Control methods of main harmful mites of cherry blossoms in Sichuan

In Mianyang area of Sichuan Province, the main mites harmful to cherry blossoms are Elm Tetranychus, Hawthorn spider mite and so on. When the young mites, nymph mites and adult mites suck the leaf sap, there are many small green spots in the injured leaves, and the leaves are pale and scorched, which affect not only the plant growth and flowering, but also the photosynthesis.

Morphological characteristics

The female adult of Tetranychus Ulmus is 0.45 mm long, 0.29 mm wide, round, the back is raised, crimson, and the male adult is 0.3 mm long. Summer eggs are orange and winter eggs are crimson.

The female adult of Hawthorn spider mite is 0.49 mm long and 0.32 mm wide, oval and brown, and the male adult mite is 0.33 mm long and 0.18 mm wide. Ovoid, orange-red, orange-yellow or yellowish-white eggs produced later.

Occurrence regularity

Tetranychus Ulmus occurs for about 10 generations a year and overwinters with eggs on branches. In the following year, the overwintering eggs began to hatch from late April to early May, and the adult mites were prevalent in about 2 weeks. The periods from June to July overlapped and propagated rapidly, which was the peak period of damage. Overwintering eggs began to be laid after August and continued until early October.

Hawthorn spider mites occur for about 10 generations a year, with several or dozens of fertilized female adult mites overwintering in hidden places such as bark cracks, litter and topsoil. The stings occurred when the tree buds sprouted in the next year, and the females were full of birth disorder after feeding in the middle of April. the first generation eggs hatched at the beginning of May, and the generations after the second generation overlapped. Overwintering female adult mites appeared in September and all entered the overwintering state in late November.

Prevention and cure method

Before germination, spray 20% acarate wettable powder 800 times, or 5% anthracene oil emulsion, or 5% heavy diesel emulsion to kill overwintering eggs.

When the tree buds sprouted (mid-late March), spurting Baumei 0.5 ml 1 degree stone sulfur mixture, or 4% omethoate EC 1000 times, to control newly hatched young mites and female adult mites.

From the end of May to the beginning of June, the first generation of newly hatched young mites, nymph mites and unspawned female adult mites were controlled with the biological acaricide Liuyangmycin (20% compound) 1000 times, or the 20% acarides wettable powder 800ml 1000 times.

During the period from June to July, spray 73% carbamate EC 4000 times, or 40% paracetamol EC 4000 times, or 20% mifenac wettable powder 2000-3000 times. It is usually sprayed every 10 days and used alternately for 4 consecutive times. When spraying, the middle and lower parts of the plant and the back of the leaves should be fully sprayed and evenly sprayed. Do not spray the same agent continuously to avoid drug resistance.

Weeds and fallen leaves can be removed in winter, and woodland can also be irrigated to eliminate the source of overwintering insects. At the same time, pay attention to the protection and utilization of natural enemies such as mites and ladybugs.