Pythium species cause damping-off, root rot, crown and stem rot of all plant species. The roots of these snapdragon transplants are infected with Pythium root rot resulting in stunted and wilted plants. Pythium is favored by high fertility and high moisture; avoid overwatering and overfertilizing. Pythium is a natural inhabitant of the soil and can survive there indefinitely as well as in dirt and debris in the greenhouse. To prevent Pythium, use soilless growing media, keep hose ends off the floor and avoid contaminating growth medium with via hands, tools, or flats. Biological and chemical methods are available for controlling these insects. Fungicides labeled for Pythium include: Group 33 fosetyl-Al (Aliette), phosphorous acid 33 (Alude), phoshites (FOSPHITE) Group 28 propamocarb (Banol) Group 14 +1) etridiazole plus thiophanate methyl (Banrot) Group 4 mefonoxam (Subdue MAXX) Group 14 etridiazole (Truban).
Many greenhouse isolates of Pythium are resistant to Subdue. Rotate fungicide applications among active ingredient groups (FRAC code) to avoid resistance development in the pathogen population.