On 25 September, VIRTIGATION partner Proefcentrum Hoogstraten (PCH) organised our 7th webinar on Bemisia tabaci, whitefly and ToLCNDV plant virus control.
Practical results from VIRTIGATION to fight Bemisia tabaci and other whiteflies
The seventh VIRTIGATION lunchtime webinar brought together 25 out of 44 registered stakeholders. The audience included mainly Dutch-speaking Belgian stakeholders of the VIRTIGATION network. It included seed companies, crop protection actors, growers, technical advisors, journalists, laboratories, plant scientists, as well as official plant protection services.
The aim of this online event was to inform Belgian Dutch-speaking plant health stakeholders on practical results in combating whitefly. Lise Soetemans from PCH gave first an introduction on the differences between Bemisia tabaci and Trialeurodes vaporariorum. Not all Flemish growers are familiar with these differences and sometimes mistakenly identify Bemisia tabaci as Trialeurodes vaporariorum, although the IPM strategies for each species differ.
ToLCNDV not yet present in Flanders
Then, PCH gave an introduction to ToLCNDV. This virus is not yet present in Flanders and is therefore relatively unknown. PCH explained to webinar attendees the relevance of the virus and the associated threat.
Moreover, Lise Soetemans from PCH presented some project results from partners that are relevant to growers, such as the impact of global warming on the spread of Bemisia tabaci and ToLCNDV, and the different host plants for the virus.
Trials in VIRTIGATION on whitefly control
Next, PCH described its trials on whitefly control in more detail. They performed two greenhouse trials in a 500 m² greenhouse on mature production tomato crops. The first trial focused on two biological plant extracts provided by VIRTIGATION coordinator KU Leuven, which have insecticidal effects. The compartment had a natural Trialeurodes infection with some hotspots that posed a risk to qualitative production, necessitating a curative treatment. Over a 4-week period, with one treatment per week, both extracts showed a positive effect on the whitefly population, causing a significant decrease. The extracts performed better than the chemical and biological controls. In addition to Trialeurodes, Macrolophus pygmaeus was also present in the greenhouse, and PCH could not observe any effect of the extracts on the Macrolophus population.
The second PCH trial focused on natural resistance of tomato plants, specifically the role of trichomes in the fight against Bemisia. This trial included a tomato cultivar provided by VIRTIGATION partner WUR with enhanced trichome development. PCH inoculated the greenhouse with Bemisia tabaci. Results indicated that this cultivar had a highly significant impact on Bemisia survival. Compared to a commercial variety, population development was greatly delayed.
Valuable insights for Belgian growers
In conclusion, the webinar provided valuable insights into effective whitefly management and the emerging threat of ToLCNDV for Belgian tomato growers and other stakeholder. The PCH trials demonstrated promising approaches for both curative and preventive strategies, including the use of biological plant extracts and cultivars with natural resistance traits. These findings underline the importance of integrated pest management, careful monitoring, and continued research to safeguard tomato production in commercial greenhouses.
More on the topic of whiteflies and viruses in a changing climate:
- Recording of the VIRTIGATION lunchtime webinar (in Dutch) on YouTube
- Presentation by Lise Soetemans from VIRTIGATION partner PCH
