Thuja occidentalis, a vulnerable plant in need of protection

The Thuja occidentalisThe cedar, or more commonly the cedar hedge, is the plant of choice in urban environments. Mainly used as a vegetative screen or as a property boundary, cedar hedges can also encounter problems with pests.

A pest is an insect, mite or infectious disease such as a virus, bacteria, fungus or mycoplasma. In general, a pest will "attack" a plant, i.e. feed on it, when it is weakened by one or more factors that predispose it to decline. This natural balance, i.e. systematically attacking the weakest, is however destabilized during an epidemic.

Why are there problems in the cedar hedge?

A tree, or a cedar hedge, weakened by one or more factors that predispose it to dieback will, after a while, show visible symptoms: discolored leaves, dead branches, loss of leaf mass, etc. The first step is to provide ideal environmental conditions for your hedge to avoid predisposition to external pests. The first thing to do is to provide the ideal environmental conditions for your hedge to avoid predisposition to external pests. Never treat a pest without first solving the problems associated with the proper development of your cedar hedge in terms of air, water and nutrients.

Who and what are the pest problems?

Spider mites are small red spiders that feed on the sap of foliage, drying out the leaf mass. In periods of infestation, a fable impact or biopestide acaricide will be effective.

Thuja leafminers are the larvae of a minor insect that feeds on the leaf contents of your hedge, drying out its leaf mass. In periods of infestation, a fable impact or biopestide insecticide will be effective. There are also Thuja weevils, bugs, Diprions and lecanias, but these insects are not much of a problem.

Poor irrigation often leads to the development of fungal diseases such as needle blight, phomopsis blight and gray mold, which attack vegetative parts such as foliage, new shoots and flowers.

As adults, cedars need sun all day long. A lack of sunlight will cause the foliage to lose its beautiful green color and dry out. An excess of nitrogen, due to lawn maintenance, can also cause growth problems, darkening the foliage of the lowest branches. It's normal for certain pests to find their way into your cedar hedges. Plants in good health will naturally defend themselves against these invasions. Like us, your hedge is constantly confronted with the problems that populate our environment