Millions of poinsettia cuttings are imported each July into the UK from overseas for British nurseries to grow on into full-sized plants for the festive season.
But this year Bemisia tabaci, the tobacco whitefly, hit young plants in Germany, meaning they could not be sent to the UK. While the whitefly is relatively common on the continent, Britain is a protected zone against the pest, meaning there are tight restrictions to stop it establishing here.
The Department for the Environment (Defra) recently issued a pest alert to raise awareness of ongoing problems with Bemisia tabaci and poinsettias.
Defra said: “The pest is frequently intercepted on ornamentals in the UK and in 2018 there has been a higher than usual incidence on Poinsettias grown in other parts of Europe, leading to cancellations of deliveries and growers in the UK suffering from shortages. Bemisia tabaci can cause direct damage by feeding and indirect damage through honeydew egestion. However, the viruses vectored by the pest have the greatest impact and can cause total failure of susceptible crops.” Growers were told to consider carefully sourcing poinsettias to protect their business and others by only using reputable and authorised suppliers of Poinsettias.
The festive plants are available in garden centres and nurseries now. But stocks may have been compromised by the outbreak and plants are expected to sell out faster than usual.
Poinsettia breeder Dummen was unable to supply its usual two million cuttings this season – some 70% of the market – because of bemisia outbreaks, telling customers on 29 June that cuttings would not meet UK Plant Health requirements.
As a consequence UK growers had to look elsewhere, for instance to Beekenkamp, Selecta and Syngenta.
Deliveries were delayed for around three weeks to many growers.
Bemisia tabaci (tobacco whitefly) is a pest of a wide range of plants, including vegetables, salad crops and ornamentals, and is a vector of more than 110 viruses. It is unlikely to establish outdoors in the UK, but outbreaks can occur in protected crop situations.