Lily Of The Valley (Convallaria) Diseases
Gary W. Moorman, Professor of Plant Pathology
| Disease | Symptoms | Pathogen/Cause | Mnaagement |
|---|---|---|---|
| Southern blight | Tan to mustard-colored ball-like structures (sclerotia) on the stem base near the soil. Plants wilt and die. | Sclerotium rolfsii | Remove and destroy infected plants. Apply thiophanate methyl or PCNB to protect healthy plants. |
| Leaf spots and Anthracnose | Small water soaked spots enlarge and turn tan to reddish brown as the leaf yellows | Ascochyta, Cercospora, Mycosphaerella, or Phyllosticta Colletotrichum or Gloeosporium species. | Do not use a sprinkler to water the plants. Wet the soil rather than the plants. Apply pyraclostrobin + boscalid, thiophanate methyl, propiconazole, potassium bicarbonate, Bacillus subtilis to protect leaves not yet infected. |
| Aureobasidium leaf spot | Small water-soaked spots develop which later have brown streaks with yellow halos—these spots often form from the leaf tip downward. Infected leaves die prematurely. | Aureobasidium microstictum | Do not use a sprinkler to water the plants. Wet the soil rather than the plants. Apply pyraclostrobin + boscalid, thiophanate methyl, propiconazole, potassium bicarbonate, Bacillus subtilis to protect leaves not yet infected. |
| Rust | Small yellow leaf spots are on the upper side of the leaf while orange-brown spore masses are on the underside of the leaf. | Puccinia sessilis | Apply thiophanate methyl or Bacillus subtilis to protect leaves not yet infected. |
| Foliar nematode | Areas between the veins turn yellow and then brown. | Aphelenchoides spp. | Water in a manner that keeps moisture off the leaves. Remove and destroy infected plants. |
| FRAC Group No. | Class | Active ingredient | REI Restricted Entry Interval | Trade names (EPA Reg.No.) |
|---|---|---|---|---|
| 1 | Benzimidazole | thiophanate methyl | 12 | OHP 6672 (51036-329-59807) |
| 3 | Triazole | propiconazole | 24 | Kestrel (66222-41-81943) |
| 14 | Aromatic hydrocarbon | PCNB | 12 | Terraclor (400-399) |
| NC | potassium bicarbonate | 4 | Milstop (70870-1-68539) | |
| 11 + 7 | Combined product | pyraclostrobin + boscalid | Pageant (7969-251) | |
| Biological control agent name | Type of organism | Trade Names (EPA Reg. no.) | ||
| Bacillus subtilis | bacteria | Cease (QST 713 strain) (69592-19-68539) |
Fungicide Resistance Action Committees (FRAC) developed a numbering system in which chemicals that have the same mode of action have the same FRAC group number (http://www.frac.info/frac/index.htm). When resistance to fungicides is a concern, it is recommended that you select chemicals to rotate or mix together that have different FRAC Group numbers because then you are using ones with different modes of action.
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Notice: The user of this information assumes all risks for personal injury or property damage.
Warning! Pesticides are poisonous. Read and follow all directions and safety precautions on labels. Handle carefully and store in original labeled containers out of the reach of children, pets, and livestock. Dispose of empty containers right away, in a safe manner and place. Do not contaminate forage, streams or ponds.
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