Prevention and control of diseases and insect pests of privet

(1) Disease

The main diseases harmful to privet are rust, brown spot and so on.

Rust the disease mainly harms leaves. Orange spots appeared on the leaf surface in the early stage, and brown spores appeared on the back of the leaf in the later stage. Prevention and control methods: disinfect the cultivation medium in advance, strengthen environmental management, maintain ventilation and light transmission, and remove diseased leaves if necessary; spray Baumei 0.2-0.3 degree stone-sulfur mixture at the initial stage of flowers and trees, or 70% mancozeb wettable powder 500x solution, or 70% methyl topiramate 1000 times solution, or 25% triadimefon 1500 times solution.

The pathogen of brown spot is a kind of fungus, which mainly damages the leaves, and usually begins to occur in the lower leaves, and then gradually spreads to the upper part. At the initial stage of the disease, the lesions were round or nearly round in different sizes, with a few irregular shapes, and the spots were purple-black to black with light edges. Then the color of the lesion deepens, showing black or dark black, which is clearly separated from the healthy part. In the later stage, the central color of the lesion turned pale and was covered with gray-black mildew spots. When the disease is serious, the disease spot is connected into a piece, and the whole leaf turns yellow quickly and falls off ahead of time. Brown spot usually begins to occur in early summer and is seriously harmful in autumn. It is easy to break out in high temperature and rainy years or seasons, especially in years or seasons with frequent storms; the lower leaves are usually more susceptible to infection than the upper leaves. Prevention and control methods: early detection, timely removal of diseased branches and leaves, and centralized burning, so as to reduce the source of pathogens; strengthen cultivation management, shaping and pruning to make plants ventilated and transparent; at the initial stage of the disease, 50% carbendazim wettable powder can be sprayed. 1000 times of Desen zinc wettable powder or 75% chlorothalonil wettable powder.

(2) insect pests

The main pests harmful to privet are female aphids, Spodoptera litura, white wax beetles, longicorn beetles and so on.

Aphids are small and soft insects, which often harm the top tip and tender leaves of the plant and make the plant grow poorly. Control methods: the leaves can be washed with water or soapy water, or the damaged parts can be removed; the source of overwintering insects can be eliminated, nearby weeds can be removed, and the fields can be cleared thoroughly; 1200 times of oxidized dichlorvos solution can be sprayed during the period of aphid danger.

Ligustrum lucidum larvae spin silk to form a net and feed in the net, which can eat all the leaves and affect the growth. Control method: spray 90% trichlorfon 1000-1500 times liquid during the larval occurrence period.

After the ash insect damage, the tree weakens and the branches wither and die. Prevention and cure method: can use dichlorvos EC 1000 times liquid spray.

The larvae of Monochamus alternatus ate the phloem and xylem, and the adults gnawed on the tender bark of new branches. Control method: 50% fenitrothion EC can be sprayed on the wormhole.