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Country focus: Emerging viral diseases in Spain

TYLCV, ToLCNDV and ToBRFV are responsible for emerging viral diseases that threaten the plant health of tomatoes and cucurbits. The horticulture value chain urgently needs to find solutions to address this challenge. Our blog series “country focus” highlights the situation in VIRTIGATION’s focus countries, and how key stakeholders address it. In our third edition, we cover Spain, which is home to the largest concentration of greenhouses in the world.

ToLCNDV and ToBRFV present but kept in check

The Spanish center of tomato and cucurbits  production lies in Andalusía. Andalusía is the southernmost autonomous community in the Spanish mainland. It has a greenhouse area of around 55,000 hectares, of which the majority is located in the province of Alméria. The main crops grown are tomatoes, zucchini, watermelon and peppers. Both Tomato leaf curl New Delhi virus (ToLCNDV) and Tomato brown rugose fruit virus (ToBRFV) outbreaks have affected fields and greenhouses in Andalusía. ToLCNDV first appeared in September 2012 and has caused significant damage to tomatoes and zucchini, but also cucumber and melon crops. This is due to the high transmission rate from its whitefly vector Bemisia Tabaci.

As concerns ToBRFV, its first official infection dates back to November 2019. The Plant Health and Production Laboratory of VIRTIGATION partner  AGAPA (Agency for the Management of Agriculture and Fisheries of Andalusía) detected the first ToBRFV infection in tomatoes. Since then, five ToBRFV outbreaks have been reported, mainly affecting tomatoes and peppers, but without causing significant damage. The latest outbreak occurred in Almería in November 2021, affecting less than 10 hectares.   

Rigorous eradication measures, coupled with traceability studies and continous monitoring and testing have ensured that the incidences of both ToLCNDV and ToBRFV are under control in Spain. According to the European and Mediterranean Plant Protection Organization (EPPO), ToLCNDV and ToBRFV are present in Spain but with restricted distribution and few occurrences. Tomato yellow leaf curl virus (TYLCV) is of no relevance at the moment in the Spanish horticulture sector.   

zucchini affected by ToLCNDV
Example of zucchini plant infested with bemisia tabaci whitefly, the vector transmitting ToLCNDV (©Shutterstock)

Mix of measures recommended to halt virus spread

The Regional Ministry for Agriculture, Livestock, Fisheries and Sustainable Development of Andalusía (CAGPDS), through its Plant Health Service, has established a set of vector control measures for growers to follow in tackling ToLCNDV. Hygiene measures include the use of healthy plant material with a plant health passport and more intensive cleaning of plant debris and weeds in greenhouses and surrounding areas after the end of cultivation. Among the structural measures, CAGPDS recommends that the greenhouses cover should be made tighter, with insect proof meshes on the bands and ridge, skirts on greenhouse bands, a thermal blanket around the perimeter or over the entire cultivation area and the implementation of double doors. CAGPDS also advises continuous biological control with specific chemical treatments.

As concerns the mechanically transmitted ToBRFV, CAGPDS recommends control measures primarily based on prophylaxis and hygenie, in line with EU regulations.  This includes replacing or disinfecting  plastic mulch, and disinfecting irrigation systems and greenhouse structures once the crop is finished. It also advises to regularly disinfect of hands and work tools before and after use, and to forbid entry of staff from outside the greenhouses. 

Value chain united in tackling ToLCNDV and ToBRFV

In Spain, the VIRTIGATION partner AGAPA is the National Knowledge Broker for the country’s multi-actor approach in the project. Alongside its important role in raising awareness and communicating and disseminating information about the viruses, its Production and Plant Health Laboratory located in Almería has been key in researching and diagnosing plant diseases. Next to AGAPA, severeal other crucial actors, from monitoring services, agri-research centers to growers organizations, have been involved in tackling the threat posed by ToLCNDV and ToBRFV in Andalusía.    

The Phytosanitary Alert and Information Network (RAIF) gathers data in the field and offers regular information to help identify and control plant pests and diseases. RAIF monitors the incidence of pests and diseases of different crops on a weekly basis, including on ToLCNDV and ToBRFV in fruits and vegetables. The public institute for Agricultural and Fisheries Research and Training in Andalusía (IFAPA) has been important in supporting growers and value chain actors with its research, training, technology development and transfer activities. Its trainings on the use of biocontrol and proper crop management have been fundamental in transforming intensive horticulture to address the whitefly-transmitted ToLCNDV in particular. Furthermore, IFAPA conducts trials to evaluate IPM-compatible plant protection products and researches e.g. for resistance to ToLCNDV in melons. 

Growers supporting virus detection efforts

The Association of Fruit and Vegetable Producers’ Organisations of Almería (COEXPHAL) is a organization representing growers that accounts for around 2/3 of fruit and vegetable production and 70% of exports. It has played a key role for example in organising dissemination conferences on production techniques, promoted biocontrol methods and draw up informative guides on emerging viral diseases affecting the horticulture value chain in Andalusía. Thanks to its efforts in spreading knowledge and raising awareness on ToLCNDV and ToBRFV, growers themselves have detected the latest virus outbreaks in Andalusía. Thereby, they have helped Plant Protection authorities in acting more effectively in tackling and controlling these viruses.