Large numbers of Tobacco Whiteflies on Poinsettias – intensified monitoring is necessary

10.11.2006

<div>The tobacco whitefly had spread to at least 45 greenhouses that grow poinsettia in different parts of Finland by the beginning of November. The plant protection inspectors have intensified their inspections of greenhouses and new cases have been found weekly. Evira’s Plant Protection Service believes that not all of the greenhouses troubled by tobacco whitefly have been found yet. Evira is urging the growers to check their poinsettia crops for the whitefly and to report any findings to the local plant protection inspector either at Evira or the TE-centre. </div>

The tobacco whitefly is a harmful organism which is to be eradicated; consequently the authorities determine which control measures to take for the crops. Tobacco whiteflies have been controlled in plant nurseries using both pesticides and biological control agents. The controlling measures have progressed well and the number of whiteflies has decreased. It has been observed however, that the tobacco whitefly is resistant to the pesticides used, which has complicated the eradication. Consequently, the use of pesticides has to be planned to alternate between products containing different active agents.

Growers of poinsettias must check their own crops carefully in order to find the tobacco whitefly. The control will be more efficient if yellow sticky traps are put out. It is also worth keeping the poinsettias separate from other plants in order to prevent the spread of the whitefly. At the end of the poinsettia season, at the latest, there is reason to conduct a thorough clean-up and to destroy all of the remaining poinsettias in order to eradicate any tobacco whiteflies.

For more information please contact: Senior Inspector Olli Elfving, tel. +358 20 77 25048

Finnish Food Safety Authority Evira, Plant Protection Unit

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