Fern Diseases
Gary W. Moorman, Professor of Plant Pathology
| Disease | Symptoms | Pathogen/Cause | Management |
|---|---|---|---|
| BACTERIAL BLIGHT Asplenium, Bird's-Nest Fern | Translucent spots develop all over the leaves, enlarge quickly and turn reddish-brown with purple halos. | Pseudomonas cichorii or P. gladioli | Purchase plants free of the disease. Avoid overhead watering. Discard infected plants. |
| GRAYING Nephrolepsis, Boston fern | Leaves have a gray color and plants have few runners. | Drought | Maintain even soil moisture at all times. Examine roots for nematode and root rot symptoms. |
| FOLIAR NEMATODE Asplenium | Small dark green spots form at the base of fronds. Spots turn brown to black as they enlarge. | Aphelenchoides fragariae | Discard infected plants. Avoid wetting the fronds when watering. |
| FROND LOBING Asplenium | Fronds have many lobes and indentations. Frond tips may be crinkled or dead. | Over-fertilization | Reduce the amount of fertilizer being used and leach the pots. |
| LEAF TIP BURN | Tips of fronds and leaflets brown and die. | Over-fertilization | Reduce the amount of fertilizer being used and leach the pots. |
| NEMATODES | Foliage grays, wilts, and dies. Roots are rotted. | Pratylenchus | Pot in pasteurized potting mix. Discard infected plants. |
| PYTHIUM ROOT ROT | Plants have a gray color or are yellowed, stunted, and wilted. Roots are brown and rotted. | Pythium | Plant in pathogen-free pasteurized potting mix. Apply potassium salts of phosphorus acid, etridiazole + thiophanate methyl to protect plants. |
| RHIZOCTONIA BLIGHT | Brown, irregularly shaped spots form on the foliage close to the crown or sometimes at the top. Spots spread very rapidly. Webbing of the fungus forms from frond to frond. | Rhizoctonia solani | Plant in pathogen-free pasteurized potting mix. Apply thiophanate methyl, fludioxonil, or flutolanil as a heavy, drenching foliar spray or chlorothalonil as a spray. |
Active Ingredients and Trade Names of the Chemicals
| FRAC Group No. | Risk Level | Class | Active ingredient | REI Restricted Entry Interval | Trade names (EPA Reg. no.) |
|---|---|---|---|---|---|
| 1 | 3 | Benzimidazole | thiophanate methyl | 12 | 3336 (1001-69), OHP 6672 (51036-329-59807), Fungo Flo (51036-329-59807), Systec 1998 (48234-12) |
| 7 | Anilide | Flutolanil | 12 | Contrast (45639-208-58185) | |
| 12 | 2 | Phenylpyrol | fludioxonil | 12 | Medallion (100-769) |
| M | 1 | Chloronitrile | chlorothalonil | 48 | Daconil (50534-9), Exotherm Termil (70-223) |
| 12 | Echo (60063-7), PathGuard (60063-7-499), Concorde (72167-24-1812), Pegasus (72167-24-1812) | ||||
| U | 1 | Phosphite | phosphorus acid salts | 4 | Alude (71962-1-1001) |
| potassium phosphate | 4 | Vital (42519-24) | |||
| Combined products | 1 | ||||
| 1 + M | thiophanate methyl + etridiazole | Banrot (58185-10) |
Fungicides and Fungicide Resistance Management - Certain fungicides, usually systemic fungicides, are said to be 'at risk' to the development of resistance if they are used repeatedly. See the Risk Level in the above table (1 = low risk; 3 = high risk). The Fungicide Resistance Action Committee has developed a numbering system in which chemicals with the same FRAC Group number have the same mode of action (See http://www.frac.info/frac/index.htm ). It is recommended that chemicals at high risk be used sparingly and in rotation or mixed with chemicals with different modes of actions (different FRAC number).
DISCLAIMER
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.
Issued in furtherance of Cooperative Extension work, Acts of Congress, May 8 and June 30, 1914, in cooperation with the U. S. Department of Penn State College of Agricultural Sciences research and extension programs are funded in part by Pennsylvania counties, the Commonwealth of Pennsylvania, and the U.S. Department of Agriculture.
Visit Penn State Extension on the web at extension.psu.edu.
Where trade names appear, no discrimination is intended, and no endorsement by Penn State Cooperative Extension is implied.
This publication is available in alternative media on request.
The Pennsylvania State University is committed to the policy that all persons shall have equal access to programs, facilities, admission, and employment without regard to personal characteristics not related to ability, performance, or qualifications as determined by University policy or by state or federal authorities. It is the policy of the University to maintain an academic and work environment free of discrimination, including harassment. The Pennsylvania State University prohibits discrimination and harassment against any person because of age, ancestry, color, disability or handicap, national origin, race, religious creed, sex, sexual orientation, gender identity, or veteran status. Discrimination or harassment against faculty, staff, or students will not be tolerated at The Pennsylvania State University. Direct all inquiries regarding the nondiscrimination policy to the Affirmative Action Director, The Pennsylvania State University, 328 Boucke Building, University Park, PA 16802-5901; Tel 814-865-4700/V, 814-863-1150/TTY.
