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    Plant Pathology

    Plant Pathology

    Spore Report

    2025 Potato Spore Reports

    • March 17, 2025
    • March 24, 2025
    • March 31, 2025
    • April 7, 2025
    • April 14, 2025
    • April 21, 2025

    For specific spore reports, click on the dated links to the left

    Potato Late Blight Disease Resources  

    Late blight: UF IFAS 

    Potato late blight: North Carolina State University  

    Potato late blight: North Dakota State University  

    Potato late blight: University of California  

     

    Early Blight of Potato Resources  

    Early Blight of Potato: The American Phytopathological Society (APS) 

    Early blight: University of California  

    Early blight and potato late blight: University of Connecticut  

    Early blight in potato: University of Minnesota  

     

    Brown Leafspot of Potato Resources  

    Brown leafspot: Michigan State University 

    March 17, 2025

     

    march 17 spore report

    Early blight/brown spots fungal spores associated with Alternaria solani and Alternaria alternata (A) were detected in both passive and active spore traps strategically placed in potato commercial fields at St. Johns and Putnam Counties, indicating potential disease risks under favorable conditions. However, late blight spores, usually associated with Phytophthora sp. (P), were not detected across all traps, suggesting no immediate risk for late blight at the time of sampling.  

    The detection of fungal spores highlights the importance of proactive field monitoring and data-driven decision-making for effective disease management. Growers are encouraged to stay vigilant and refine their management strategies, using spore reports as a guide tool, alongside prevailing environmental conditions, to mitigate potential risks. 

     

    Environmental Conditions Favoring Disease Development 

    Early Blight (Alternaria solani) 
    Spore germination and infection primarily occur under favorable temperatures range of 68–86°F (20 to 26°C), high humidity, and extended leaf wetness. Frequent dew formation, overhead irrigation, fog, poor airflow, and rainfall increase disease risk.  

    Brown Spot (Alternaria alternata) 
    Long dew periods, humid environments, and temperatures between 64- 86°F (18 to 30°C) are favorable for spore germination and penetration. Disease severity increases with frequent wet-dry cycles, especially when rainfall or irrigation prolongs leaf surface moisture.  

    Late Blight (Phytophthora infestans) 
    The pathogen favors cool to moderate temperatures ranging from 50–75°F (10 to25°C) with high relative humidity (≥90%) or leaf wetness periods exceeding 10 hours. Risk increases during cool nights with dew, fog, or persistent moisture. Sporangia, as inoculum, are easily dispersed by wind and wind-driven rain, facilitating the disease to spread rapidly. 

    Spore Report Alert System  

    🔴 Red: Spores detected, indicating a potential disease risk.  

    🟡 Yellow: Spores detected in 1-2 spore traps, indicating close monitoring.   

    🟢 Green: No spores detected, indicating no immediate concern.  

     

     

     

     

    march 24 spore report

    Alternaria early blight and brown spot fungal spores, associated with Alternaria solani and Alternaria alternata (A), respectively, were detected in all four passive and active spore traps placed strategically in commercial potato fields and experimental station in St. Johns County. Meanwhile, spores of these diseases were detected in three spore trap samplers at Putnam County. This widespread detection suggests a potential risk of disease development under favorable environmental conditions.   

    Additionally, Phytophthora sp. (P), usually associated with potato late blight in potato fields, was detected at Location No. 2 in St. Johns County from two spore traps and Location No. 3 in Putnam County from one active spore trap. The detection highlights close monitoring/ moderate risk of late blight, particularly if weather conditions continue to favor pathogen activity.  

    The detection of fungal spores highlights the importance of proactive field monitoring and data-driven decision-making for effective disease management. Growers are encouraged to stay vigilant and refine their management strategies, using spore reports as a guide tool alongside prevailing environmental conditions to mitigate potential risks.  

    Environmental Conditions Favoring Disease Development 

    Early Blight (Alternaria solani) 
    Spore germination and infection primarily occur under favorable temperatures range of 68–86°F (20 to 26°C), high humidity, and extended leaf wetness. Frequent dew formation, overhead irrigation, fog, poor airflow, and rainfall increase disease risk.  

    Brown Spot (Alternaria alternata) 
    Long dew periods, humid environments, and temperatures between 64- 86°F (18 to 30°C) are favorable for spore germination and penetration. Disease severity increases with frequent wet-dry cycles, especially when rainfall or irrigation prolongs leaf surface moisture.  

    Late Blight (Phytophthora infestans) 
    The pathogen favors cool to moderate temperatures ranging from 50–75°F (10 to25°C) with high relative humidity (≥90%) or leaf wetness periods exceeding 10 hours. Risk increases during cool nights with dew, fog, or persistent moisture. Sporangia, as inoculum, are easily dispersed by wind and wind-driven rain, facilitating the disease to spread rapidly. 

    Spore Report Alert System  

    🔴 Red: Spores detected, indicating a potential disease risk.  

    🟡 Yellow: Spores detected in 1-2 spore traps, indicating close monitoring.   

    🟢 Green: No spores detected, indicating no immediate concern.  

     

    March 31 spore report

    Pathogen

    Disease

    Detection Summary*

    Alternaria solani

    Alternaria Alternata

    Early blight

    Brown Spot

    Detected in all traps – St. Johns Co.

    Detected in 3 traps – Putnam Co.

    Phytophthora infestans

    Late Blight

    Detected in 2 traps – St. Johns Co.

    Detected in 1 trap – Putnam Co.

     *Spore presence = potential, not guarantee. Combine spore data with crop stage, cultivar susceptibility, and local weather to guide your actions.

    Alternaria early blight and brown spot fungal spores, associated with Alternaria solani and Alternaria alternata (A), respectively, were detected in all four passive and active spore traps placed strategically in commercial potato fields and experimental station in St. Johns County. Meanwhile, spores of these diseases were detected in three spore trap samplers at Putnam County. This widespread detection suggests a potential risk of disease development under favorable environmental conditions.  

    Additionally, Phytophthora sp. (P), usually associated with potato late blight in potato fields, was detected at Location No. 2 in St. Johns County from two spore traps and Location No. 3 in Putnam County from one active spore trap. The detection highlights close monitoring/ moderate risk of late blight, particularly if weather conditions continue to favor pathogen activity.

    The detection of fungal spores highlights the importance of proactive field monitoring and data-driven decision-making for effective disease management. Growers are encouraged to stay vigilant and refine their management strategies, using spore reports as a guide tool alongside prevailing environmental conditions to mitigate potential risks. 

    Environmental Conditions Favoring Disease Development

    Early Blight (Alternaria solani)
    Spore germination and infection primarily occur under favorable temperatures range of 68–86°F (20 to 26°C), high humidity, and extended leaf wetness. Frequent dew formation, overhead irrigation, fog, poor airflow, and rainfall increase disease risk.

    Brown Spot (Alternaria alternata)
    Long dew periods, humid environments, and temperatures between 64- 86°F (18 to 30°C) are favorable for spore germination and penetration. Disease severity increases with frequent wet-dry cycles, especially when rainfall or irrigation prolongs leaf surface moisture.

    Late Blight (Phytophthora infestans)
    The pathogen favors cool to moderate temperatures ranging from 50–75°F (10 to25°C) with high relative humidity (≥90%) or leaf wetness periods exceeding 10 hours. Risk increases during cool nights with dew, fog, or persistent moisture. Sporangia, as inoculum, are easily dispersed by wind and wind-driven rain, facilitating the disease to spread rapidly.

     

    Spore Report Alert System 

    🔴 Red: Spores detected, indicating a potential disease risk. 

    🟡 Yellow: Spores detected in 1-2 spore traps, indicating close monitoring.  

    🟢 Green: No spores detected, indicating no immediate concern.

     

     

     

     

    april 7 spore report 

    Pathogen 

    Disease 

    Detection Summary* 

    Alternaria solani  

    Alternaria alternata 

    Early blight 

    Brown Spot 

    Detected in all traps – St. Johns Co. 

    Detected in 3 traps – Putnam Co. 

    Phytophthora infestans 

    Late Blight 

    Not detected  

     *Spore presence = potential, not guarantee. Combine spore data with crop stage, cultivar susceptibility, and local weather to guide your actions. 

    Alternaria early blight and brown spot fungal spores, associated with Alternaria solani and Alternaria alternata (A), respectively, were detected in all four passive and active spore traps placed strategically in commercial potato fields and experimental station in St. Johns County. Meanwhile, spores of these diseases were detected in three spore trap samplers at Putnam County. This widespread detection suggests a potential risk of disease development under favorable environmental conditions.   

    Additionally, Phytophthora sp. (P), usually associated with late blight in potato fields, was not detected in both Counties, specifying no immediate risk at the time of sampling.  

    The detection of fungal spores highlights the importance of proactive field monitoring and data-driven decision-making for effective disease management. Growers are encouraged to stay vigilant and refine their management strategies, using spore reports as a guide tool alongside prevailing environmental conditions to mitigate potential risks.  

    Environmental Conditions Favoring Disease Development 

    Early Blight (Alternaria solani) 
    Spore germination and infection primarily occur under favorable temperatures range of 68–86°F (20 to 26°C), high humidity, and extended leaf wetness. Frequent dew formation, overhead irrigation, fog, poor airflow, and rainfall increase disease risk.  

    Brown Spot (Alternaria alternata) 
    Long dew periods, humid environments, and temperatures between 64- 86°F (18 to 30°C) are favorable for spore germination and penetration. Disease severity increases with frequent wet-dry cycles, especially when rainfall or irrigation prolongs leaf surface moisture.  

    Late Blight (Phytophthora infestans) 
    The pathogen favors cool to moderate temperatures ranging from 50–75°F (10 to25°C) with high relative humidity (≥90%) or leaf wetness periods exceeding 10 hours. Risk increases during cool nights with dew, fog, or persistent moisture. Sporangia, as inoculum, are easily dispersed by wind and wind-driven rain, facilitating the disease to spread rapidly. 

     

    Spore Report Alert System  

    🔴 Red: Spores detected, indicating a potential disease risk.  

    🟡 Yellow: Spores detected in 1-2 spore traps, indicating close monitoring.   

    🟢 Green: No spores detected, indicating no immediate concern.  

     

     

     

    April 14 spore report

    Pathogen 

    Disease 

    Detection Summary* 

    Alternaria solani  

    Alternaria alternata 

    Early blight 

    Brown Spot 

    Detected in all traps – St. Johns Co.  

    Detected in all traps – Putnam Co. 

    Phytophthora sp.  

    Late Blight 

    Detected in one trap- St. Johns and Putnam Co.  

     

    Alternaria early blight and brown spot fungal spores, associated with Alternaria solani and Alternaria alternata (A), respectively, were detected in all four passive and active spore traps placed strategically in commercial potato fields and experimental station in St. Johns County. Meanwhile, spores of these diseases were also detected in all spore traps at Putnam County. This widespread detection suggests a potential risk of disease development under favorable environmental conditions.   

    Additionally, Phytophthora sp. (P), usually associated with potato late blight in potato fields, was detected in all sampling locations from one active spore trap. The detection highlights close monitoring/ moderate risk of late blight, particularly if weather conditions continue to favor pathogen activity. 

    The detection of fungal spores highlights the importance of proactive field monitoring and data-driven decision-making for effective disease management. Growers are encouraged to stay vigilant and refine their management strategies, using spore reports as a guide tool alongside prevailing environmental conditions to mitigate potential risks.  

    Environmental Conditions Favoring Disease Development 

    Early Blight (Alternaria solani) 
    Spore germination and infection primarily occur under favorable temperatures range of 68–86°F (20 to 26°C), high humidity, and extended leaf wetness. Frequent dew formation, overhead irrigation, fog, poor airflow, and rainfall increase disease risk.  

    Brown Spot (Alternaria alternata) 
    Long dew periods, humid environments, and temperatures between 64- 86°F (18 to 30°C) are favorable for spore germination and penetration. Disease severity increases with frequent wet-dry cycles, especially when rainfall or irrigation prolongs leaf surface moisture.  

    Late Blight (Phytophthora infestans) 
    The pathogen favors cool to moderate temperatures ranging from 50–75°F (10 to25°C) with high relative humidity (≥90%) or leaf wetness periods exceeding 10 hours. Risk increases during cool nights with dew, fog, or persistent moisture. Sporangia, as inoculum, are easily dispersed by wind and wind-driven rain, facilitating the disease to spread rapidly. 

     

    Spore Report Alert System  

    🔴 Red: Spores detected, indicating a potential disease risk.  

    🟡 Yellow: Spores detected in 1-2 spore traps, indicating close monitoring.   

    🟢 Green: No spores detected, indicating no immediate concern.  

    April 21 spore report

    Pathogen 

    Disease 

    Detection Summary* 

    Alternaria solani  

    Alternaria alternata 

    Early blight 

    Brown Spot 

    Detected in 3 traps – St. Johns Co.  

    Detected in all traps – Putnam Co. 

    Phytophthora sp.  

    Late Blight 

    Detected in one trap- St. Johns and Putnam Co.  

     

    Alternaria early blight and brown spot fungal spores, associated with Alternaria solani and Alternaria alternata (A), respectively, were detected in three spore traps spore traps placed strategically in commercial potato fields and experimental station in St. Johns County. Meanwhile, spores of these diseases were also detected in all spore traps at Putnam County. This widespread detection suggests a potential risk of disease development under favorable environmental conditions.   

    Additionally, Phytophthora sp. (P), usually associated with potato late blight in potato fields, was detected in St. Johns and Putnam Counties from one active spore trap. The detection highlights close monitoring/ moderate risk of late blight, particularly if weather conditions favor pathogen activity. 

    The detection of fungal spores highlights the importance of proactive field monitoring and data-driven decision-making for effective disease management. Growers are encouraged to stay vigilant and refine their management strategies, using spore reports as a guide tool alongside prevailing environmental conditions to mitigate potential risks.  

    Environmental Conditions Favoring Disease Development 

    Early Blight (Alternaria solani) 
    Spore germination and infection primarily occur under favorable temperatures range of 68–86°F (20 to 26°C), high humidity, and extended leaf wetness. Frequent dew formation, overhead irrigation, fog, poor airflow, and rainfall increase disease risk.  

    Brown Spot (Alternaria alternata) 
    Long dew periods, humid environments, and temperatures between 64- 86°F (18 to 30°C) are favorable for spore germination and penetration. Disease severity increases with frequent wet-dry cycles, especially when rainfall or irrigation prolongs leaf surface moisture.  

    Late Blight (Phytophthora infestans) 
    The pathogen favors cool to moderate temperatures ranging from 50–75°F (10 to25°C) with high relative humidity (≥90%) or leaf wetness periods exceeding 10 hours. Risk increases during cool nights with dew, fog, or persistent moisture. Sporangia, as inoculum, are easily dispersed by wind and wind-driven rain, facilitating the disease to spread rapidly. 

     

    Spore Report Alert System  

    🔴 Red: Spores detected, indicating a potential disease risk.  

    🟡 Yellow: Spores detected in 1-2 spore traps, indicating close monitoring.   

    🟢 Green: No spores detected, indicating no immediate concern.  

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