Diseases of pepper (
Seedling damping off
Pythium aphanidermatum
Rhizoctonia solani
The most common cause of damping-off of peppers in greenhouse nurseries in Arizona is Pythium aphanidermatum. This fungal-like organism causes root and stem rot, and young plants die quickly, especially at warm temperatures. The pathogen is disseminated in soil, infested plant debris and greenhouse materials, and in water. P. aphanidermatum can be especially devastating in hydroponic systems since the asexual reproductive spore, the zoospore, is produced in aqueous conditions and moves rapidly in water or water films. Untreated, recycled water is a common source of inoculum.
In the field, Rhizoctonia solani is usually more of a problem. Chile peppers are often directly seeded into the field, and if cool temperatures persist through the germination period, chile seedlings may die quickly from Rhizoctonia infection. Healthy transplants are generally not as susceptible.
In the greenhouse, sanitation is the most important component of prevention and control. Disease can be reduced by cultural practices including careful use of clean planting media and soil, thorough disinfestations after an infected crop, control of fungal gnats and shore flies, and careful disposal of infected plants away from the greenhouse. In the field, seed or transplants should be planted after soils warm.
More information is available in the publication “Damping-off” available at:
http://ag.arizona.edu/pubs/crops/az1029.pdf
February 24, 2003