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Plant Pathology

Summary
Summary

The department is recognized as a national and international leader in many areas of plant pathology. The research programs focus on diseases caused by fastidious microorganisms, bacteria, fungi, and whitefly- and aphid-transmitted viruses. We are known for our research on diseases of diverse crops including citrus; vegetables such as tomato, pepper and cucurbits; ornamentals including foliage plants and flowering and woody ornamentals; field crops including soybean, peanut and sugarcane; and tropical fruits. Our strengths also include expertise in epidemiology, molecular biology of host-parasite interactions, biological control, and post-harvest diseases. Our faculty has also been very active in international programs as evidenced by the many collaborative efforts in Florida and outside the U.S.
--- About Plant Pathology, https://plantpath.ifas.ufl.edu/about-us/

Editorial Team

New and Revised Publications

thumbnail for publication: Field Guide to Hemp (Cannabis sativa) Diseases

Field Guide to Hemp (Cannabis sativa) Diseases

Kevin Korus, Wael Elwakil, Nicholas Dufault, and Zachary Eldred

Industrial hemp is Cannabis sativa that contains < 0.3% THC and can be legally grown with permits in Florida. The plant may be grown for flower, grain, or fiber production. Other than the lower THC levels, hemp is the same plant botanically as marijuana. Because this plant has long been on the Schedule 1 controlled substance list in the U.S. (United States), knowledge of pests and diseases is limited, and labelled control measures are almost non-existent. This publication provides information and general management recommendations for hemp diseases found in Florida. Management options are currently limited as there is a lack of resistant varieties and other management strategies for industrial hemp production.

thumbnail for publication: A Basic Guide to Mushrooms Commonly Encountered in Potted Plants in Florida

A Basic Guide to Mushrooms Commonly Encountered in Potted Plants in Florida

Elena Karlsen-Ayala, Romina Gazis, and Matthew E. Smith

Mushrooms growing in potting soil are a common problem reported in nursery production and in potted plants in the indoor and outdoor home landscape. Many of these fungi are saprotrophic and feed on the organic matter contained in the potting soil itself and/or in the mulch, which varies in composition but often contains tree bark, wood chips, pine straw, moss, or leaves. These fungi are not necessarily harmful to the plants, but fungal fruiting bodies can make plants unmarketable. Unknown fungi can also be concerning to retailers and homeowners because of potential toxicity to pets and children. The purpose of this publication is to provide homeowners and retail nursery growers with an overview of some of the most common mushroom-forming fungi found in potted plants and potting soils in Florida. We also provide cultural control recommendations to help prevent or reduce mushroom growth.

thumbnail for publication: Florida Plant Disease Management Guide: Guava (Psidium guajava)

Florida Plant Disease Management Guide: Guava (Psidium guajava)

Romina Gazis, Jonathan Crane, and Jeff Wasielewski

Guava is a popular subtropical fruit tree grown commercially in south Florida. Production is affected by multiple diseases of different origin. This guide provides information about the most common diseases, including disease biology and management. Written by Romina Gazis, Jonathan Crane, and Jeff Wasielewski, and published by the UF/IFAS Plant Pathology Department, revised April 2024.

thumbnail for publication: Sample Collection for Ganoderma Butt Rot of Palms

Sample Collection for Ganoderma Butt Rot of Palms

Braham Dhillon and Seemanti Chakrabarti

Palms are an integral part of the urban landscape in Florida. Ganoderma butt rot of palms, a disease caused by the wood-decaying white-rot fungus Ganoderma zonatum, is one of the major biotic concerns for the landscape industry. The lethal disease is prevalent across palm-growing regions in the US, and all palm species are believed to be susceptible to this fungus. It may take six months to a year for the diseased palm to die once the initial symptoms appear. But with the availability of a disease diagnostic assay, this fungal pathogen can be detected using saw dust samples collected from declining palms, several months before symptoms appear. Collect good quality samples by following these steps and understanding the caveats associated with each step.

thumbnail for publication: The Emergence of Fusarium oxysporum f. sp. apii Race 4 Causing Fusarium Wilt on Celery in South Florida

The Emergence of Fusarium oxysporum f. sp. apii Race 4 Causing Fusarium Wilt on Celery in South Florida

Larissa Carvalho Ferreira, Anna Mészáros, and Katia Viana Xavier

Celery (Apium graveolens L.) production in south Florida spans approximately 1,500 acres yearly. Fusarium wilt, caused by Fusarium oxysporum f. sp. apii (Foa) race 4, emerged as a significant threat to celery production in the Everglades Agricultural Area (EAA) in Florida in 2022. Since it was first reported in the United States in Michigan in 1914, Foa has evolved into four different pathogenic races. In 2013, race 4 was first reported in California, ?and since then, it has been causing substantial losses to celery growers. The first occurrence in south Florida is critically alarming because (1) race 4 is the most virulent among the four races, (2) there is a lack of effective chemical and varietal control options for EAA Florida growers, and (3) this pathogen can survive in the soil for many years. This publication provides novel information to growers, Extension agents, and crop consultants of the celery industry in Florida regarding disease identification and management. 

thumbnail for publication: Tar Spot of Maize in Florida

Tar Spot of Maize in Florida

Larissa Carvalho Ferreira, Vitor Augusto Silva de Moura, Marcio F. R. Resende, and Katia Viana Xavier

Tar spot, a fungal foliar disease, affects most maize types commonly grown in Florida, such as sweet corn, field corn, and criollo corn. This disease is characterized by brown-to-black, raised structures called stromata, which are embedded in leaf tissue. As a polycyclic disease, tar spot lesions can increase in number as the disease progresses throughout the growing season, leading to reduction of photosynthetic area on the leaves. Tar spot has recently emerged as a significant threat in Florida and in the United States, with reports of up to 100% incidence in maize fields in south Florida. Tar spot occurrence and development in Florida is influenced by several factors, such as environmental conditions, maize types, crop maintenance, and corn growth stages. The purpose of this publication is to promote awareness among Florida growers regarding this newly identified disease and its management practices.

thumbnail for publication: Bacterial Leaf Spot of Cucurbits

Bacterial Leaf Spot of Cucurbits

Kiersten Fullem, Mathews L. Paret, and Jeffrey B. Jones

This publication is intended to provide information on the disease bacterial leaf spot of cucurbits, its epidemiology, and management to cucurbit growers in the southeastern United States. Written by Kiersten Fullem, Mathews L. Paret, and Jeffrey B. Jones, and published by the UF/IFAS Plant Pathology Department, March 2024.

thumbnail for publication: Citrus Canker and Citrus Leprosis Fruit Symptom Comparison

Citrus Canker and Citrus Leprosis Fruit Symptom Comparison

A. Levy, J. D. Burrow, and M. M. Dewdney

This publication is intended to guide citrus growers in distinguishing the difference between citrus canker and citrus leprosis. 

thumbnail for publication: Recolección de muestras de pudrición basal de las palmas causada por Ganoderma

Recolección de muestras de pudrición basal de las palmas causada por Ganoderma

Braham Dhillon y Seemanti Chakrabarti

Las palmeras son una parte integral del paisaje urbano de Florida. La pudrición de las palmas por Ganoderma, una enfermedad causada por el hongo Ganoderma zonatum, que descompone la madera, es una de las principales preocupaciones bióticas para la industria del paisajismo. La enfermedad letal prevalece en las regiones de cultivo de palmeras en los EE. UU., y se cree que todas las especies de palmeras son susceptibles a este hongo. La palma enferma puede tardar entre seis meses y un año en morir una vez que aparecen los síntomas iniciales. Pero con la disponibilidad de un ensayo de diagnóstico de enfermedades, este patógeno fúngico se puede detectar utilizando muestras de aserrín recogidas de palmas en declive, varios meses antes de que aparezcan los síntomas. Aquí se indican los pasos a seguir.

thumbnail for publication: Marasmius vagus (the Wandering Creamsicle), One of Florida’s Most Common Lawn Mushrooms

Marasmius vagus (the Wandering Creamsicle), One of Florida’s Most Common Lawn Mushrooms

Sarah Prentice and Matthew E. Smith

Marasmius vagus is one of the most common lawn mushrooms in the state of Florida. The purpose of this publication is to introduce Floridians to this mushroom, provide basic information about its biology, and aid in identification. Written by Sarah Prentice and Matthew E. Smith, and published by the UF/IFAS Plant Pathology Department, February 2024.

The department is recognized as a national and international leader in many areas of plant pathology. The research programs focus on diseases caused by fastidious microorganisms, bacteria, fungi, and whitefly- and aphid-transmitted viruses. We are known for our research on diseases of diverse crops including citrus; vegetables such as tomato, pepper and cucurbits; ornamentals including foliage plants and flowering and woody ornamentals; field crops including soybean, peanut and sugarcane; and tropical fruits. Our strengths also include expertise in epidemiology, molecular biology of host-parasite interactions, biological control, and post-harvest diseases. Our faculty has also been very active in international programs as evidenced by the many collaborative efforts in Florida and outside the U.S.
--- About Plant Pathology, https://plantpath.ifas.ufl.edu/about-us/

Editorial Team

New and Revised Publications

thumbnail for publication: Field Guide to Hemp (Cannabis sativa) Diseases

Field Guide to Hemp (Cannabis sativa) Diseases

Kevin Korus, Wael Elwakil, Nicholas Dufault, and Zachary Eldred

Industrial hemp is Cannabis sativa that contains < 0.3% THC and can be legally grown with permits in Florida. The plant may be grown for flower, grain, or fiber production. Other than the lower THC levels, hemp is the same plant botanically as marijuana. Because this plant has long been on the Schedule 1 controlled substance list in the U.S. (United States), knowledge of pests and diseases is limited, and labelled control measures are almost non-existent. This publication provides information and general management recommendations for hemp diseases found in Florida. Management options are currently limited as there is a lack of resistant varieties and other management strategies for industrial hemp production.

thumbnail for publication: A Basic Guide to Mushrooms Commonly Encountered in Potted Plants in Florida

A Basic Guide to Mushrooms Commonly Encountered in Potted Plants in Florida

Elena Karlsen-Ayala, Romina Gazis, and Matthew E. Smith

Mushrooms growing in potting soil are a common problem reported in nursery production and in potted plants in the indoor and outdoor home landscape. Many of these fungi are saprotrophic and feed on the organic matter contained in the potting soil itself and/or in the mulch, which varies in composition but often contains tree bark, wood chips, pine straw, moss, or leaves. These fungi are not necessarily harmful to the plants, but fungal fruiting bodies can make plants unmarketable. Unknown fungi can also be concerning to retailers and homeowners because of potential toxicity to pets and children. The purpose of this publication is to provide homeowners and retail nursery growers with an overview of some of the most common mushroom-forming fungi found in potted plants and potting soils in Florida. We also provide cultural control recommendations to help prevent or reduce mushroom growth.

thumbnail for publication: Florida Plant Disease Management Guide: Guava (Psidium guajava)

Florida Plant Disease Management Guide: Guava (Psidium guajava)

Romina Gazis, Jonathan Crane, and Jeff Wasielewski

Guava is a popular subtropical fruit tree grown commercially in south Florida. Production is affected by multiple diseases of different origin. This guide provides information about the most common diseases, including disease biology and management. Written by Romina Gazis, Jonathan Crane, and Jeff Wasielewski, and published by the UF/IFAS Plant Pathology Department, revised April 2024.

thumbnail for publication: Sample Collection for Ganoderma Butt Rot of Palms

Sample Collection for Ganoderma Butt Rot of Palms

Braham Dhillon and Seemanti Chakrabarti

Palms are an integral part of the urban landscape in Florida. Ganoderma butt rot of palms, a disease caused by the wood-decaying white-rot fungus Ganoderma zonatum, is one of the major biotic concerns for the landscape industry. The lethal disease is prevalent across palm-growing regions in the US, and all palm species are believed to be susceptible to this fungus. It may take six months to a year for the diseased palm to die once the initial symptoms appear. But with the availability of a disease diagnostic assay, this fungal pathogen can be detected using saw dust samples collected from declining palms, several months before symptoms appear. Collect good quality samples by following these steps and understanding the caveats associated with each step.

thumbnail for publication: The Emergence of Fusarium oxysporum f. sp. apii Race 4 Causing Fusarium Wilt on Celery in South Florida

The Emergence of Fusarium oxysporum f. sp. apii Race 4 Causing Fusarium Wilt on Celery in South Florida

Larissa Carvalho Ferreira, Anna Mészáros, and Katia Viana Xavier

Celery (Apium graveolens L.) production in south Florida spans approximately 1,500 acres yearly. Fusarium wilt, caused by Fusarium oxysporum f. sp. apii (Foa) race 4, emerged as a significant threat to celery production in the Everglades Agricultural Area (EAA) in Florida in 2022. Since it was first reported in the United States in Michigan in 1914, Foa has evolved into four different pathogenic races. In 2013, race 4 was first reported in California, ?and since then, it has been causing substantial losses to celery growers. The first occurrence in south Florida is critically alarming because (1) race 4 is the most virulent among the four races, (2) there is a lack of effective chemical and varietal control options for EAA Florida growers, and (3) this pathogen can survive in the soil for many years. This publication provides novel information to growers, Extension agents, and crop consultants of the celery industry in Florida regarding disease identification and management. 

thumbnail for publication: Tar Spot of Maize in Florida

Tar Spot of Maize in Florida

Larissa Carvalho Ferreira, Vitor Augusto Silva de Moura, Marcio F. R. Resende, and Katia Viana Xavier

Tar spot, a fungal foliar disease, affects most maize types commonly grown in Florida, such as sweet corn, field corn, and criollo corn. This disease is characterized by brown-to-black, raised structures called stromata, which are embedded in leaf tissue. As a polycyclic disease, tar spot lesions can increase in number as the disease progresses throughout the growing season, leading to reduction of photosynthetic area on the leaves. Tar spot has recently emerged as a significant threat in Florida and in the United States, with reports of up to 100% incidence in maize fields in south Florida. Tar spot occurrence and development in Florida is influenced by several factors, such as environmental conditions, maize types, crop maintenance, and corn growth stages. The purpose of this publication is to promote awareness among Florida growers regarding this newly identified disease and its management practices.

thumbnail for publication: Bacterial Leaf Spot of Cucurbits

Bacterial Leaf Spot of Cucurbits

Kiersten Fullem, Mathews L. Paret, and Jeffrey B. Jones

This publication is intended to provide information on the disease bacterial leaf spot of cucurbits, its epidemiology, and management to cucurbit growers in the southeastern United States. Written by Kiersten Fullem, Mathews L. Paret, and Jeffrey B. Jones, and published by the UF/IFAS Plant Pathology Department, March 2024.

thumbnail for publication: Citrus Canker and Citrus Leprosis Fruit Symptom Comparison

Citrus Canker and Citrus Leprosis Fruit Symptom Comparison

A. Levy, J. D. Burrow, and M. M. Dewdney

This publication is intended to guide citrus growers in distinguishing the difference between citrus canker and citrus leprosis. 

thumbnail for publication: Recolección de muestras de pudrición basal de las palmas causada por Ganoderma

Recolección de muestras de pudrición basal de las palmas causada por Ganoderma

Braham Dhillon y Seemanti Chakrabarti

Las palmeras son una parte integral del paisaje urbano de Florida. La pudrición de las palmas por Ganoderma, una enfermedad causada por el hongo Ganoderma zonatum, que descompone la madera, es una de las principales preocupaciones bióticas para la industria del paisajismo. La enfermedad letal prevalece en las regiones de cultivo de palmeras en los EE. UU., y se cree que todas las especies de palmeras son susceptibles a este hongo. La palma enferma puede tardar entre seis meses y un año en morir una vez que aparecen los síntomas iniciales. Pero con la disponibilidad de un ensayo de diagnóstico de enfermedades, este patógeno fúngico se puede detectar utilizando muestras de aserrín recogidas de palmas en declive, varios meses antes de que aparezcan los síntomas. Aquí se indican los pasos a seguir.

thumbnail for publication: Marasmius vagus (the Wandering Creamsicle), One of Florida’s Most Common Lawn Mushrooms

Marasmius vagus (the Wandering Creamsicle), One of Florida’s Most Common Lawn Mushrooms

Sarah Prentice and Matthew E. Smith

Marasmius vagus is one of the most common lawn mushrooms in the state of Florida. The purpose of this publication is to introduce Floridians to this mushroom, provide basic information about its biology, and aid in identification. Written by Sarah Prentice and Matthew E. Smith, and published by the UF/IFAS Plant Pathology Department, February 2024.

Showing 100 of 142 Publications

"Candidatus Liberibacter solanacearum": An Emerging Pathogen Infecting Potato and Tomato

Binoy Babu, Mathews L. Paret, Nicholas Dufault, and Carrie L. Harmon

thumbnail for publication: 2024–2025 Florida Citrus Production Guide: Alternaria Brown Spot

2024–2025 Florida Citrus Production Guide: Alternaria Brown Spot

Megan M. Dewdney

2024-2025 Florida Citrus Production Guide

thumbnail for publication: 2024–2025 Florida Citrus Production Guide: Citrus Black Spot

2024–2025 Florida Citrus Production Guide: Citrus Black Spot

Megan M. Dewdney, Callie Walker, Pamela D. Roberts, and Natalia A. Peres

2024–2025 Florida Citrus Production Guide

thumbnail for publication: 2024–2025 Florida Citrus Production Guide: Exocortis, Cachexia, and Other Viroids

2024–2025 Florida Citrus Production Guide: Exocortis, Cachexia, and Other Viroids

Amit Levy, Ozgur Batuman, and Ronald H. Brlansky

2024-2025 Florida Citrus Production Guide

thumbnail for publication: 2024–2025 Florida Citrus Production Guide: Introduction

2024–2025 Florida Citrus Production Guide: Introduction

Lauren M. Diepenbrock, Megan M. Dewdney, and Tripti Vashisth

2024–2025 Florida Citrus Production Guide

thumbnail for publication: 2024–2025 Florida Citrus Production Guide: Postbloom Fruit Drop

2024–2025 Florida Citrus Production Guide: Postbloom Fruit Drop

Natalia A. Peres and Megan M. Dewdney

2024-2025 Florida Citrus Production Guide

thumbnail for publication: A Basic Guide to Mushrooms Commonly Encountered in Potted Plants in Florida

A Basic Guide to Mushrooms Commonly Encountered in Potted Plants in Florida

Elena Karlsen-Ayala, Romina Gazis, and Matthew E. Smith

Mushrooms growing in potting soil are a common problem reported in nursery production and in potted plants in the indoor and outdoor home landscape. Many of these fungi are saprotrophic and feed on the organic matter contained in the potting soil itself and/or in the mulch, which varies in composition but often contains tree bark, wood chips, pine straw, moss, or leaves. These fungi are not necessarily harmful to the plants, but fungal fruiting bodies can make plants unmarketable. Unknown fungi can also be concerning to retailers and homeowners because of potential toxicity to pets and children. The purpose of this publication is to provide homeowners and retail nursery growers with an overview of some of the most common mushroom-forming fungi found in potted plants and potting soils in Florida. We also provide cultural control recommendations to help prevent or reduce mushroom growth.

Angular Leaf Spot of Strawberry

Natalia A. Peres and Leandro G. Cordova

A UF/IFAS numbered Fact Sheet.

Anthracnose on Cucurbits in Florida

Pamela D. Roberts, Gary Vallad, Shouan Zhang, Nicholas Dufault, and Mathews Paret

Watermelon (Citrullus lanatus), cantaloupe or muskmelon (Cucumis melo), squash (Cucurbita pepo), bitter gourd (Momordica charantia), and cucumber (Cucumis sativa) are commonly grown throughout Florida on both commercial farms and home gardens, while pumpkin (Cucurbita maxima) production is largely limited to north Florida.  Anthracnose on cucurbits, caused by the fungus Colletotrichum orbiculare, is a common disease that occurs worldwide and throughout Florida. While all cucurbits are susceptible to the disease, cucumber, cantaloupe, and watermelon are most frequently affected. This EDIS document provides information regarding the pathogen, disease cycle, diagnostics and symptoms, and an overview of management of this disease on cucucurbits.

Anthurium Diseases: Identification and Control in Commercial Greenhouse Operations

David J. Norman and Gul Shad Ali

thumbnail for publication: Bacterial Speck of Tomato

Bacterial Speck of Tomato

Shouan Zhang, Geoffrey Meru, and Ken Pernezny

A UF/IFAS numbered Fact Sheet.

Bird's Nest Fungi: Charismatic Mushrooms in Your Garden

Nattapol Kraisitudomsook and Matthew E. Smith

Botryosphaeria Stem Blight on Southern Highbush Blueberry in Florida

Norma C. Flor, Douglas A. Phillips, and Philip F. Harmon

Stem blight is the most common disease that kills our blueberry bushes in Florida. In most cases, stem blight finishes the job, but other stresses play a lead or contributory role. When stem blight starts showing up in a production field, first check for all of the above discussed stressors, diseases, and pests. Once identified, developing an integrated and comprehensive disease management plan will help you stay one step ahead of stem blight.

thumbnail for publication: Calonectria (Cylindrocladium) Leaf Spot of Palm

Calonectria (Cylindrocladium) Leaf Spot of Palm

Jiaming Yu and Monica L. Elliott

Charcoal Rot of Strawberry Caused by Macrophomina phaseolina

N. A. Peres, J. S. Baggio, and J. C. Mertely

A UF/IFAS numbered Fact Sheet for Commercial audience(s). in support of UF/IFAS Extension program: Integrated Pest Management

thumbnail for publication: Citrus Canker and Citrus Leprosis Fruit Symptom Comparison

Citrus Canker and Citrus Leprosis Fruit Symptom Comparison

A. Levy, J. D. Burrow, and M. M. Dewdney

This publication is intended to guide citrus growers in distinguishing the difference between citrus canker and citrus leprosis. 

Citrus Diseases Exotic to Florida: Citrus Leprosis

O. Batuman, A. Levy, P. Sieburth, A. M. Paolillo, K.-R. Chung, and R. H. Brlansky

Common Bacterial Blight of Snap Bean in Florida

Shouan Zhang, Geoffrey Meru, Aaron J. Palmateer, Ken Pernezny, and Jeffrey B. Jones

A UF/IFAS numbered Fact Sheet.

Dieffenbachia Diseases: Identification and Control in Commercial Greenhouse Operations

David Norman

This article provides guidelines to identify and treat diseases that may be encountered during the commercial production of Dieffenbachia. This document is PP286, one of a series of the Plant Pathology Department, UF/IFAS Extension. Original publication date October 2011.

Diseases of Bitter Melon in South Florida

Shouan Zhang, Nicholas Dufault, Qingren Wang, Guodong Liu, and Gene McAvoy

Enfermedades Exóticas De Los Cítricos

Megan M. Dewdney, Jamie D. Burrow, Michael E. Rogers, and Timothy M. Spann

A UF/IFAS numbered Translation.

Fairy Rings

M. L. Elliott and P. F. Harmon

Florida Plant Disease Management Guide: Beans

Shouan Zhang, Geoffrey Meru, Aaron Palmateer, and Ken Pernezny

This fact sheet summarizes specific common diseases of beans, briefly describing symptoms and cultural controls. This edition is an update and revision with Geoffrey Meru as an added co-author.

thumbnail for publication: Fusarium Crown and Root Rot of Tomato in Florida

Fusarium Crown and Root Rot of Tomato in Florida

Shouan Zhang, Pamela D. Roberts, Geoffrey Meru, Robert J. McGovern, and Lawrence E. Datnoff

A UF/IFAS numbered Management for Commercial audience(s).

thumbnail for publication: Fusarium Wilt of Queen Palm and Mexican Fan Palm

Fusarium Wilt of Queen Palm and Mexican Fan Palm

Monica L. Elliott

This document is PP278, one of a series of the Plant Pathology Department, UF/IFAS Extension. Original publication date June 2010. Revised August 2013 and January 2017.

Homeowner's Guide to Fungicides for Lawn and Landscape Disease Management

Philip Harmon and Aaron Palmateer

Impatiens Downy Mildew

N. A. Peres and L. A. Warner

Downy mildew on impatiens is of great concern throughout Florida. Winters in south Florida provide high humidity paired with cool nights, creating ideal conditions for disease development. Downy mildews are caused by several different species of pathogens that tend to be plant-host specific. Plasmopara obducens is the pathogen that affects impatiens. Some literature indicates that nighttime temperatures of about 50°F to 72°F favor downy mildew, but the disease has been reported on impatiens year-round in south Florida.

Introducing a Fusarium Wilt Risk Calculator Tool for Watermelon Growers in Florida

Matthew Cullen, Daniel Perondi, Clyde Fraisse, and Nicholas Dufault

Fusarium wilt of watermelon, caused by the fungus Fusarium oxysporum f. sp. niveum, is a threat to watermelon production in Florida. While a number of management options are available, numerous factors influence which management strategies are feasible for growers. This new 4-page publication of the UF/IFAS Plant Pathology Department introduces a tool that calculates the estimated risk of Fusarium wilt based on potential management strategies and environmental factors. This tool is intended for use by watermelon growers in Florida and should be helpful in advising them on management decisions. Written by Matthew Cullen, Daniel Perondi, Clyde Fraisse, and Nicholas Dufault.

Late Blight on Potato and Tomato

Pamela Roberts and Ryan Donahoo

This document is PP301, one of a series of the Department of Plant Pathology, UF/IFAS Extension. Original publication date December 2012. Revised May 2016.

Lethal Yellowing (LY) of Palm

Brian W. Bahder and Ericka E. Helmick

thumbnail for publication: Management of Gummy Stem Blight (Black Rot) on Cucurbits in Florida

Management of Gummy Stem Blight (Black Rot) on Cucurbits in Florida

Mathews L. Paret, Nicholas S. Dufault, Mason Newark, and Joshua H. Freeman

Gummy stem blight (GSB) is a major disease of many cucurbits, including watermelon, cantaloupe, cucumber, pumpkin, squash, muskmelon, and other melons. The disease is also known as black rot due to its characteristic appearance on infected fruits. Learn the symptoms, causal agent and disease spread, and fungicides labeled for use in Florida.

thumbnail for publication: Marasmius vagus (the Wandering Creamsicle), One of Florida’s Most Common Lawn Mushrooms

Marasmius vagus (the Wandering Creamsicle), One of Florida’s Most Common Lawn Mushrooms

Sarah Prentice and Matthew E. Smith

Marasmius vagus is one of the most common lawn mushrooms in the state of Florida. The purpose of this publication is to introduce Floridians to this mushroom, provide basic information about its biology, and aid in identification. Written by Sarah Prentice and Matthew E. Smith, and published by the UF/IFAS Plant Pathology Department, February 2024.

thumbnail for publication: Palm Problems: Field and Laboratory Diagnosis

Palm Problems: Field and Laboratory Diagnosis

Monica L. Elliott and Timothy K. Broschat

PP-246, a 6-page illustrated fact sheet by Monica L. Elliott and Timothy K. Broschat, includes tips to determine when laboratory diagnostics may be useful and how to interpret and/or integrate field and laboratory diagnoses. Includes references.

thumbnail for publication: Pest Management of Peppers in Miami-Dade County, Florida

Pest Management of Peppers in Miami-Dade County, Florida

Qingren Wang, Shouan Zhang, Dakshina Seal, and Teresa Olczyk

To assist local pepper growers in maintaining crop productivity and improving the quality of produce, this publication illustrates common pests including major diseases and insects and their effective management. The targeted audiences are pepper growers, pest control operators, extension agents and specialists, crop advisors, industrial personnel, and graduate students. A minor revision of the UF/IFAS Plant Pathology Department, written by Q. Wang, S. Zhang, D. Seal, and T. Olczyk; 8 pp.

2018 Florida Plant Disease Management Guide: Watermelon

Pamela D. Roberts

thumbnail for publication: 2024–2025 Florida Citrus Production Guide: Blight

2024–2025 Florida Citrus Production Guide: Blight

Ozgur Batuman, Amit Levy, and Ronald H. Brlansky

2024-2025 Florida Citrus Production Guide

thumbnail for publication: 2024–2025 Florida Citrus Production Guide: Citrus Canker

2024–2025 Florida Citrus Production Guide: Citrus Canker

Megan M. Dewdney and Evan G. Johnson

2024–2025 Florida Citrus Production Guide

thumbnail for publication: 2024–2025 Florida Citrus Production Guide: Greasy Spot

2024–2025 Florida Citrus Production Guide: Greasy Spot

Megan M. Dewdney

2024-2025 Florida Citrus Production Guide

thumbnail for publication: 2024–2025 Florida Citrus Production Guide: Melanose

2024–2025 Florida Citrus Production Guide: Melanose

Megan M. Dewdney

2024-2025 Florida Citrus Production Guide

thumbnail for publication: 2024–2025 Florida Citrus Production Guide: Tristeza Decline

2024–2025 Florida Citrus Production Guide: Tristeza Decline

Ozgur Batuman, Amit Levy, Mark E. Hilf, Peggy J. Sieburth, Ronald H. Brlansky, and William O. Dawson

2024-2025 Florida Citrus Production Guide

A Postharvest Fruit Rot Caused by Alternaria sp. on Imported Plum Tomatoes in South Florida

Zelalem Mersha, Shouan Zhang, and Jerry A. Bartz

Anthracnose

M. L. Elliott and P. F. Harmon

Anthracnose on Pepper in Florida

P. D. Roberts, K. L. Pernezny, and T. A. Kucharek

thumbnail for publication: Bacterial Blight of Ficus Caused by Xanthomonas

Bacterial Blight of Ficus Caused by Xanthomonas

Romina Gazis, Vanessa Campoverde and Aaron Palmateer

A UF/IFAS numbered Fact Sheet for Commercial audience(s). Published by Integrated Pest Management

Bacterial Spot of Pepper

Camille McAvoy, Pamela Roberts, and Jeffrey Jones

Black Spot of Rose

Jozer Mangandi and Natalia A. Peres

Botrytis Blossom Blight of Southern Highbush Blueberry

Philip F. Harmon

Cercospora Leaf Spot

M. L. Elliott and P. F. Harmon

Chicken of the Woods (Laetiporus sulphureus species complex)

Brianna Benitez, Claudia A. Paez, Matthew E. Smith, and Jason A. Smith

Citrus Canker Symptoms on Nursery Trees

Timothy D. Riley, Megan M. Dewdney, and Jamie D. Burrow

A UF/IFAS numbered Fact Sheet for Commercial audience(s).

Citrus Leprosis Fruit, Leaf, and Stem Symptom Identification

Amit Levy, Ozgur Batuman, Megan M. Dewdney, and Jamie D. Burrow

This new two-page handout provides a brief summary of citrus leprosis symptoms. Written by Amit Levy, Ozgur Batuman, Megan M. Dewdney, and Jamie D. Burrow and published by the UF/IFAS Plant Pathology Department.

Common Strawberry Diseases in Florida

Michelle S. Oliveira and Natalia A. Peres

This publication describes symptoms of most common strawberry diseases in Florida and summarizes the efficacy of fungicides labeled for management of such diseases.

thumbnail for publication: Disease Control for Florida Tomatoes

Disease Control for Florida Tomatoes

Shouan Zhang, Mathews Paret, Ken Pernezny, and Pamela Roberts

Successful disease management has always been vital in Florida tomato production, given the generally ideal environmental conditions for most plant diseases. An integrated disease management program is a successful approach.

Diseases of Pomegranate (Punica granatum) in Florida

Katia V. Xavier, Achala N. KC, and Gary E. Vallad

Pomegranate production is becoming increasingly popular in the Southeast. Florida’s humid subtropical to tropical climate is favorable for not only pomegranate tree establishment, but also several diseases. This publication describes the various diseases affecting pomegranate in Florida and provides some management recommendations.

Enfermedades fúngicas foliares de los cítricos para los patios y zonas residenciales

Megan M. Dewdney y Jamie D. Burrow

Este documento es una hoja de dos páginas ilustrativas para la identificación de las enfermedades fúngicas foliares de los cítricos. A UF/IFAS numbered Translation. Minor revision by Megan M. Dewdney and Jamie D. Burrow, Plant Pathology Department; 2 pages.

thumbnail for publication: Field Guide to Hemp (Cannabis sativa) Diseases

Field Guide to Hemp (Cannabis sativa) Diseases

Kevin Korus, Wael Elwakil, Nicholas Dufault, and Zachary Eldred

Industrial hemp is Cannabis sativa that contains < 0.3% THC and can be legally grown with permits in Florida. The plant may be grown for flower, grain, or fiber production. Other than the lower THC levels, hemp is the same plant botanically as marijuana. Because this plant has long been on the Schedule 1 controlled substance list in the U.S. (United States), knowledge of pests and diseases is limited, and labelled control measures are almost non-existent. This publication provides information and general management recommendations for hemp diseases found in Florida. Management options are currently limited as there is a lack of resistant varieties and other management strategies for industrial hemp production.

thumbnail for publication: Florida Plant Disease Management Guide: Guava (Psidium guajava)

Florida Plant Disease Management Guide: Guava (Psidium guajava)

Romina Gazis, Jonathan Crane, and Jeff Wasielewski

Guava is a popular subtropical fruit tree grown commercially in south Florida. Production is affected by multiple diseases of different origin. This guide provides information about the most common diseases, including disease biology and management. Written by Romina Gazis, Jonathan Crane, and Jeff Wasielewski, and published by the UF/IFAS Plant Pathology Department, revised April 2024.

Fusarium Wilt (Fusarium oxysporum f. sp. niveum) of Watermelon

Pamela Roberts, Nicholas Dufault, Robert Hochmuth, Gary Vallad, and Mathews Paret

A UF/IFAS numbered Fact Sheet for Commercial audience(s). in support of UF/IFAS Extension program: Integrated Pest Management

Gray Leaf Spot of St. Augustinegrass: Cultural and Chemical Management Options

Philip Harmon

thumbnail for publication: Huanglongbing (HLB; Citrus Greening) and Nutrient Deficiency Identification

Huanglongbing (HLB; Citrus Greening) and Nutrient Deficiency Identification

Tripti Vashisth, Megan M. Dewdney, and Jamie D. Burrow

Huanglongbing (HLB) is a bacterial disease that is spread by an insect, the Asian citrus psyllid. This 2-page fact sheet explains how to tell the difference between HLB symptoms and symptoms from nutrient deficiencies.

Integrated Disease Management for Vegetable Crops in Florida

Mathews Paret, Nick Dufault, Tim Momol, Jim Marois, and Steve Olson

Integrated Pest Management (IPM) as applied to vegetable diseases means using all the tactics available to the grower (cultural, biological, host-plant resistance, field scouting, chemical) that provide acceptable yield and quality at the least cost and are compatible with the tenets of environmental stewardship. This 6-page fact sheet was written by Mathews Paret, Nick Dufault, Tim Momol, Jim Marois, and Steve Olson, and published by the UF Department of Plant Pathology, August 2012.

thumbnail for publication: Key for Identification of Landscape Turfgrass Diseases

Key for Identification of Landscape Turfgrass Diseases

P. F. Harmon and M. L. Elliott

Leaf Spot Diseases of Strawberry

Juliana S. Baggio, James C. Mertely, and Natalia A. Peres

Macrocybe titans: The Mushroom Giant of the Western Hemisphere

Elena Karlsen-Ayala and Matthew E. Smith

Management of Powdery Mildew in Beans

Qingren Wang, Shouan Zhang, and Teresa Olczyk

Powdery mildew is one of the most commonly occurring diseases on many types of beans. Although the causal organism rarely causes extensive damage, significant yield losses were reported in Columbia County when infection occurred in dry beans prior to flowering. Accurately identifying this disease and immediately taking action for control are critical to effectively prevent spread of powdery mildew in order to reduce significant losses of yield and quality.

Mosaic Disease of St. Augustinegrass Caused by Sugarcane Mosaic Virus

Phil Harmon

thumbnail for publication: Pepper Mild Mottle Virus

Pepper Mild Mottle Virus

Pamela D. Roberts and Scott Adkins

2021 Florida Plant Disease Management Guide: Eggplant

Shouan Zhang, Geoffrey Meru, Ken Pernezny, and Aaron Palmateer

A UF/IFAS numbered Management.

thumbnail for publication: 2024–2025 Florida Citrus Production Guide: Brown Rot of Fruit

2024–2025 Florida Citrus Production Guide: Brown Rot of Fruit

Megan M. Dewdney and Evan G. Johnson

2024–2025 Florida Citrus Production Guide

thumbnail for publication: 2024–2025 Florida Citrus Production Guide: Citrus Scab

2024–2025 Florida Citrus Production Guide: Citrus Scab

Megan M. Dewdney

2024–2025 Florida Citrus Production Guide

thumbnail for publication: 2024–2025 Florida Citrus Production Guide: Huanglongbing (Citrus Greening)

2024–2025 Florida Citrus Production Guide: Huanglongbing (Citrus Greening)

Megan M. Dewdney, Tripti Vashisth, and Lauren M. Diepenbrock

2023–2024 Florida Citrus Production Guide

thumbnail for publication: 2024–2025 Florida Citrus Production Guide: Phytophthora Foot Rot, Crown Rot, and Root Rot

2024–2025 Florida Citrus Production Guide: Phytophthora Foot Rot, Crown Rot, and Root Rot

Megan M. Dewdney and Evan G. Johnson

2024-2025 Florida Citrus Production Guide

thumbnail for publication: 2024–2025 Quick Reference Guide for Foliar Fungicides

2024–2025 Quick Reference Guide for Foliar Fungicides

Megan M. Dewdney

A UF/IFAS numbered Fact Sheet for Commercial audience(s).

Algal Stem Blotch in Southern Highbush Blueberry in Florida

Douglas Phillips, Norma Flor, and Phillip Harmon

Anthracnose Fruit Rot of Strawberry

James C. Mertely, Bruna B. Forcelini, and Natalia. A. Peres

A UF/IFAS numbered Fact Sheet.

Anthracnose on Southern Highbush Blueberry

Douglas A. Phillips, Maria C. Velez-Climent, Philip F. Harmon, and Patricio R. Munoz

thumbnail for publication: Bacterial Leaf Spot of Cucurbits

Bacterial Leaf Spot of Cucurbits

Kiersten Fullem, Mathews L. Paret, and Jeffrey B. Jones

This publication is intended to provide information on the disease bacterial leaf spot of cucurbits, its epidemiology, and management to cucurbit growers in the southeastern United States. Written by Kiersten Fullem, Mathews L. Paret, and Jeffrey B. Jones, and published by the UF/IFAS Plant Pathology Department, March 2024.

Bacterial Wilt of Southern Highbush Blueberry Caused by Ralstonia solanacearum

Philip F. Harmon, Carrie Harmon, and Dave Norman

Blueberry Advisory System: A Disease Alert System for Blueberry Anthracnose Fruit Rot

André B. Gama, Douglas A. Phillips, Vinícius A. Cerbaro, Phillip F. Harmon, Clyde W. Fraisse, and Natalia A. Peres

The weather conditions favoring Blueberry anthracnose fruit rot disease incidence and development can be difficult to predict, and it can significantly impact yield under conducive weather patterns. For that reason, the authors of this new 6-page publication of the UF/IFAS Plant Pathology Department developed and validated a web-based disease alert system for blueberry AFR, the Blueberry Advisory System (BAS), to help blueberry growers in Florida identify weather conditions favorable for the disease and improve disease management. Written by André B. Gama, Douglas A. Phillips, Vinícius A. Cerbaro, Phillip F. Harmon, Clyde W. Fraisse, and Natalia A. Peres.

Botrytis Fruit Rot or Gray Mold of Strawberry

J.C. Mertely, M. S. Oliveira, and N. A. Peres

A UF/IFAS numbered Fact Sheet. in support of UF/IFAS Extension program: Integrated Pest Management

Cercospora Leaf Spot of Rose

Jozer Mangandi and Natalia A. Peres

Citrus Black Spot

Megan M. Dewdney and Natalia A. Peres

A UF/IFAS numbered Fact Sheet.

Citrus Disease Identification Chart

Amit Levy, Jamie D. Burrow, and Megan M. Dewdney

This flowchart is intended to help both commercial citrus growers and home gardeners in properly identifying common citrus diseases on fruit, leaves, and stems. Proper identification will help determine the appropriate management strategy. Written by Amit Levy, Jamie D. Burrow, and Megan M. Dewdney, and published by the UF/IFAS Plant Pathology Department.

Colletotrichum Crown Rot (Anthracnose Crown Rot) of Strawberry

Natalia A. Peres, M. S. Oliveira, and Steven J. MacKenzie

A UF/IFAS numbered Fact Sheet.

Common Tomato High-Tunnel Production Diseases in Florida

Zachary D. Eldred, Shufang Tian, Gary E. Vallad, Xin Zhao, Mathews Paret, and Nicholas S. Dufault

This new 7-page article provides a concise overview of some influential high-tunnel tomato soilborne and foliar diseases and their cultural management techniques. Written by Zachary D. Eldred, Shufang Tian, Gary E. Vallad, Xin Zhao, Mathews Paret, and Nicholas S. Dufault and published by the UF/IFAS Plant Pathology Department.

Disease Control for Snap Beans in Florida

Shouan Zhang, Nicholas Dufault, Mathews Paret, Pamela Roberts, Guodong Liu, and Qingren Wang

This publication suggests a sequential disease control program for snap beans in Florida. Postharvest disease problems are addressed only to the extent that they are affected by field practices. The application of the following sequential control program should minimize yield losses for the majority of plantings.

Downy Mildew of Basil in South Florida

Shouan Zhang, Jaimin S. Patel, Zelalem Mersha, Pamela D. Roberts, and Richard Raid

English Ivy (Hedera helix): Identification and Control of Diseases in Commercial Greenhouse Production and in Landscapes

David J. Norman and G. Shad Ali

Florida Blueberry Leaf Disease Guide

Douglas A. Phillips, Norma C. Flor, and Philip F. Harmon

thumbnail for publication: Florida Plant Disease Management Guide: Sweet Basil

Florida Plant Disease Management Guide: Sweet Basil

Shouan Zhang, Geoffrey Meru, and Pamela D. Roberts

A UF/IFAS numbered Management.

thumbnail for publication: Fusarium Wilt of Canary Island Date Palm

Fusarium Wilt of Canary Island Date Palm

Monica L. Elliott

Helminthosporium Leaf Spot

M. L. Elliott and P. F. Harmon

Identification of Early Citrus Black Spot Symptoms (Identificacíon de los Síntomas Iniciales de la Mancha Negra de los Cítricos)

Megan M. Dewdney, J. D. Burrow, and Mark A. Ritenour

thumbnail for publication: Integrated Management of Bacterial Spot on Tomato in Florida

Integrated Management of Bacterial Spot on Tomato in Florida

Amanda Strayer-Scherer, Ying-Yu Liao, Peter Abrahamian, Sujan Timilsina, Mathews Paret, Tim Momol, Jeff Jones, and Gary Vallad

Bacterial spot is one of the most detrimental diseases of tomato and is especially severe in the southeast United States when weather conditions (high temperature, high humidity, and rain) become conducive for disease development. This publication presents updated information about the causal pathogen and management of bacterial spot on tomato in Florida.

Large Patch

M. L. Elliott and P. F. Harmon

Lethal Bronzing Disease (LB)

Brian W. Bahder and Ericka E. Helmick

A UF/IFAS numbered Fact Sheet. in support of UF/IFAS Extension program: Integrated Pest Management

Management of Cucurbit Downy Mildew in Florida

Mason J. Newark, Mathews L. Paret, Nicholas S. Dufault, Pamela D. Roberts, Shouan Zhang, Gary E. Vallad, Josh Freeman, and Gene McAvoy

A UF/IFAS numbered Management. in support of UF/IFAS Extension program: Integrated Pest Management

Mancha foliar causada por Xanthomonas en Ficus elastica

E. V. Campoverde, A. J. Palmateer, and P. Lopez

Ornamental Ficus Diseases: Identification and Control in Commercial Greenhouse Operations

D. J. Norman and Gul Shad Ali

thumbnail for publication: Pepper Stip: An Abiotic Disorder of Unknown Cause Affecting Pepper Fruit

Pepper Stip: An Abiotic Disorder of Unknown Cause Affecting Pepper Fruit

Camille Esmel McAvoy and Pamela Roberts

Pepper stip (meaning speck in German), also referred to as color speck or colour spotting outside the US, is considered a physiological disorder of pepper. The disorder is believed to be related to high calcium status with levels of NH3-N and K playing a role. This 3-page factsheet of the UF/IFAS Plant Pathology Department summarizes known symptoms, causes, and potential environmental stressors that may result in stip development on peppers. Written by Camille McAvoy and Pamela Roberts.

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Showing 40 of 50 Experts

Kucharek, Thomas A

Kucharek, Thomas A

University of Florida

polymyxa@ufl.edu
Vallad, Gary E.

Vallad, Gary E.

University of Florida

gvallad@ufl.edu
Raid, Richard Neil

Raid, Richard Neil

University of Florida

rnraid@ufl.edu
Roberts, Pamela D.

Roberts, Pamela D.

University of Florida

pdr@ufl.edu
Brlansky, Ronald H.

Brlansky, Ronald H.

University of Florida

rhby@ufl.edu
Momol, Timur M.

Momol, Timur M.

University of Florida

tmomol@ufl.edu
Jones, Jeffrey B.

Jones, Jeffrey B.

University of Florida

jbjones@ufl.edu
Elliott, Monica Lynn

Elliott, Monica Lynn

University of Florida

melliott@ufl.edu
Harmon, Carrie Lapaire

Harmon, Carrie Lapaire

University of Florida

clharmon@ufl.edu
Marois, James J.

Marois, James J.

University of Florida

jmarois@ufl.edu
Stall, Robert E

Stall, Robert E

University of Florida

rest@ufl.edu
Batuman, Ozgur

Batuman, Ozgur

University of Florida

obatuman@ufl.edu
Folimonova, Svetlana

Folimonova, Svetlana

University of Florida

svetlana@ufl.edu
Derrick, Kenneth S

Derrick, Kenneth S

University of Florida

ksd1@ufl.edu
Harmon, Philip F.

Harmon, Philip F.

University of Florida

pfharmon@ufl.edu
Peres, Natalia A.

Peres, Natalia A.

University of Florida

nperes@ufl.edu
Timmer, Lavern W 'Pete'

Timmer, Lavern W 'Pete'

University of Florida

lwtimmer@ufl.edu
Bartz, Jerry A.

Bartz, Jerry A.

University of Florida

softbart@ufl.edu
Dawson, William O

Dawson, William O

University of Florida

wodtmv@ufl.edu
Zhang, Shouan

Zhang, Shouan

University of Florida

szhang0007@ufl.edu
Polston, Jane Elizabeth

Polston, Jane Elizabeth

University of Florida

jep@ufl.edu
Paret, Mathews L.

Paret, Mathews L.

University of Florida

paret@ufl.edu
Smith, Matthew E.

Smith, Matthew E.

University of Florida

trufflesmith@ufl.edu
Small, Ian M.

Small, Ian M.

University of Florida

ismall@ufl.edu
Levy, Amit

Levy, Amit

University of Florida

amitlevy@ufl.edu
Dufault, Nicholas S.

Dufault, Nicholas S.

University of Florida

nsdufault@ufl.edu
Norman, David J.

Norman, David J.

University of Florida

djn@ufl.edu
Dewdney, Megan M.

Dewdney, Megan M.

University of Florida

mmdewdney@ufl.edu
Harrison, Nigel A

Harrison, Nigel A

University of Florida

naha@ufl.edu
Pernezny, Ken

Pernezny, Ken

University of Florida

kenp@ufl.edu
Johnson, Evan G.

Johnson, Evan G.

University of Florida

egjohnson@ufl.edu
McGovern, Robert James

McGovern, Robert James

University of Florida

rjmcgov@ufl.edu
Gazis, Romina

Gazis, Romina

University of Florida

r.gazisseregina@ufl.edu
Ferreira, Larissa C.

Ferreira, Larissa C.

University of Florida

larissacarvalhof@ufl.edu
Viana Xavier, Katia

Viana Xavier, Katia

University of Florida

kvianaxavier@ufl.edu
Lemmond, Ben

Lemmond, Ben

University of Florida

blemmond@ufl.edu
Fullem, Kiersten

Fullem, Kiersten

University of Florida

kbushong@ufl.edu
Cullen, Matthew

Cullen, Matthew

University of Florida

mcullen1@ufl.edu
Silva de Moura, Vitor

Silva de Moura, Vitor

University of Florida

v.silvademoura@ufl.edu
Dhillon, Braham

Dhillon, Braham

University of Florida

dhillonb@ufl.edu