Xyella fastidiosa – a ‘game changing’ disease

xylella-olivi

There has been a small flurry of media reports over the past few months about what has been reported as a ‘game changing’ plant disease that threatens commercial horticulture in the UK.

Xyella fastidiosa is endemic in America but until a few years ago wasn’t known to be present in Europe.  Then in 2013 whole olive groves in southern Italy were being wiped out and Xyella fastidiosa was discovered to be the culprit. It was later found  in Corsica and mainland France.  Centuries old olive groves have been destroyed by the disease.

It works through infecting the water carrying systems within the host plant – the xylem- (hence its name) spreading via insects that feed on the xylem such as leafhoppers and spittlebugs. It inhibits the transmission of water and nutrients through the plant which is ultimately starved to death.  Its visible symptoms include things like necrotic leaves, leaf scorch, wilt and drop which are indistinguishable from other diseases making it tricky to spot.  If found in the UK host plants within 100m would be destroyed and there would be restrictions on movement of plants within a 5km radius for five years – obviously causing considerable problems for surrounding nurseries and garden centres.

Experts believe that it’s most likely to appear in the UK via the importation of infected plant material rather than via insects and as a result commercial growers and retailers are likely to spot it first. As a precautionary measure the RHS will this year only allow British-grown hebe, rosemary, lavender, oleander, olives, polygala, coffee, Spanish broom and prunus at its shows including the prestigious Chelsea Flower Show.

Xyella fastidiosa has a wide range of host plants and a comprehensive list can be found here. 

One means by which to restrict the chances of the disease reaching these shores and then spreading is to support local growers. The shorter the distance a plant has to travel the better for the environment, the less chance there is of disease spreading. What’s more you get to support good local businesses run by people who are passionate about what they do.