by Alan Stewart, Claire Harkin and Vinton Thompson, The Conversation
Since 2013, over 20 million olive trees in Italy have succumbed to a devastating plant disease. The same disease now threatens many more plant species, across several countries, with the same fate.
Our recent research shows that the insect responsible for inadvertently transmitting the bacteria that cause this disease can feed on a vast number of different plant species. These include many herbaceous plants and trees that are commonly grown in gardens, parks and across the wider countryside in Britain.
During spring, gardeners will often wonder why blobs of spit-like foam have suddenly appeared on their favorite plants. Many will think them unsightly, perhaps even taking time to wash them off, only for the foam to appear again the next day.
This "spittle" is produced by an insect, unimaginatively called a spittlebug, whose juvenile stages immerse themselves in the foam in order to stop drying out and to protect themselves from predators.