We use some essential cookies to make this website work.
We’d like to set additional cookies to understand how you use forestresearch.gov.uk, remember your settings and improve our services.
When infected with Phytophthora lateralis, a Lawson cypress tree will decline rapidly. Its foliage will first turn to rust-red and then dull bronze over most or all of the crown. Although the pathogen typically attacks tree roots, it can also occasionally attack the stem or branches. Discrete aerial infections produce large, isolated patches of crown foliage that turn bronze or brown.
If you suspect a tree has P. lateralis infection, first confirm the tree species [Link to sub-page on identifying different conifer trees]: brown foliage is common in Leyland cypress for a variety of reasons, but P. lateralis is not known to infect this species.
You can identify infected conifers by cutting away the outer bark at the base of the tree to reveal the phloem or inner bark. Healthy phloem is a cinnamon brown colour, but becomes clearly discoloured following P. lateralis infection.
Cookies are files saved on your phone, tablet or computer when you visit a website.
We use 3 types of cookie. You can choose which cookies you're happy for us to use.
These essential cookies do things like remember your progress through a form. They always need to be on.
We use Google Analytics to measure how you use the website so we can improve it based on user needs. Google Analytics sets cookies that store anonymised information about: how you got to the site the pages you visit on forestresearch.gov.uk and how long you spend on each page what you click on while you're visiting the site
Some forestresearch.gov.uk pages may contain content from other sites, like YouTube or Flickr, which may set their own cookies. These sites are sometimes called ‘third party’ services. This tells us how many people are seeing the content and whether it’s useful.