Cause Pythium spp., Rhizoctonia solani, and Fusarium spp., possibly other pathogens can cause a seed rot and seedling blight known as damping-off. These soilborne fungi or fungus-like microorganisms can persist indefinitely in soil or plant debris. Rhizoctonia can be transmitted on seed. Damping-off is favored by wet soils.
Symptoms Seeds may rot prior to germination ("seed decay"), or the seedling may become infected prior to emergence ("pre-emergence damping-off") or soon after emergence ("post-emergence damping-off"). In the latter cases, the stem of the seedling becomes infected and tissues become discolored and soft, resulting in the seedling toppling over after it has emerged from the ground. Stem infections occurring late in the seedling stage may cause a canker or "wire stem" symptom in which the plant doesn't die, but it is stunted, unthrifty, and may produce adventitious roots. Infections may be mild if only feeder roots are attacked.
Cultural control
- Plant seed in warm (over 55°F), moist soil after frost danger has passed.
- Tillage practices that decrease plant residues on the soil surface may result in less disease.
- Crop rotation can help reduce pathogen populations, avoid planting after other legume crops.
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 0.16 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.
- Captan 4F (Group M4) at 2.6 fl oz/100 lb seed plus a dye. Controls a broad spectrum of fungi.
- Dynasty (Group 11) at 0.153 to 0.765 fl oz/100 lb seed plus a dye. Use in combination with other active ingredients labeled for seed treatment. See label for reentry restrictions.
- Maxim 4FS (Group 12) at 0.08 to 0.16 fl oz/100 lb seed for control of pathogenic Fusarium and Rhizoctonia spp. See label for reentry restrictions.
- Obvius (Group 4 + 7 + 11) at 4.6 fl oz/100 lb seed plus a dye. A broad-spectrum seed fungicide combination for dry bean and field beans. 24-hr reentry.
- Stamina (Group 11) at 0.4 to 1.5 fl oz/100 lb seed plus a dye. Use in combination with other active ingredients labeled for seed treatment.
- 42-S Thiram at 2 fl oz/100 lb seed plus a dye. See label for reentry restrictions.
- Vibrance (Group 7) at 0.08 to 0.16 fl oz/100 lb seed plus a dye for dry bean only. See label for reentry restrictions.
- Vitavax-34 (Group 7) at 3 to 4 fl oz/100 lb seed plus a dye. See label for reentry restrictions.
- Soil treatment.
- C-O-C-S WDG at 4 lb/100 gal water or at 2 oz/3 gal water. Can be re-applied on a minimum of 3-day intervals. Do not apply through any irrigation system. 48-hr reentry; 24-hr reentry for greenhouse applications.
- 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.
- Ridomil Gold SL may be banded or surface applied at 0.5 to 1 pint/A. Band-rate determinants include band width and row spacing; see label. Incorporate 2-inches deep when used. 48-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
- 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
- Amplitude ST at 2 to 8 fl oz/100 lb seeds. Preharvest interval is 0 days. 4-hr reentry. 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
- Double Nickel LC at 0.5 to 4.5 pints/A as a soil drench at planting. 4-hr reentry. O
- Heads Up at 0.035 oz/34 fl oz water/360 lb seed will stimulates pest suppression system of plants. Efficacy unknown. 12-hr reentry. O
- Mycostop at 0.07 oz/lb seed. 4-hr reentry. O
- Prestop WG as a soil drench or incorporation into growing medium. 4-hr reentry. O
- SoilGard at 2 to 10 lb/A on 1- to 4-week intervals will suppress Pythium and Rhizoctonia. See label for greenhouse and transplant application rates and timing. Do not apply to very dry, compacted, frozen, or water-logged soils. After application, do not over-water or allow soil to become saturated for longer than 3 hours. 4-hr reentry. O
- Stargus at 6 to 8 fl oz per 1,000 ft row as an in-furrow treatment. Preharvest interval is 0 days. 4-hr reentry. O
- Tenet WP 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