Root Rot of Potted Tulips
Tom Creswell, P&PDL Director, Plant Disease Diagnostician,
We see few problems on tulips grown in pots
for winter forcing, but growers occasionally encounter root rot
problems with this crop. Symptoms on the foliage may include
stunting, dead leaf tips, weak or distorted growth and yellowing.
Healthy tulips at the bloom stage should show creamy white roots
on the outside of the root ball but fungal pathogens can cause
discoloration and decay.
Once the roots are heavily infected there is little
that can be done to help plants recover. Prevention depends on
starting with strong, healthy bulbs that have been properly conditioned
for forcing and maintaining good sanitation throughout the growth
stages. Commercial growers may also need to use fungicide drenches
to help prevent the most common problems like Rhizoctonia root
rot and Pythium root rot.
Click image to enlarge
Figures 1 & 2: Potted tulips showing symptoms of root decay problems.
Figure 3: Leaf tip dieback resulting from root rot.
Figure 4: Root rot caused by Pythium and Rhizoctonia.
Figure 5: Spores of a Pythium species in root cells of tulip with