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

One comment on “Pest Of The Month: Bacterial Blight Of Celery

  1. […] Pest Of The Month: Bacterial Blight Of Celery – 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 … Brown stem is a petiole necrosis of celery caused by the … […]

Disease Control Stories
Citrus
April 17, 2017
Natural Enemies for Asian Citrus Psyllid
The eventual spread of Huanglongbing (HLB), or citrus greening, to commercial groves in California seems inevitable. But the devastation seen Read More
Crop Protection
April 3, 2017
Silicon: Plant Nutrient and Biocontrol Agent
Editor’s note: Wendy Zellner made an in-depth presentation on silicon and its use as a biocontrol agent in vegetable crops Read More
Alternaria leaf and pod spot of snap bean
Disease Control
March 17, 2017
Prevent Alternaria from Putting Your Snap Beans on the Spot
Learn how to identify, the survival and spread, as well as management methods for this vegetable disease. Read More
Crop Protection
March 11, 2017
How to Stop Plant Diseases Before They Grab Hold
These smart strategies play off the science behind infestations, instead of merely treating symptoms. Read More
Crop Protection
March 9, 2017
Grafting Offers a Surprising Boost to Plants
A Washington State University project aims to improve yields and increase tolerance to Verticillium wilt with grafted plants. Read More
Southern Blight by Schwartz FEATURE
Crop Protection
March 9, 2017
Top Vegetable Diseases to Watch in 2017
We sent out a call to vegetable pathology Extension agents to let us know which diseases are top of mind for growers. Here’s what we learned. Read More
UF/IFAS researcher Cristina Pisani examines ailing avocado tree
Crop Protection
February 27, 2017
New Discovery Smells Like Victory for Florida Avocado Growers
Scientists find naturally occurring repellent that could keep disease-carrying beetles at bay. Read More
sclerotinia
Disease Control
February 23, 2017
Spot Sclerotinia Before It Stops Your Vegetable Crop
Learn how to identify, the survival and spread, as well as management methods for this malady that goes by many names. Read More
Crop Protection
January 31, 2017
Defend Your Cole Crops from Three Critical Diseases
Learn symptoms, causal agents, and control measures for black rot, Alternaria leaf spot, and downy mildew. Read More
Stemphylium leaf spot of spinach
Disease Control
January 20, 2017
Don’t Let Stemphylium Leaf Spot Stump Your Spinach Crop
Learn how to identify, the survival and spread, as well as management methods for this vegetable disease. Read More
Late blight shown in a tomato
Disease Control
January 19, 2017
Clues Found to Block Late Blight’s Blitz on Potatoes, Tomatoes
With food security at stake, breakthrough in genetic research could help prevent more strains of the deadly pathogen from entering the U.S. Read More
potato field
Crop Protection
January 4, 2017
New Potato Insecticide/Fungicide Seed Treatment Available
Syngenta’s CruiserMaxx Vibrance receives EPA registration. Read More
Anthracnose on cucumber
Cucurbits
December 22, 2016
Stay Alert to Anthracnose of Cucurbits
Learn how to identify, the survival and spread, as well as management methods for this destructive vegetable disease. Read More
Dickeya chrysanthemi of potato
Disease Control
December 21, 2016
Two Tips to Improve Your Potato Seed Stock
High-quality seed stock with a guaranteed low incidence of disease is the first step to success. Read More
Cucurbits
December 20, 2016
3 New Fungicide Product Options for Vegetable Growers
Unique modes of action the main feature of modern chemistries. Read More
The Latest
Crop Protection
April 20, 2017
Beetle Battle Burgeoning for South Flori…
Scientists identify more species of pests that vector deadly fungus. Read More
Cucurbits
April 19, 2017
Alternaria Leaf Spot Awareness Can Save …
Learn how to identify, the survival and spread, as well as management methods for this malady. Read More
Apples & Pears
April 18, 2017
Researchers Say it is Time to Scout for …
With bloom underway, the risk for fire blight and scab are high. Read More
Citrus
April 17, 2017
Natural Enemies for Asian Citrus Psyllid
The eventual spread of Huanglongbing (HLB), or citrus greening, to commercial groves in California seems inevitable. But the devastation seen Read More
Crop Protection
April 3, 2017
Silicon: Plant Nutrient and Biocontrol A…
Editor’s note: Wendy Zellner made an in-depth presentation on silicon and its use as a biocontrol agent in vegetable crops Read More
Disease Control
March 17, 2017
Prevent Alternaria from Putting Your Sna…
Learn how to identify, the survival and spread, as well as management methods for this vegetable disease. Read More
Crop Protection
March 11, 2017
How to Stop Plant Diseases Before They G…
These smart strategies play off the science behind infestations, instead of merely treating symptoms. Read More
Crop Protection
March 9, 2017
Grafting Offers a Surprising Boost to P…
A Washington State University project aims to improve yields and increase tolerance to Verticillium wilt with grafted plants. Read More
Crop Protection
March 9, 2017
Top Vegetable Diseases to Watch in 2017
We sent out a call to vegetable pathology Extension agents to let us know which diseases are top of mind for growers. Here’s what we learned. Read More
Crop Protection
February 27, 2017
New Discovery Smells Like Victory for Fl…
Scientists find naturally occurring repellent that could keep disease-carrying beetles at bay. Read More
Disease Control
February 23, 2017
Spot Sclerotinia Before It Stops Your Ve…
Learn how to identify, the survival and spread, as well as management methods for this malady that goes by many names. Read More
Crop Protection
January 31, 2017
Defend Your Cole Crops from Three Critic…
Learn symptoms, causal agents, and control measures for black rot, Alternaria leaf spot, and downy mildew. Read More
Disease Control
January 20, 2017
Don’t Let Stemphylium Leaf Spot St…
Learn how to identify, the survival and spread, as well as management methods for this vegetable disease. Read More
Disease Control
January 19, 2017
Clues Found to Block Late Blight’s…
With food security at stake, breakthrough in genetic research could help prevent more strains of the deadly pathogen from entering the U.S. Read More
Crop Protection
January 4, 2017
New Potato Insecticide/Fungicide Seed Tr…
Syngenta’s CruiserMaxx Vibrance receives EPA registration. Read More
Cucurbits
December 22, 2016
Stay Alert to Anthracnose of Cucurbits
Learn how to identify, the survival and spread, as well as management methods for this destructive vegetable disease. Read More
Disease Control
December 21, 2016
Two Tips to Improve Your Potato Seed Sto…
High-quality seed stock with a guaranteed low incidence of disease is the first step to success. Read More
Cucurbits
December 20, 2016
3 New Fungicide Product Options for Vege…
Unique modes of action the main feature of modern chemistries. Read More