Pythium spp. Associated with Bell Pepper Production in Florida

Area of Science:

• Plant Pathology
• Mycology
• Agricultural Science

Background:

• Pythium species are known soilborne pathogens affecting various crops.
• Polyethylene-mulched production systems can harbor plant pathogens.
• Understanding pathogen virulence is crucial for crop protection.

Purpose of the Study:

• To identify Pythium species associated with bell pepper root systems.
• To evaluate the pathogenicity of these Pythium species on pepper and tomato plants.
• To determine the influence of temperature on pathogen virulence.

Main Methods:

• Isolation and identification of Pythium species from pepper roots.
• Pathogenicity assays in controlled soil conditions using pepper and tomato.
• Assessment of root rot, plant weight, and mortality.
• Evaluation of temperature effects on disease severity.

Main Results:

• Ten Pythium species and one unidentified group were recovered from pepper roots.
• P. aphanidermatum and P. myriotylum caused severe root rot, reduced growth, and significant mortality in pepper.
• P. aphanidermatum and P. myriotylum also affected tomato growth but caused less mortality.
• Other tested Pythium species showed varying degrees of colonization or mild root tip necrosis without significant growth reduction.
• Optimal disease development for P. aphanidermatum and P. myriotylum occurred at 28°C, with mortality at 34°C.

Conclusions:

• Pythium aphanidermatum and P. myriotylum pose significant threats to pepper production.
• Pathogenicity varies among Pythium species and host plants (pepper vs. tomato).
• Temperature is a critical factor influencing the severity of Pythium-induced diseases in pepper transplants.