The vigilance required in commercial horticulture has reached a new level following a critical observation regarding Tomato Brown Rugose Fruit Virus (ToBRFV). Previously identified as a severe threat primarily to tomato and pepper crops, this aggressive Tobamovirus has now been discovered naturally infecting chrysanthemum (Chrysanthemum indicum) plants in European greenhouses, specifically in Sicily. Symptoms noted in the affected chrysanthemums included leaf deformation and interveinal discolouration. This finding underscores an alarming risk, particularly given that chrysanthemum is widely propagated through cuttings, increasing the potential for rapid and widespread transmission across ornamental production.
Managing ToBRFV hinges entirely on stringent prevention and hygiene protocols. This virus is exceptionally stable, capable of persisting and remaining infectious for months on various surfaces throughout the greenhouse, including tools, soil, organic residues, plastic, and glass. Its primary route of spread is mechanical transmission—meaning human activities, such as pruning, handling, and the movement of equipment and personnel, are the main vectors.
Actionable Guidance: Elevating Your Hygiene Standards
Since no curative treatments exist for infected plants, effective IPM against ToBRFV relies on a disciplined, three-tiered hygiene strategy.
1. Environmental Cleanout and Disinfection
Rigorous sanitation must precede chemical disinfection, as organic matter neutralizes virucidal products.
- Heat Treatment: For materials like irrigation trays, exposure to water heated to 90°C for five minutes is sufficient to inactivate the virus.
- Chemical Disinfection: Effective solutions require sufficient contact time. Proven options include Sodium hypochlorite (bleach) at a minimum of 0.5% concentration for ten minutes, or Potassium peroxymonosulfate (Virkon-type products) at a minimum of 1% concentration for ten minutes. Benzoic acid-based disinfectants like Menno Florades (4%) also demonstrate effectiveness, notably requiring four hours of contact time on steel surfaces at a pH below 4.
- Application Method: Utilizing foam application is recommended as it keeps surfaces wet longer, extending the crucial contact time required for full efficacy, and allowing for better coverage in cracks.
2. Personnel and Tools: Controlling Mechanical Spread
Personnel are the most critical vectors for virus transmission. Implement these measures to mitigate risk:
- Hand Hygiene: Disposable gloves should be used and changed frequently. Hands and tools can be dipped in a solution of skimmed milk powder (minimum 3.5% protein) to form a temporary protective layer against mechanical transmission. Alternatively, non-alcohol-based products like Fadex Rapid are proven effective against Tobamoviruses on hands and tools in only 30 seconds.
- Clothing and Footwear: All specialized greenhouse clothing must be laundered at a minimum of 60°C (95°C is preferable). Disinfect footwear upon entry using disinfection mats containing solutions such as 2% sodium hyrdroxide (NaOH).
- Contaminated Items: Maintain a strict policy against bringing personal items (e.g., phones) into growing areas, as they are easily contaminated.
Invest in Knowledge: Master IPM Strategies
Protecting your high-value crops from persistent threats like ToBRFV requires moving beyond reactive measures toward a knowledge-based Integrated Pest Management system.
To ensure your team is equipped with the latest research and most effective protocols against both pests and emerging viral pathogens, we strongly recommend exploring our specialized professional courses:
- Tomato Brown Rugose Fruit Virus (ToBRFV) : Includes the latest information and enhanced protocols for cleaning and containment.
- Dealing with plant viruses: Provides comprehensive knowledge of viral transmission routes and critical testing methods.
- Monitoring pests and diseases of Chrysanthemums: Focuses on implementing optimal scouting and control integration to enhance crop resilience.
