The whitefly Bemisia tabaci has been a serious pest in protected tomato crops since 1995 in the south of Portugal (Algarve), causing severe losses mainly resulting from Tomato yellow leaf curl virus (TYLCV), first reported in the autumn/winter season. In order to manage and control the B. tabaci/TYLCV complex, experimental field trials were carried out between 1997 and 2000. Several control methods were tested, such as the application of white screen nets to windows and doors, chemical treatments against B. tabaci and the use of cucumber as a trap crop. The results show that the percentage of plants with TYLCV symptoms mainly reflects B. tabaci infestation level in the first 6 weeks. Screen net protection was the control method that clearly provided a low incidence of plants with TYLCV symptoms in the autumn/winter season. Additionally, insecticide treatments, made weekly in the first 6 weeks, may give improved protection. In the winter/spring season, the B. tabaci/TYLCV complex is a minor problem because of the low populations of B. tabaci and the climatic conditions. Information about the work in progress and results was given to growers through visits to the experimental fields and oral presentations.

The whitefly Bemisia tabaci has been a serious pest in protected tomato crops since 1995 in the south of Portugal (Algarve), causing severe losses mainly resulting from Tomato yellow leaf curl virus (TYLCV ), first reported in the autumn / winter season. In order to manage and control the B. tabaci / TYLCV complex, experimental field trials were carried out between 1997 and 2000. Several control methods were tested, such as the application of white screen nets to windows and doors, chemical treatments against B. tabaci and the use of cucumber as a trap crop. The results show that the percentage of plants with TYLCV symptoms mainly reflects B. tabaci infestation level in the first 6 weeks. Screen net protection was the control method that clearly provided a low incidence of plants with TYLCV symptoms in the autumn / winter season. Additionally, insecticide treatments, made weekly in the first 6 weeks, may give improved protection. In the winter / spring season, the B. tabaci/TYLCV complex is a minor problem because of the low populations of B. tabaci and the climatic conditions. Information about the work in progress and results was given to growers through visits to the experimental fields and oral presentations.

According to EU and Portuguese law, inspection of horticultural nurseries is an important task for the Phytosanitary Inspection Services of the NPPO, which requires the introduction of some rules: official registration of producers and production of plant material of EC quality. Mainly as a result of the introduction of Tomato yellow leaf curl virus (TYLCV) in 1995, tight control of registered nurseries was implemented in Algarve in order to ensure the production of young horticultural plants of good varietal and phytosanitary quality. A survey system was established in order to contain pests by trying to eradicate them in nurseries. Nurseries were obliged to adopt new technologies, including for example the compulsory use of screen nets, the improvement of the existing glasshouses and the implementation of strict rules for access of people to these places. The Administration (MADRP/DRAALG) has provided financial support in order to have new nursery glasshouses (without increasing the area) suitable for the control of Bemisia tabaci and other pests which may be disease vectors. It should be stressed that about 50% of nursery production in Algarve is used in other regions of Portugal, considered as EU Protected Zones for B. tabaci.