The European Union classifies the False Colding Moth (FCM) as a quarantine pest. Therefore, stringent measures are put in place to control products exported into member states. The European Food Safety Authority (EFSA) has in the past pointed out roses among the import products that introduce false codling moth into the EU.
Recently, the EU agencies responsible for controlling imports announced that the minimum frequency for roses from Kenya and Ethiopia will increase to 25% effective May 2024. Currently, the identity and physical checks on consignments of roses from Kenya are 10% and 5% for Ethiopia.
The False Codling Moth and the Development Stages
The false codling moth (Thaumatotibia leucotreta) is a pest that threatens many fruits, vegetables, flowers and other crops. It is present on more than 50 host plants including roses, peppers, citrus etc, thus challenging to control.
The false codling moth undergoes four stages of development i.e., egg, larva, pupa and adult. Mated female FCM adult moth can deposit eggs on the surface of a host plant’s fruits (if the plant has fruits), leaves, or flower petals. The eggs are flat and translucent thus difficult to detect.
Once the eggs hatch, the emerging FCM larvae feed and live for 12-65 days. The larvae may burrow into the flower buds, especially in roses or fruits in citrus and other host plants. You can visually detect the larva stages, especially on asymptomatic buds using a hand lens. Opening the buds can reveal the larvae entry and exit points. Besides, the larvae leave dark-brown frass around the opening. At maturity, the larvae exit from these points and fall to the ground to pupate. FCM pupa remains in the soil until they become adult moths.
European Union’s Regulatory Measures
The European Union seeks to stop the introduction and spread of new plant diseases and pests into their member states. This effort helps reduce or eliminate the environmental and economic impact of the organisms and reduce the need for pesticide use. Therefore, the EU requires that every country through its National Plant Protection Organization give a phytosanitary certificate to guarantee that consignments originating from there have undergone proper inspection, are free from quarantine pests and adhere to the EU plant health requirements.
In Kenya, this mandate is under the Kenya Plant Health Inspectorate Service (KEPHIS). In addition to the inspections conducted by a country’s plant protection organization, a certain percentage of the import must undergo another inspection once it lands in the EU market. If there is a large number of consignments intercepted with either pests or diseases, the EU may increase the minimum frequency of checks it does on the imports.
In 2019, the frequency of inspections on consignments from Kenya increased from 5% to 10%. This minimum frequency is now set to increase to 25%. Unfortunately, an increase in the minimum frequency for inspections affects the rose farms in terms of competitive position, costs and time.
Managing the False Codling Moth in Kenya
Below are management strategies for the false codling moth in Kenya:
Cultural Control
Farms should carry out cultural control to avoid the build-up of pest populations over the season. Some of the cultural practices to consider include:
- Monitoring
Farms should regularly monitor their crops for the presence of the false codling moth. Pheromone traps are crucial tools in monitoring. The traps catch only male FCM which indicates the presence of female counterparts. Besides the traps helping to monitor the pests, growers can use them to disrupt the mating or breeding activities on the farm by destroying the trapped males. A shortage in male FCM to fertilize their female counterparts will help reduce the infestation.
- Use Clean Planting Material
The planting material should be free from crown galls. FCM larvae and pupae often use crown galls as sites for development. The pests also hide in the galls making it hard for chemical control measures to eradicate them.
- Maintain Field Sanitation
Orchard sanitation plays a critical role in preventing false codling moth outbreaks in ornamentals. Remove all pruning and crop debris from the field since they may serve as a reservoir for FCM. Infested and damaged plant debris should be disposed of through burying. Farms can also place the crop residues in black bags to allow solarization to occur for up to 48 hours in sunny conditions and later compost the debris. Further, remove galls and solarize them before disposal.
Physical Control
Growers can carry out the following physical measures to control FCM in Kenya:
- Prevent Entry into the Greenhouse
Some of the physical practices that can help prevent the FCM from accessing the greenhouse include fixing fitting doors and always closing them. There should be signs encouraging implementation, e.g., “Please close the door behind you”. Further, farms should install insect screens, shade nets and insect nets to bar FCM moths from entering the greenhouse. Perform immediate repair or replacement when these screens are worn out.
- Destroy the Pests
If there are already pests in the greenhouse, mechanical destruction can help manage them. It can include mechanically picking and killing the caterpillars, eggs and moths. Pheromone traps can also help physically capture the adult male moth as they contain glue.
Biological Control
Farms can prevent FCM outbreaks using naturally occurring egg parasitoids such as Trichogramma cryptophlebiae. Other effective biological control agents include:
- Bacterium
Bacillus thuringiensis var. kurstaki
Bacillus thuringiensis var. aizawai.
- Virus
Cryptophlebia leucotreta granulovirus (CrleGV)
- Entomopathogenic fungal species
Beauveria bassiana
Metarhizium anisopliae
Chemical Control
Farms can use pesticide products registered in Kenya and accepted in the EU market for the control of false codling moths and caterpillars on roses. While using chemical control, always read the user guidelines and use the recommended application rates. Further, note the lifecycle stage of either eggs, larvae and/or adults that the application targets. Note that the FCM moth is quick to develop resistance against chemicals thus you need to alternate several chemicals.
You can consider the following active ingredients to control FCM in Kenya:
- Acephate
- Lambda-cyhalothrin
- Lufenuron
- Emamectin benzoate
An integrated approach across all stages especially the production and packaging stages and the involvement of all stakeholders in the value chain is key to managing false codling moth. Further, the management strategy must involve staff communication, training and use of integrated control techniques. The Kenya Flower Council and KEPHIS have been implementing various measures e.g., training inspectors, scouts and rose growers to manage FCM in Kenya.