Phytophthora cinnamoni, Phytophthora citricola, Phytophthora cryptogea is the most dangerous disease of coniferous trees, shrubs and heather plants.It is very common to see its symptoms in rows, for example in thuja, rhododendrons and azaleas, and recently also on blueberries.The first symptom of phytophthora is clearly stunted growth.
Then the shoots change color and then gradually die. The needles begin to turn yellowish and then turn light brown and ash.It is similar with the leaves of deciduous plants.A characteristic feature of phytophthora is initially the dieback of only single shoots.On rhododendrons, the leaves curl along the main nerve, hang down, and when shaken a suspicious shoot - they do not fall.
To make sure your plant is attacked by phytophthora, a simple test can be carried out. Cut off the bark at the base of the infected plant with a sharp instrument.If the color of the wood is rusty red, it is a sign that the plant is infected by the fungus species that cause phytophthora.Such a plant is practically impossible to save. A bush or a tree should be dug up immediately with the root ball, because it will be a source of infection for neighboring conifers, as well as for rhododendrons and azaleas.
Autumn planting of trees and shrubs
The site of the infected plant should be decontaminated with a fungicide.The biological preparation Polyversum can also be used.It contains the fungus organism Pythium oligandrum. It is a non-pathogenic species that is a parasite of the fungi that cause diseases such as the described phytophthora and gray mold, rot rot, scald rot and many others that infect vegetables, strawberries and ornamental plants.
