Cause Pythium ultimum or Rhizoctonia solani, fungus-like and fungal microorganisms that live in soil and attack seedlings of many different crops. As seedlings mature, they become resistant to attack. The disease can be a serious problem in cool, wet soils.
Symptoms Seedlings may be attacked before or after they emerge from the soil, resulting in gaps and uneven stands. Young plants suddenly wilt and topple over. Water-soaked lesions are apparent on stems at the soil line.
Cultural control
- Delay planting until soil warms to increase seedling growth and emergence.
- Mulch soil to increase soil temperature.
- Plant shallowly to promote quick emergence and growth.
Chemical control
- Treat seed with fungicide.
- Allegiance-FL (Group 4) at 0.75 fl oz/100 lb seed plus a dye. To control Pythium spp. only. See label for reentry restrictions.
- Apron XL (Group 4) at 0.085 to 0.64 fl oz/100 lb seed plus a dye. Controls Pythium only. See label for reentry restrictions.
- Dynasty (Group 11) at 0.1 to 0.38 fl oz/100 lb seed plus a dye. 4-hr reentry.
- Maxim 4FS (Group 12) at 0.08 to 0.16 fl oz/100 lb seed plus a dye. For control of pathogenic Fusarium and Rhizoctonia spp. See label for reentry restrictions.
- 42-S Thiram (Group M3) at 8 fl oz/100 lb seed plus a dye for commercial application only (no home use). To control pathogenic Fusarium, Rhizoctonia, and other fungal spp. See label for reentry restrictions.
- C-O-C-S WDG (Group M1) at 1 to 1.9 lb/A on 5-day intervals. Do not apply through any irrigation system. 48-hr reentry; 24-hr reentry for greenhouse applications.
- Orondis Gold (Group 49 + 4) at 13.9 to 27.8 fl oz/A as an in-furrow, transplant water or banded soil application at planting. May be applied through drip after emergence. Preharvest interval is 7 days. 48-hr reentry.
- Quadris Flowable (Group 11) at 0.4 to 0.8 oz/1,000 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.
Biological control Efficacy in the Pacific Northwest is unknown.
- Bexfond at 7 to 14 fl oz/A. 4-hr reentry. O
- Cease at 3 to 6 quarts in 100 gal water applied to soil at 1 pint/square ft for each 3-inches of soil depth on a 21- to 28-day interval. For greenhouse plants only. 4-hr reentry. O
- Double Nickel LC at 1 to 2 quarts/A as a banded soil spray or drench on 4- to 6-week intervals or at 0.5 to 4.5 pints/A on 2- to 4-week intervals. Can be applied the day of harvest. 4-hr reentry. O
- Rootshield WP at 3 to 8 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 2 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