Diseases and Pests of Hamamelis and Their Control

Diseases and their control of Hamamelis virginiana

Two common diseases of witch hazel are leaf spot and anthracnose.

Leaf spot

The main symptoms of the disease are damage to the leaves, petioles and stems. Circular spots appear on the leaves. As the disease progresses, the spots gradually increase in size and deepen in color from reddish brown to dark brown. It is mostly caused by fungi, bacteria, and nematodes.

Prevention and control methods: Deal with diseased branches and leaves promptly and burn them. In addition, do not spray water on the plant after discovering this symptom. If necessary, chemical treatment methods can be adopted, such as spraying with wettable powder of mancozeb, or spraying with agents such as thiophanate-methyl and captan. Pay attention to alternating their use to prevent the virus from producing antibodies to the drugs.

anthrax

Once it is discovered that a plant may be suffering from anthracnose, it is recommended to spray it immediately with mancozeb wettable powder.

Pests of Hamamelis and Their Control

Common insect pests of witch hazel include the great moth and the spiny moth.

Big moth

Once the cysts are found, they should be removed in time and burned in batches. The larvae can be sprayed with dichlorvos to kill them. Adult insects can be killed by light trapping using their phototaxis.

Ligustrum moth

When dealing with caterpillars, you can choose to dig out the cocoons in the soil around the tree base to reduce the source of insects. Then you can also spray with chlorfenapyr emulsion. Pay attention to protection when removing it manually. If you are stung accidentally, you can apply soapy water, edible alkali, etc.