Cause The soilborne fungi or fungus-like microorganisms, Fusarium spp., Pythium spp., and Rhizoctonia solani, may attack before, during, and after germination. In the Pacific Northwest, Pythium spp. are the major cause of pre- and post-emergence damping-off of young dill seedlings. Pythium is favored by cool, wet soils. Rhizoctonia solani is more often associated with post-emergence damping-off of older seedlings and soil temperatures are warm; it is favored by warmer soil temperatures. These fungi can survive several years in soil and can infect other plant species including beans and other vegetable crops.
Symptoms Seeds either do not emerge, or emerged seedlings often develop blackened stems and wilt. Very few infected seedlings survive and root die-back maybe evident.
Cultural control
- Encourage rapid emergence by managing planting depth (shallow), timing, and soil moisture. Work soil at moisture conditions that reduce soil compaction.
- Avoid planting in wet or poorly-drained soil.
- Rotate dill crops with grass and grain.
- Use good quality seed.
- If the stand is lost, replant ideally in dry, warm weather, which is more favorable for germination.
Chemical control Efficacy in the Pacific Northwest is unknown.
- Treat seed with fungicide.
- Acquire at 0.75 fl oz/100 lb seed plus a dye. For control of Pythium only. See label for reentry restrictions.
- Maxim 4FS at 0.08 to 0.16 fl oz/100 lb seed plus a dye. For control of pathogenic Fusarium and Rhizoctonia spp. 12-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. H O
- Bexfond at 7 to 14 fl oz/A. O
- Double Nickel LC at 0.5 to 4.5 pints/A as a soil drench at planting. 4-hr reentry. O
- Mycostop at 0.07 oz/lb seed. 4-hr reentry. O
- Prestop WG at 1.4 to 14 oz/10 gal water (0.1% to 1.0% suspension) 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