Methods and Technical Key Points for Pest and Disease Control in Glossy Privet (Ligustrum lucidum)

(1) Diseases

The main diseases harming glossy privet are rust disease, brown spot disease, etc.

Rust disease: This disease mainly harms the leaves. In the early stage, orange-red spots appear on the leaf surface, and later brown spores appear on the underside of the leaves. Control methods: The growing medium should be disinfected in advance, environmental management should be strengthened, ventilation and light transmission should be maintained, and diseased leaves should be removed when necessary; in the early stage of disease onset in flowering plants, spray with 0.2-0.3 degrees Baume lime sulfur mixture, or 70% mancozeb wettable powder at 500 times dilution, or 70% thiophanate-methyl at 1000 times dilution, or 25% triadimefon at 1500 times dilution.

Brown spot disease: The pathogen is a fungus that mainly attacks the leaves, and typically starts on the lower leaves before gradually spreading upward. In the early stage, the lesions are circular or nearly circular in varying sizes, with a few being irregular; the lesions are purple-black to black, with lighter-colored edges. Subsequently, the lesion color deepens, appearing black or dark black, with a clear boundary from the healthy parts. In the later stage, the center of the lesion fades in color and develops small gray-black mold spots. When the disease is severe, the lesions merge into patches, and the entire leaf rapidly turns yellow and drops prematurely. Brown spot disease generally begins in early summer and causes severe damage in autumn. It easily breaks out in high-temperature and rainy conditions, especially in years or seasons with frequent storms; typically, lower leaves are more susceptible to infection than upper leaves. Control methods: Detect early, promptly remove diseased branches and leaves, and burn them in a centralized manner to reduce the source of pathogens; strengthen cultivation management and pruning to ensure ventilation and light transmission for the plants; in the early stage of disease onset, spray with 50% carbendazim wettable powder at 500 times dilution, or 65% zineb wettable powder at 1000 times dilution, or 75% chlorothalonil wettable powder at 800 times dilution.

(2) Pests

The main pests harming glossy privet are glossy privet aphids, glossy privet geometrid moths, white wax insects, and cloud-patterned longhorn beetles, etc.

Aphids are small, soft-bodied common insects that often harm the shoot tips and tender leaves of plants, causing poor growth. Control methods: Wash the leaves with water or soapy water, or remove the affected parts; eliminate overwintering pest sources, clear nearby weeds, and carry out thorough field cleaning; during the aphid damage period, spray with 40% dichlorvos oxidized at 1200 times dilution.

Glossy privet geometrid larvae spin silk webs and feed within the webs, and can consume all the leaves, affecting growth. Control methods: During the larval occurrence period, spray with 90% trichlorfon at 1000-1500 times dilution.

After damage by white wax insects, the tree vigor weakens and branches die. Control methods: Spray with dichlorvos emulsifiable concentrate at 1000 times dilution.

Cloud-patterned longhorn beetle larvae bore into and feed on the phloem and xylem, and adults also gnaw on the tender bark of new branches. Control methods: Spray with 50% fenitrothion emulsifiable concentrate at 40 times dilution onto the insect holes.