I've walked around the garden with more of a purpose than usual lately because I'm on the lookout for any plants with spittle, commonly known as 'cuckoo spit'. It's a sign a froghopper nymph (aka spittlebug) has taken up residence within the protective froth just like you can see in the photo above.
Until recently I'd thought these sap-suckers were relatively harmless, but now I see they're of concern as they're a chief carrier of the bacterium Xylella fastidiosa, which results in the disease and death of many popular garden plants.
It hasn't reached the UK yet and the RHS would like it to stay that way. They've teamed up with the University of Sussex and Forest Research, who need thousands of volunteers - like you and me - to help map the distribution of spittlebugs found in gardens, meadows, grasslands and woodlands from April to late June.
We're being asked to report sightings of spittle, in our gardens or on plants elsewhere, through iRecord. The information needed includes the location the spittle was seen and when, plus the species of plant on which it was found. This information will help researchers understand how Xylella might enter and spread in the UK. So far I've found spittle on my Rosa 'Kew Gardens'; amongst my potted lavenders; and on the perennial cornflowers and Helianthus 'Lemon Queen'.
Xylella is already established in areas of Italy, France and Spain and has resulted in the death of millions of olive trees in southern Italy. Unlike most pests and diseases which are host-specific, Xylella affects more than 500 different plant species with garden favourites such as lavender, oleander, rosemary and flowering cherry all at risk in the UK. The disease prevents water from being transported from the roots to leaves with plants often exhibiting symptoms that can be confused with common problems such as drought or frost damage.
If Xylella is found in the UK, all host plants within 100 metres would need to be destroyed and the movement of specified plants within a 5 kilometre radius would be restricted for up to five years. This would not only be devastating for our gardens it would also put surrounding nurseries and garden centres out of business.
This citizen science project provides a basemap of where the froghoppers are, the plants which nurture them, and how they move around. It will enable researchers to understand the potential impact and put plans in place in case Xylella hops over the English Channel.
Expect to see a ramped up biosecurity awareness programme over the coming months, plus increased measures put in place to prevent pests and diseases from entering the UK. I've seen some of this in action already on my recent visits to Westonbirt as a volunteer, and the RHS has recently revised its plant health policy which applies to both gardeners and the horticulture industry alike. For instance, if you go abroad on holiday, please don't be tempted to bring back plant material, no matter how pretty the plant or how tempted you are.
Further information about the survey and froghoppers can be found here.