Michigan State University Extension
Ornamental Plants plus Version 3.0 - 00000526
11/12/99
DIEFFENBACHIA DISEASE PROBLEMS
Bacterial leaf spot causes very small, yellow or
yellowish-orange spots with translucent centers. The
spots enlarge up to 1/2 inch and run together. Under
drier conditions the spots do not enlarge but turn reddish
brown giving a speckled appearance. Numerous spots cause
infected leaf parts to yellow, wilt and die. Under moist
air conditions large mounds of bacterial ooze appear on
the lower surface of the spots. Dried ooze is a waxy,
silvery-white layer covering the spots. The ooze may later
appear on the upper surface of the spots. Prevention
includes avoidance of lower temperatures, crowding and
syringing.
A fungal leaf spot causes very small reddish brown lesions
on the young leaves. On unrolled leaves, the spots may be
1/4 inch or more in diameter with a dark brown border.
When the lesions run together yellowing and death of the
entire leaf occur. The infection can occur through wounds
caused by mealybugs. Keep the temperature and humidity
down and control mealybugs.
Stem and leaf rot causes brownish, water-soaked, sunken
areas in the stem. The leaves have irregular brownish
soft spots.
At least two root and stem rots will cause rotting of
roots and lower stems.
Related information.
Pesticide Recommendations
This information is for educational purposes only. References
to commercial products or trade names does not imply
endorsement by MSU Extension or bias against those not
mentioned. This information becomes public property upon
publication and may be printed verbatim with credit to MSU
Extension. Reprinting cannot be used to endorse or advertise
a commercial product or company.
This file was generated from data base ZZ on 01/19/00.
Data base ZZ was last revised on 11/12/99.
For more information about this data base or its contents please contact
heatley@msue.msu.edu . Please read our
disclaimer for important
information about using our site.