Volutella Blight of Buxaceae
Overview:
- Caused by Coccinonectria & Pseudonectria spp.
- Specifically, boxwood, pachysandra, and sarcococca
- Mature leaves are more resistant than young leaves
- Warm weather pathogen: 68-77F+, 85%+ humidity is ideal
- Overwinters in boxwood branches, leaves, and plant debris from the previous season
- Symptoms become apparent in spring to early summer
- Growth of branches is delayed, plants show poor vigor
- Stem cankers, girdled stems, dieback (must be carefully pruned)
- Loose bark and discolored bark around cankers
- Straw color leaves stay attached for significant periods (BW)
- Large necrotic & expanding infections in Pachysandra
- In high humidity weather, salmon-colored fruiting structures develop on lower surfaces of leaves (Sporodochia)
- Spores are wet and sticky, traveling only short distances by wind
- Easily transported by humans, wildlife, during propagation
Management:
Cultural Practices:
- Avoid winter injury, poor vigor, and stem wounds
- Prune diseased branches when foliage is dry
- Sanitize pruning tools after working with diseased plants
- Prevent creating further wounds with pruning tools
- Maintain plant health and reduce unnecessary plant stress
- Avoid excess water and fertilization
- Maintain proper air circulation
- Keep area around plants clean, destroy debris
- Choose well drained soil , avoid overhead watering
Materials:
- Contact fungicides:
- Chlorothalonil [M05]
- Mancozeb [M03]
- Coppers [M01]
- Bordeaux mixture
- Systemic insecticides:
- Thiphanate-methyl [1]
- Propiconazole [3]
- Considerations:
- Weight Pros/Cons of using long REI materials. May be worth it in high disease severity instances.
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.