Feb 22, 2018
Bayer Releases Guide to Controlling Seedling Diseases

Aaron Palmateer, technical specialist on the Bayer Green Solutions Team recently compiled this quick-hit guide to help growers control seedling diseases such as Pythium, Fusarium and Rhizoctonia.

Controlling Seedling Diseases 101

By Aaron Palmateer

Plant propagation can be challenging enough without the onset of disease, but warm and humid conditions necessary for seed germination or rooting cuttings also favor pathogens.

Germinating seeds and newly-emerging roots and hypocotyls are often attacked by soil-borne plant pathogens that can cause major losses due to post and preemergence damping off, or low quality plants and poor performance.

  • Pathogens – Fusarium spp., Pythium spp. and Rhizoctonia solani are the primary
    Damping off at germination (Bayer).

    culprits, but any pathogens present in the growing medium (i.e., PhytophthoraBotrytis and Thielaviopsis) are capable of attacking young plants.

  • Symptoms – Pre-emergence damping off occurs below the soil, where the pathogen attacks the emerging root or hypocotyl before full emergence, and results in poor stands.  Post-emergence damping off results in rotten discolored stems at or near the soil line and root decay.  Affected seedlings often appear shriveled brown, collapsed or stunted.
  • Host Range – Seedling disease pathogens are widely distributed and are capable of attacking all stages of propagation material in greenhouses and nursery crops, including annuals, perennials, foliage plants and woody ornamentals.

    Damping off after germination (Bayer).
  • Cultural Control – Seedling diseases are difficult to control curatively, so the best approach is prevention. Follow strict sanitation measures and choose resistant plant varieties when available.  Propagation areas should be weed free. Avoid overwatering and bedding mixes that retain water.
  • Chemical Control – Preventative fungicide applications are almost essential under the conditions for propagation. Chipco 26019 FLO and Compass can be used for control of both Rhizoctonia and Fusarium. Prostar is excellent for Rhizoctonia and Aliette WDG, Banol and Fenstop are effective for controlling Pythium (refer to product labels for directions).

For more information, please visit www.backedbybayer.com/production-ornamentals.

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