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Pythium Root
Rot (Pythium spp.) - Similar to
Rhizoctonia in that it causes both damping-off as well as foot rot
in plant cuttings. However, infection occurs in cool, wet,
poorly-drained soils, and by over-watering. Infection results in
a wet odorless rot. Species of Pythium can survive for
several years in soil and plant debris.
Phytophthora
Root Rot (Phytophthora spp.) - Usually associated with root
rots of established plants but are also involved in damping-off in
seedlings. These species enter the root tips and cause a
water-soaked brown to black rot similar to
Pythium. Survives indefinitely in soil and plant debris.
Rhizoctonia
Root Rot (Rhizoctonia solani) - A fungi which causes
damping-off of seedlings and foot rot of plant cuttings.
Infection occurs in soils with warm to hot temperatures and moderate
moisture levels. The fungi is found in all natural soils and can
survive indefinitely. Infected plants often have slightly sunken
lesions on the stem at or below the soil line. Transferring this
fungi from nature to your germination area or greenhouse is as simple
as using the same tools out of doors as you do in. Do not use
your germination area to mix potting soils or transplanting seedlings
using soils. Cleanliness is key here.
There are also other miscellaneous fungi
which cause similar symptoms. These include Sclerotinia
(white mold), Sclerotium rolfsii, Macrophomina phaseoli,
some species of Botrytis (gray mold), Aphonomyces,
Fusarium, and Cylindrocladium.
Preventative measures include:
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Utilizing sterile, soiless mixes for
seed starting and rooting of cuttings.
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Sterilize tools, trays and pots with a
10:1 ration of water and household chlorine bleach.
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Provide adequate airflow and
ventilation in the germination area using fans if necessary.
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Provide optimum soil temperatures for
the plant variety that you are germinating.
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Avoid over watering and bottom
watering. Saturate the soil but allow good drainage and apply
no more water until just before the plants approach wilt stage.
Additional Information:
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