On 18 December the 12th meeting of vegetable and ornamental ADVs (plant health advisory groups) was held in Les Franqueses del Vallès, where topics included the introduction of new pests affecting the nursery sector.
1. Acutaspis paulista (diaspidid scale insect)
This is one of the pests with the greatest impact on ornamental plants described in the document.
- Origin and type: An armoured scale insect of South American origin (Brazil, Argentina, Chile). It overwinters as a fertilised female and can have 3 to 4 generations.
- Impact on ornamentals: It is highly polyphagous. In addition to olive trees, it has been detected on ornamental species such as Euonymus japonicus (Japanese spindle) and Ligustrum sp. (privet).
- Symptoms: On ornamentals it mainly affects the leaves. On olive trees it also attacks the fruit.
- Distribution: Detected in Alt and Baix Empordà (municipalities such as L’Escala, Albons, Bellcaire, etc.).
- Control measures:
- In non-agricultural settings (parks/gardens): treatments with pyriproxyfen to reduce the population.
- In general: cleaning of machinery and burning of plant debris.
2. Potexvirus citriflavivenae (citrus virus)
It affects citrus, which are often used ornamentally in private and public gardens.
- Plants affected: Mainly lemon trees (Citrus limon), although also hosts such as Solanum nigrum or Vitis vinifera.
- Symptoms: Symptomatic on lemon trees, but asymptomatic on orange and mandarin trees.
- Transmission: The vectors are mainly aphids (Aphis spp.), as well as the citrus whitefly (Dialeurodes citri).
- Location: First detected in Tarragona (La Galera).
- Measures: Surveys in nurseries and urban allotments, and recommended treatments to reduce the vector population (aphids).
3. Chrysobothris dorsata (beetle on ornamental trees)
- Identification and new detection
- What it is: A beetle of the Buprestidae family. It is an exotic species of Afro-tropical origin.
- New alert (2025): Detected in Parc de la Ciutadella (Barcelona) in November 2025.
- Background: It had previously been detected in Molins de Rei in 2023 on nettle trees (Celtis australis). It is also present in Málaga, Valencia and Murcia.
- Plant species affected
- This pest is expanding its host range:
- Usual hosts: Historically legumes such as Acacia spp. and carob (Ceratonia siliqua). In Valencia it has a preference for citrus pruning waste.
- New host detected: In Parc de la Ciutadella it has been found on Malus spp. (ornamental apple trees, Rosaceae family).
- Co-infection: In this case the insect was found together with the fungus Phomopsis sp.
- Biology and symptoms
- Behaviour: It acts as a secondary parasite. This means it attacks diseased or dead trees, or damaged parts of healthy trees; it does not usually attack vigorous, healthy trees.
- Life cycle: The larvae feed on dead or deteriorated wood under the bark.
- Adults: Characterised by the noticeably serrated side edges of the elytra (hard wing cases). In Catalonia, adults have been observed active during November and December.
- Warning sign: The presence of exit holes in the bark.
- Control strategy
- Control is based mainly on cultural management and plant health, since they depend on dead wood:
- Removal of sources: The main aim is to remove the places where they breed.
- Clean-up: It is essential to remove and destroy pruning waste and any dead woody material, as this is where the larvae develop.
- Monitoring: Active inspections are recommended, especially on ornamental Rosaceae and trees showing signs of stress or weakening
- Tomato viruses (impact on vegetable growing and nurseries)
Although these concern vegetable crops, their management affects nurseries and producers of plant material.
- ToBRFV (tomato brown rugose fruit virus):
- Important change: Since 29/11/2024, under Regulation (EU) 2024/2970, it is no longer considered a pest subject to eradication measures and becomes a regulated non-quarantine pest.
- Prevention: Use of certified material, disinfection of tools and removal of plant debris (incineration).
- ToFBV (tomato fruit blotch virus): Also present, with detections in plantations and nurseries.
5. Drosophila suzukii (spotted-wing drosophila)
It affects berries, but is notable for the new biological control programme.
- Status: Non-regulated pest detected since 2008.
- New in control: A release programme has begun for the parasitoid Ganaspis kimorum, which is highly specific to D. suzukii.
- Release areas: It is released in areas with a high incidence of the pest and low pressure from plant protection product use.
Summary of recommended general measures
The document stresses hygiene and prophylaxis as the key tool:
- Purchase of young plants from authorised operators.
- Constant disinfection of tools and footwear.
- Waste management by burning or incineration.