KAURI DIEBACK DISEASE Commonly known as PTA (phytophthra taxon Agathis). Symptoms. Yellowing of foliage, Canopy thinning, Dead branches, Trees can develop lesions that bleed resin, extending to major roots and sometimes girdling the trunk as “collar rot”. Can kill trees and seedlings of all ages. There is a number of simple ongoing steps that you can take to minimize the risk which are: Minimise movement around kauri tree roots. Keep dogs and other animals away from kauri trees. Ensure that any implements and tools that you are using around the … Continue reading Kauri Dieback