Key Features
- Crown rot
- Root rot
- No vascular discoloration
Symptoms
Crown rot describes decay of the plant at the soil line by a soil-borne pathogen, and is caused by a variety of fungal and pseudofungal pathogens. Destruction of vascular tissue results in discoloration and wilting of leaves, leaf drop, and blight. Eventually, the plant will die. The pathogen spreads up the stem as the host weakens. Send samples to a plant disease diagnostic lab for a conclusive diagnosis of any root or crown rot before attempting control measures. Contact the lab for information on what material to submit.
Biology
Fusarium is a ubiquitous soil fungus, and can successfully infect when provided the proper environmental conditions and/or a wounded host. The disease progresses up the stem from the site of infection. Succulent stems may be girdled by the disease, while woody stems and trunks have isolated, spreading cankers.
Management Recommendations
Disease prevention must be the primary goal as fungicides cannot "cure" these diseases. When planting and working in the landscape, take care to not damage the crown or roots of any plants. Plant to avoid infection. Choose sites well suited to the plants' soil, sunlight, and water requirements, and avoid areas with a history of problems. Irrigate and fertilize as necessary to reduce plant stress. Anything that spreads contaminated soil (such as workers, run-off, pets, and insects) effectively spreads soil-borne pathogens. Inspect plants for symptoms prior to purchase to decrease the chances of introducing the fungus to new plantings. Always remove infected plants as soon as possible to prevent inoculum from building in the soil. Replant with non-hosts, as even resistant varieties can be killed if inoculum levels are high. Varieties of some ornamentals are more resistant to certain crown rot pathogens. Consult a local nursery or arborist for more information.
Effective Pesticides
Active Ingredients include: Thiophanate-methyl
Resources
- Not satisfied with ID? Contact the Purdue Plant and Pest Diagnostic Lab
- Sign Up for the Purdue Landscape Report
