I don’t know if the white color of pines and cypresses is caused by insects or germs. How to deal with it?

It’s a scale insect.

Removal of scale insects in winter:

1. Re-prun diseased branches: In combination with winter pruning, re-prun or thin out the infested branches that have caused serious damage, and dig out the branches that have caused serious damage and are no longer infected. Weak and dead plants with ornamental value are taken out of the garden and burned to reduce the overwintering base and reduce the source of insects the following year.

2. Ice and pest control: According to the local weather forecast, within 1 to 2 days after the cold wave drops, water the trees in the evening to make them freeze, and knock them with a wooden stick the next morning. Hit the trunk and branches, and the scale insects on the tree can be stuck by the ice. Depending on the insect condition on the branches, you can basically remove the scale insects on the tree surface 2 to 3 times throughout the winter. It should be noted that when the tree diameter is less than 5 cm, it is not suitable to use freezing method to remove insects, because small trees have poor stress resistance and are prone to frost damage.

3. Scotch tape and chemicals to remove residue: After the above two-step treatment, there are only a few scale insects left on the tree, which greatly reduces the workload of chemical treatment. For cracks in the trunk and old areas, For a few scale insects under the skin, you can use a wire brush to remove the parts with scale insects before the leaves sprout from March to April of the following year, and then use 50 times diesel additive plus 50% parathion EC 60 times or 10% Apply a mixture of 300 times of cypermethrin emulsifiable concentrate once. After the trunk is air-dried, immediately wrap the coated area with a 5 cm wide transparent tape. Pay attention to sealing when wrapping. After the scale insects resume activity, wait until the branches grow buds. Peel off the tape in a timely manner around the next month, take it out of the garden and burn it. After the above three steps, you can basically remove the scale insects on the tree. This method can also be used to control scale insects on tree root bonsais. It should be noted that the concentration of pesticides should be determined according to the size of the bonsai to avoid phytotoxicity and affect the ornamental value.

4. Rubber ring barrier: The above method can effectively control the occurrence of garden scales. For gardens with heavy paramecium scales, apply a glue ring on the base of the trunk in early spring to kill the nymphs on the tree. , has very good control effect.