Easter Lily Diseases
Gary W. Moorman, Professor of Plant Pathology
|BULB BASAL ROT||The basal plate is dark brown and dead. Scales fall off.||Fusarium and Cylindrocarpon||Use pasteurized potting soil. Do not plant bulbs that have a rotted basal plate. Dip bulbs in a fungicide before planting.|
|BULB STORAGE ROT||Bulb scales have brown spots and a severe rot. Bulbs may be soft and covered with a blue-green mold or white fungal growth.||Bulbs harvested while still immature are attacked by Penicillium (blue mold) or Rhizopus (soft rot) fungi.||Do not plant affected bulbs.|
|BOTRYTIS BLIGHT||Oval to circular reddish-brown spots form on leaves. Brown spots develop on flowers.||Botrytis cinerea||Maintain humidity below 85%. Apply a fungicide to protect healthy plants.|
|LEAF SCORCH||Semicircular dead areas develop along leaf margins and may engulf leaf tips.||Uncertain. Fluoride toxicity, mineral deficiency induced by root rots, and low soil pH have been implicated in scorch.||Avoid the use of superphosphate and other fluoride-containing fertilizers. Control root rots. Maintain a soil pH between 6.0 and 7.0.|
|PYTHIUM ROOT ROT||Lower leaves yellow and die. Roots are limp and dark brown. Flowers abort.||Pythium||Use pasteurized potting soil. Drench potted bulbs with a fungicide. Or, apply a fungicide as a soil drench.|
|RHIZOCTONIA STEM ROT||Bulbs are yellow rather than the normal white. Stems and scales where the stem emerges develop a soft rot, causing the plant to topple.||Rhizoctonia||Use pasteurized potting soil. Drench potted bulbs with a fungicide. Repeat treatment as stated on the fungicide label.|
|SCALE TIP ROT||The tips of scales turn tan or dark brown to black in color.||A complex interaction of Pseudomonas bacteria and the fungi Fusarium and Cylindrocarpon appear to be the cause.||Do not plant affected bulbs.|
|TWIST||Leaves along the middle stem area twist while leaves above and below appear normal.||Uncertain. Pseudomonas may be involved.||None|
|CURL STRIPE||Plants emerge later than normal. Soon after emerging, leaves twist and have white stripes. Tops are crooked. Mildly affected plants grow on and appear normal except for the lower leaves.||Lily symptomless virus (LSV)||No chemicals control a virus. Maintain greenhouse aphid free since LSV is carried by aphids from plant to plant.|
|FLECK||Short white lines develop on the leaves. Entire plant and flowers are stunted.||Cucumber mosaic virus (CMV) in combination with LSV||No chemicals control a virus once disease has begun. Maintain greenhouses aphid-free since CMV and LSV are carried by aphids from plant to plant.|
Rhizoctonia stem rot.
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