Lavender pests and diseases

Diseases

Lavender leaf spot

Symptoms for one-year-old sown seedlings and cuttings are wilting, water loss, dull color, bent branches, and in severe cases, root withering and rot, and the stem ducts turning brown. In addition to the above symptoms, seedlings over three years old also show wilting symptoms that spread from the center or edge of the plant to the outside, and the branches wilt and die until the entire plant dies.

The main prevention and control method is to spray Bordeaux mixture 1:200 2 to 3 times, or 500 to 800 times diluted Mancozeb.

Lavender root rot

Because the lavender seedlings do not respring or respring poorly, they dry up and die, or they can respring normally in spring, but the bouquets wilt in the early stage of flowering, and the flowers continue to fall until all fall off. Autopsy of the diseased plants reveals that a large number of vascular bundles in the rhizomes are necrotic.

There are many ways to prevent this disease, the main ones are to choose flat terrain with good drainage and irrigation conditions for planting; collect disease-free field seedlings and branches when planting seedlings, and treat them with thiophanate-methyl or carbendazim; apply organic fertilizer; pay attention to pruning old and diseased branches; make preparations before wintering and bury the soil tightly and evenly; the most important prevention and control method is to spray leaves with 400 times diluted 70% thiophanate-methyl wettable powder or 500 times diluted 50% carbendazim wettable powder.

Pests

Red Spider

Lavender spider mites are a type of mite that eats away at the leaves, causing them to wither, dry out, and turn yellow with rust.

The prevention and control methods mainly include timely disposal of dead branches and leaves, cleaning the environment to destroy the living habitat of spider mites; correct farming methods, reasonable crop rotation, and strengthened water and fertilizer management; protecting natural enemies, releasing natural enemies, and using insects to control insects. There are also other prevention and control methods: in the early stage of the disease, evenly spray 1000 times of 0.26% matrine solution. When it occurs in a large area, evenly spray 1000~2000 times of 20% trichlorodicofol emulsifiable concentrate, or 3000~4000 times of 1.8% avermectin emulsifiable concentrate, which has a better prevention and control effect.

Leafhoppers, flea beetles

The main prevention and control method is to use pyrethroids such as 50% cypermethrin emulsifiable concentrate, 50% carbofuran emulsifiable concentrate, and 12% cypermethrin emulsifiable concentrate.