Thaumatotibia leucotreta, commonly known as the False Codling Moth (FCM), is a threat to the production and marketing of roses, especially in Sub-Saharan Africa. This article was published in the July-August 2021 edition of FloraCulture International magazine. It outlines four crucial Integrated Pest Management (IPM) interventions against this dreaded pest, written by Dr Lisbeth Riis, CEO at Scarab Solutions.
The highly polyphagous False Codling Moth is a major phytosanitary concern for rose growers. It reduces the yield and quality of the crop and, as a quarantine insect pest, restricts the global trade of cut roses.
FCM is currently the leading cause of interceptions in cut flowers exported to the European Union. In 2019, the Dutch National Plant Protection Organisation (NPPO) and the European Union (EU) found that the number of FCM interceptions on Kenyan roses remained over 30, leading to the categorisation of FCM species as quarantine pests. Under further pressure to reduce interceptions by the end of 2021 or risk an increase in checks to 50 or 100 per cent of all imports, rose growers must turn to an effective IPM solution to combat the destructive pest.
Dr Lisbeth Riis, CEO at Scarab Solutions, has more than 15 years of experience working closely with greenhouse rose growers in Kenya. Here she outlines four control measures that, when combined, can effectively combat the proliferation of False Codling Moth infestations and deliver the high-quality products that international markets demand.
Early signs of FCM are often missed, especially during the larvae stage when all five instars of the pest’s development occur inside the plant. This problem demonstrates why careful direct scouting for early indicators of pest presence in the crop is critical, and growers can swiftly apply intervention measures when population sizes are still small. Scouts should monitor for any of small holes, brown spots, or dark brown frass on rosebuds.
During the adult moth life stage, FCM is most active during the night. FCM-specific pheromone traps can make up for this lack of visibility by identifying areas of high concentration that require immediate attention.
Growers can also use dispensers loaded with a high density of synthetic female pheromone to disorientate adult male moths and disrupt mating efforts to keep population sizes at a manageable level.
As FCM are poor flyers, dispersal is usually limited to a maximum of several hundred meters from the original host plant, and they take time to colonise and settle in a new host crop. The first detections are an ideal time to intervene further with targeted control in infestation hotspots.
Biopesticides such as Beauveria bassiana (e.g. Botanigard) and Bacillus thuringiensis (e.g. Dipel DF) are recommendable. Pesticides such as Methoxyfenozide and Spinetoram provide similar results – but it is essential to alternate different modes of action to avoid the development of pesticide resistance.
Paper-based analysis and personal knowledge remain standard features in pest management strategies – yet they can limit the scope of FCM controls, especially when growers must cover multiple greenhouses. However, user-friendly digital maps can provide a quantified insight into the spatial distribution of the pest and the risk zones across the entire farm – allowing growers to make data-based decisions when it comes to early quality control measures.
For instance, digital maps can highlight the number of FCM captured in pheromone traps and guide sprayers to specific areas that require targeted sprays immediately. This quick action can reduce the risk of interceptions, focus resources on key areas and limit waste – allowing farm managers to become more targeted, timely and efficient in their overall management of FCM.
Disrupt the FCM lifecycle with effective IPM at every stage
If significant FCM interceptions continue to persist into 2022, rose growers risk huge losses and tarnished reputations. An IPM strategy, supported by a reliable scouting and mapping system, can overcome this phytosanitary challenge.
Growers can combine targeted and effective early intervention controls to break the pest’s lifecycle – and not only prevent a costly outbreak but also secure a long-term reputation in international markets with high-quality rose products that are FCM-free.
1 Mutyambai, D.M., Mbeche, N.I. and Onamu, E. et al. (2020) False codling moth, Thaumatotibia leucotreta (Meyrick) a new threat to horticulture industry: Stakeholders’ perspectives on the status, impact and management in Kenya. J Plant Dis Prot, 127: 799–804.
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4 Ostojá-Starzewski, J. C. et al. (2017) DEFRA Plant Pest Factsheet, False Codling Moth, Thaumatotibia leucotreta, https://planthealthportal.defra.gov.uk/assets/factsheets/PPN-FalseCodlingMoth-final.pdf
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