilt-affected trees. Read More
The Latest
BerriesRainy Weather Causing High Risk For Phytopthora In Berr…
June 29, 2015
With the rainy weather the Midwest has recently received, the conditions for Phytophthora diseases increases. An increased risk for oomycetes, Read More
Disease ControlQuintec Fungicide Receives Label For Bacterial Spot Sup…
June 26, 2015
Quintec fungicide from Dow AgroSciences, known as an effective treatment for suppressing bacterial spot in peppers, is now available to 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
Apples & PearsDon’t Neglect Overwintering Fire Blight Cankers
June 22, 2015
Canker blight has been seen in Pennsylvania orchards, thanks to ideal weather conditions as of late. Kari Peter of Penn Read More
Disease ControlFMC’s RHYME Fungicide Labeled In California And Arizona
June 18, 2015
RHYME fungicide is now labeled for use in California and Arizona  for control of powdery mildew and black rot in 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
Disease ControlYeasts Found On Plum Surfaces May Protect Against Patho…
June 16, 2015
Some naturally occurring yeasts may be useful for protecting stone fruits against pathogens that attack after harvest. Scientists at the Read More
Disease ControlTips For Grapevine Trunk Disease Diagnostics, Preventio…
May 28, 2015
Various pathogens and environmental factors are considered to be major threats to the vineyard’s health. Pathogens are disease-causing organisms such Read More
Disease ControlPotential New Peach Disease In California
May 28, 2015
Last year, disease levels were very low in the cling peach growing districts of California. Still, several diseases continue to Read More
A view from a low-altitude helicopter shows avocado groves in south Miami-Dade County.
Disease ControlEyes In The Sky Provide Early Detection Of Destructive …
May 27, 2015
Study using multispectral photography helps scientists successfully scout out laurel wilt-affected trees. Read More
Disease ControlPartnerships Key To Healthy Northwest Vines
May 26, 2015
Washington’s grape industry has seen accelerating growth over the past several decades. That momentum is owed, in part, to the Read More
Disease ControlInland Desert Nursery Is Main Source For WashingtonR…
May 26, 2015
The Judkins family has been in the business of clean grapevines for more than 40 years. Today, their Inland Desert Read More
Apples & PearsApple Scab Alert
May 18, 2015
Kari Peter of Penn State University Extension warned growers of possible apple scab and fire blight infections following the rainy Read More
Disease ControlHow To Control Disease During Rainy Weather
May 18, 2015
The recent warm, wet weather conditions are prime for fungal and bacterial diseases, says Annemiek Schilder of Michigan State University Read More
Crop ProtectionBioWorks Launches Two New Versions Of RootShield Biofun…
May 5, 2015
BioWorks, Inc., has launched two new versions of its popular RootShield® biological fungicide, RootShield Seed Treatment and RootShield AG. RootShield Read More
Phytophthora spore under a microscope
Disease ControlResearchers Find Silver Lining In Phytophthora Fight
May 5, 2015
A team of researchers from the University of Florida, University of Central Florida, and the New Jersey Institute of Technology Read More
Apples & PearsConditions Present For High Fire Blight Risk In East
May 5, 2015
“Folks, it’s shaping up to be another doozy of a spring for fire blight and you must heed the warning. Read More
Crop ProtectionExpect The Unexpected With Plant Diseases
May 1, 2015
Whether or not you are a basketball fan, it’s hard not to notice all the publicity and hype surrounding “March Read More