Looking for lesions on limes
Can you help? PhD student Helene Kile is researching increasing reports of Tilia (lime) trees with bleeding cankers. If you know of any Tilia trees in the UK showing these symptoms Helene would love to hear from you. Read on to find out more.
Over the past ten years, there have been increasing reports of Tilia species and hybrids with symptoms of bleeding cankers. Although Phytophthora plurivora is suspected to play a role in these Tilia bleeding canker cases, a novel bacterial species, Brenneria tiliae, has also been isolated from sites in Gloucestershire, Wiltshire and Shropshire. Given the devastating environmental effects caused by Phytophthora species and the pathogenic potential of members of the genus Brenneria, either or both of these microorganisms may constitute a new threat to an already deteriorating Tilia population in the UK.
Helene’s project aims to determine the agent(s) responsible for the symptoms, whether these agents can be linked to specific symptoms and the potential threat posed by this previously undescribed disease to Tilia trees in the UK.
What the cankers look like
The cankers typically extend longitudinally, varying in size from only a few centimetres to nearly 2 m. Some trees have several cankers while others have just one and the location on the trunk varies from ground level up to 2.5 – 3 m. Cankers appear moist and sometimes wet with a dark exudate, hence the term bleeding canker. Older cankers can be dry, and stained weep marks from current and previous bleeding episodes have also been observed. The colour of the cankers varies from mid- and dark brown to nearly black. Some cankers have a hint of black-purple while others have a red and rust-brown appearance. The canopies of these trees are not noticeably affected.
How you can help
Have you seen any lime trees with symptoms like these? Helene and her supervisor Carrie Brady would greatly appreciate any reports of Tilia suffering from lesions and bleeding cankers resembling those described so they can arrange for sampling. Please let them know their location, a short description of the symptoms and images if possible. This provides a unique opportunity to get involved and contribute to this important research. You can contact Helene via [email protected] and Dr Carrie Brady via [email protected].