Enhancing propagation success & minimising Botrytis in lavender with Romeo

About

Barrett’s Bridge Nursery is based in Cambridgeshire. The nursery specialises in plug plants, supplying hundreds of growers, local authorities, garden centres, landscaping and garden designers across Europe for over 40 years. The plug plant range consists of over 1000 varieties and includes: perennials, shrubs, hardy fuchsias, lavender, clematis, thymes, rockery plants and cottage garden plants.

This case study examines the use of Romeo, an approved biofungicide, during the propagation of lavender cuttings. The aim was to evaluate the efficacy in reducing losses caused by Botrytis and preventing its spread amongst cuttings.

Historically, the grower experienced 15-20% losses due to Botrytis. However, this year, losses were remarkably reduced to around 1%, which is attributed to the use of Romeo.

What is Botrytis and how can it affect your crop?

Botrytis is a common fungus, with its airborne spores always present in the environment. The pathogen can affect all stages of plant growth and often enters via a wound or when the plant is under stress. Fresh cuttings are therefore particularly vulnerable, especially under humid propagation conditions.

Botrytis causes stem dieback and may lead to the eventual collapse of young plants, with fuzzy grey mould covering the decaying tissue. Disease outbreaks can lead to the loss of many young stems and have serious economic implications for the grower.

How can Romeo help?

Romeo is a preventative biofungicide containing the active ingredient Cerevisane, a purified extract of the yeast species Saccharomyces cerevisiae (strain LAS117). Cerevisane mimics a microbial attack, inducing plant defence mechanisms that stimulate the production of anti-fungal compounds and strengthen the plant cell walls and leaf cuticle, protecting the plant from foliar fungal diseases.

As well as protecting ornamental crops against Botrytis, Romeo can also provide defence against powdery and downy mildews. Romeo holds on-label and EAMU approvals for a wide range of crops, across many environments.

Aims

■ To assess the impact of Romeo on reducing Botrytis related losses during lavender crop propagation.

■ To evaluate the efficacy of Romeo in preventing the spread of Botrytis within the tray

Method

■ Lavender cuttings were taken from old stock plants in the week beginning 10^th of April.

■ After 18 days, Romeo was applied to the cuttings. The crop received three subsequent treatments of Romeo at 7-day intervals.

■ The grower discovered minor outbreaks of Botrytis and decided to address the issue by applying the fungicide Amistar (Azoxystrobin).

Despite the appearance of Botrytis on the crop after the initial applications of Romeo, it was effectively managed. The crop exhibited increased resilience against infection, allowing Amistar to work more effectively and prevent the further spread of Botrytis. The grower then continued with regular applications of Romeo to prevent further infections.

Key Findings

■ Reduced Losses Historically, there were 15-20% losses due to Botrytis during the propagation process. However, this year, the losses were only around 1%, indicating a significant reduction.

■ Limited Spread of Botrytis The grower noted that if a cutting did develop Botrytis, it tended to die off without spreading to neighbouring cuttings within the tray. This contrasted with previous years when the disease would quickly spread and impact multiple cuttings.

Observations and Data Collection

The grower closely monitored the progress of the cuttings and recorded any instances of Botrytis.

The use of Romeo during the lavender propagation process resulted in a significant decrease in Botrytis compared to previous years.

Discussion

The observations made suggest that Romeo played a vital role in reducing losses caused by Botrytis and preventing its spread within the lavender cuttings tray.

Conclusion

The implementation of Romeo as a spray during lavender propagation yielded significant benefits for the grower. By reducing losses from 15-20% to approximately 1%, Romeo demonstrated its efficacy in minimising Botrytis-related issues. Moreover, the limited spread of the disease within the tray highlights Romeo’s ability to contain and prevent further dissemination of Botrytis.

By adopting Romeo as a preventive measure during lavender propagation, growers can enhance their success rates, minimise losses, and achieve healthier plant stock, ultimately contributing to the overall productivity and profitability of their operations.

“Botrytis is always present in the environment and disease outbreaks can have serious economic impacts for growers. The use of Romeo within IPM programmes can help to protect crops, prevent the spread of fungal disease and improve plant health.“

Lori-Leah Griffiths, Technical Specialist

“Historically, there were 15-20% losses due to Botrytis during the propagation process. However, this year, the losses were only around 1%, indicating a significant reduction.”

Sean Whitworth, Growing Media and Fertiliser Specialist

“By adopting Romeo as a preventive measure during lavender propagation, growers can enhance their success rates, minimise losses, and achieve healthier plant stock, ultimately contributing to the overall productivity and profitability of their operations.”

Jack Haslam, Technical Development Specialist

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