On the 30th of March 2022, VIRTIGATION partners TECNOVA and AGAPA organized the project’s first multi-actor workshop with stakeholders in Almería. Read our detailed report on the fruiful discussions VIRTIGATION held with key local stakeholders from Europe’s greenhouse capital.
Participation of 30 experts across the value chain
VIRTIGATION gathered more than 30 experts in agriculture, plant pathology and plant breeding from across the value chain. With this workshop, VIRTIGATION research partners and stakeholders from the horticultural sector in Andalusia (Spain) discussed the current situation and the main problems encountered in tomato and cucurbit crops affected by ToBRFV (Tomato Brown Rugose Fruit Virus), as well as ToLCNDV (Tomato leaf curl New Delhi Virus) and its whitefly vectors (e.g. Bemisia tabaci).
During the workshop, two round tables in which participants discussed the topic of “Seeds and plant material” on the one hand, and “Farm management” on the other, were held.
Findings of seeds and plant material round table
In the round table on “Seeds and plant material” it was concluded that the development time for breeding new commercial plant varieties with resistance to viruses is a limiting factor, amounting to periods from 5 to 8 years for cucurbits and 8 to 10 years for tomatoes. These timelines could be significantly shortened with the introduction of gene-editing material produced by CRISPR/Cas9 (i.e. Clustered regularly interspaced palindromic repeats) technology, but this is currently not allowed for commercial purposes in the EU. The option of using public genebanks is a limited resource for private companies due to the delay in public research.
With regard to seed disinfection, the administrative requirement of declaring seeds as “virus-free seed” is considered to be a legal restriction which is not contributing to preventing the spread of viruses. Moreover, there is no test on the market that can guarantee 100% that the seed is free of viruses. This finding, combined with the fact that infection can occur at any time during the process, makes it necessary to trace every step and to homogenise the requirements in all regions. With regard to the most widely used seed diagnosis methodologies, the most important ones are bioassays or PCR and RT-qPCR for their accuracy; the Elisa test for its cost and the digital tools RT-qPCR and PCR for the time needed to obtain the results.
Findings of farm management round table
The round table on “farm management” addressed the management of ToLCNDV at farm level, thus establishing the state-of-the-art of whitefly control. In this regard, the fact that there are hardly any known tomato varieties resistant to this vector and that Bemisia tabaci is the species with the highest incidence in Spain and Italy, compared to Trialourodes vaporariorum, which is most spread in Belgium, stands out. On the other hand, it is determined that crop management, both conventional and organic, has a greater influence on the distribution of the predominant genotype than climate change itself. Likewise, whitefly parasitoids and predators show a distinct preference for genotypes.
This round table also dealt with whitefly control methodologies, identifying two of them as the most common in preventive control: natural enemies, with average effectiveness and farmer confidence, and crop management itself, valued with high effectiveness and average farmer confidence. In terms of treatment methods, the most supported option is the use of bio-based and/or residue-free pesticides, although their effectiveness is rated as medium-low, followed by chemical insecticides, which have high effectiveness and farmer confidence.
Managing ToBRFV on farms
As far as ToBRFV is concerned, it is often identified through external laboratories. The most common measures used for the management of ToBRFV on farms are disinfection, removal of affected plants, prohibition of external visits and application of hygienic measures for workers and tools after use. Within disinfection, solarisation in the case of soil and a series of measures such as the annual change of bags, crop rotation and disinfection with ozone for the substrate, stand out.
In terms of preventing the entry and spread of ToBRFV, a number of practices, considered highly effective by participants, are used. These are hand, glove and tool washing, thorough initial cleaning of the farm, hygiene protocols for clothing and production, and awareness on the use of pesticides. Concerning improving the on-farm control of the virus, VIRTIGATION researchers recommended the implementation of a safe vaccine, resistant varieties and early monitoring systems, as well as increased sharing of measures to farmers, increased research and the implementation of the “quick wins” approach in the application of disinfection protocols, protection measures and management services. And on the farmer’s side, soil hygiene measures, improving the farmer’s own hygiene culture and improving knowledge about virus control, with clearer communication about disinfectants and resistant seeds, were supported.
