Verticillium Wilt (Verticillium spp.)
GDD Window (base 50): 306-1370
Overview:
- Verticillium albo-atrium or Verticillium dahlia
- Soil-borne fungal pathogen that can remain in the soil for up to seven years once infested (i.e. persistent)
- Can overwinter as microsclerotia in the soil
- Prefers cooler weather and drier soil
- Can be more severe in neutral to alkaline soils
- Can be harbored by MANY weeds
- Symptoms vary between hosts
- Symptoms may occur on branches scattered over the entire tree, or may be confined to one side
- Often first observed during periods of drought stress during summer/early spring due to fall/winter drought
- Can cause sudden wilting and yellowing of leaves, leaf scorch, leaf browning, and early death and dropping of leaves
- Can cause branches to fail to leaf out in the spring, or sparse or undersized leaves
- Can cause death to part or all of a plant (can’t sell)
- Results in discoloration of xylem, as xylem gets clogged up and is unable to transport water
- Green, brown, or black streaks may be present when bark is peeled away from the impacted branches
- Visual symptoms alone are insufficient for diagnosis – submit samples to diagnostic lab to verify
- Host plants: over 400 species
- Common: Maple, redbud, ash, cherry, smokebush
Management:
- No highly effective treatments – prevention is key
- Get appropriate diagnosis – ID is critical
- Crop rotation to less susceptible varieties in known infested locations
- Do not over fertilize (stress) and keep irrigation on ‘drier side’
- Rouge symptomatic plants to reduce the spread of the disease.
- Symptomatic branches:
- Nursery/greenhouse: indicative of longer-term root / vascular tissue infections = rouge plants out
- Landscape: Prune and destroy symptomatic branches, making sure to sanitize pruners between cuts
- Can apply high N-fertilizer to promote plant growth but just prolonging the inevitable
- Soil treatments:
- Fumigation /solarization can reduce the pathogen in the soil
- Removal of soil / evaluation of media
- Sanitation of infested production equipment: avoid spread it & avoid putting tree back into infested socket-pots
Disclaimer – Materials do not cover all possible control scenarios and are intended for licensed professionals. Tradenames do not imply endorsement and are used as examples. You must strictly follow the label for each compound prior to use. Rutgers is not responsible form is used materials or damages thereof. The label is the law. Labels will provide detailed information on use and restrictions. Additionally, application intervals, compatibility, surfactant use, PHI, PPE, important and other key information is described in detail. Always discuss treatments with your local agents. Note: Neonicotinoids can only be legally applied in commercial agriculture settings by licensed applicators. Guidelines and recommendations made in this presentation are specific to the state of New Jersey.