Cause Pythium spp., Rhizoctonia solani, and Fusarium spp. Pythium is favored by cool, overly wet soil conditions, Rhizoctonia by warm soil temperatures.
Symptoms Seedlings either fail to emerge from soil or collapse soon after emergence, after a girdling canker develops at the soil line.
Cultural control
- Plant seed under optimal conditions for quick emergence and vigorous growth.
- Use sterile soil or potting mix to start seeds. Also disinfect any tools and equipment that might be used and contaminate the media.
- Avoid reusing pots or trays from a previous crop for propagation. If pots must be reused then wash off all debris and soak in a sanitizing solution or treat with aerated steam for 30 min.
Chemical control
- Seed treatment.
- Allegiance-FL (Group 4) at 0.75 fl oz/100 lb seed plus a dye can be used where Pythium spp. are a problem. See label for reentry restrictions.
- Apron XL (Group 4) at 0.085 to 0.64 fl oz/100 lb seed plus a dye, can be used where Pythium spp. are a problem. See label for reentry restrictions.
- Dynasty (Group 11) at 0.10 to 0.38 fl oz/100 lb seed plus a dye. Use in combination with other active ingredients labeled for seed treatment. See label for reentry restrictions.
- Fludioxonil formulations (Group 12) such as Fludioxonil 4L ST and Dyna-Shield Fludioxonil or Maxim 4FS at 0.08 to 0.16 fl oz/100 lb seed for control of pathogenic Fusarium and Rhizoctonia spp. See label for reentry restrictions.
- Oxidate 2.0 is registered for seed treatment for seed crops and will aid in removing seedborne pathogens. Use a dilution of 1:100 or 64 fl oz/50 gal of water. Immerse seed for 2 minutes. Do not rinse. See label for reentry interval.
- 42-S Thiram at 8 fl oz/100 lb seed plus a dye. See label for reentry restrictions.
- Soil treatment.
- Quadris Flowable at 0.4 to 0.8 fl oz/1000 row feet applied in a 7-inch or less band either in-furrow at planting or as a directed spray at cultivation. 4-hr reentry.
- Uniform at 0.34 fl oz/1000 row feet applied in a 7-inch band in-furrow at planting. 0-hr reentry.
Biological control Efficacy in the Pacific Northwest is unknown.
- Actinovate AG at 3 to 12 oz/A as a soil drench at planting. 4-hr reentry. O
- Actinovate Lawn & Garden at 1/2 to 1 teaspoon/gal water. H O
- Bexfond at 7 to 14 fl oz/A. O
- Bio-Tam 2.0 at 2.5 to 5 lb/A as a broadcast at sowing. See label for different methods and rates of application. 4-hr reentry. O
- Cease at 3 to 6 quarts in 100 gal water applied to soil at 1 pint/sq ft for each 3-inches of soil depth on 21- to 28-day intervals. For greenhouse plants only. 4-hr reentry. O
- Double Nickel LC at 0.5 to 4.5 pints/A for soil application on 14- to 28-day intervals. Can be applied the day of harvest. 4-hr reentry. O
- Prestop WG as a soil drench or incorporation into growing medium. 4-hr reentry. O
- Rootshield WP at 3 to 5 oz/100 gal water for greenhouse soil drench and field chemigation or at 16 to 32 oz/A as an in-furrow spray. 4-hr reentry. O
- SoilGard at 0.5 to 10 lb/A at 4-week intervals will suppress Pythium and Rhizoctonia. See label for specific application types and timings. Can be applied on the day of harvest. 4-hr reentry. O
- Tenet WP at 2.5 to 5.0 lb/A at sowing will suppress certain fungal pathogens including Fusarium, Rhizoctonia, and Pythium spp. See label for specific application types and timings. 1-hr reentry. O