Bacterial Wilt — Infected plants with rotted roots. 
CARNATION MANUAL 
Bacterial wilt is the disease that is causing most concern among carnation growers. It is a 
relatively new disease for carnations, first being found by Dr. L. K. Jones in Washington State in 
1940. 
Sudden wilting of the tops or some of the branches in a characteristic symptom of bacterial wilt. 
Either one or more branches on one side of the plant wilts or the whole plant wilts. Distortion due 
to the tendency of the plant to curl to one side as in Fusarium wilt is not evident when the plant 
is affected by bacterial wilt. Internally the stems are yellowish to brown and if wilting is confined 
to one side of the plant the discoloration is usually restricted to that side. The bark on the lower 
part of the stems disintegrates and becomes soft, and the discolored wood underneath is sticky to 
the touch. The root systems are rotted, most of them remaining in the soil when the plant is lifted. 
These roots also have a sticky character. This sticky character of disintegrating root and stem tissues 
distinguishes bacterial wilt from other wilt and root rot diseases. 
The bacterium responsible for the disease enters through the root and basal part of stem. This is a 
high temperature organism and it works most effectively during the summer when temperatures are 
in the 90's. It works slowly in the wintertime and infected plants may not show symptoms until 
summertime. This is important, as cuttings are frequently taken from apparently healthy plants in 
the winter and the disease does not become evident until hot weather. 
Soil sterilization with steam only; otherwise the same general precautions as for Fusarium wilt. 
If hormones are used on the cuttings, apply them with a powder blower, never in a solution into 
which cuttings are dipped. 
Vd F 
i 
Bacterial Wilt — Showing appearance of dying plant; entire 
plant is affected. 
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