Common diseases and insect pests of cherry blossoms

There are many kinds of diseases and insect pests in cherry blossoms. The common diseases and insect pests are as follows:

Perforated brown spot occurs from May to June, the leaves appear purple-brown spots, then gradually expand into a circle, the spot becomes a small hole after drying and shrinkage, the pathogen mostly winters on the diseased branches and leaves, and the optimum temperature for development is 25 ℃ to 28 ℃. When the disease is transmitted by wind, the disease occurs seriously in rainy season, when the tree is weak, poor drainage and poor ventilation.

Control methods: (1) strengthen cultivation management, reasonable pruning, and pay attention to cut off diseased shoots, clean up diseased leaves and burn them in time, so as to create clean growth conditions for plants.

(2) before the germination of new shoots, 3 to 5 Baomedu stone sulfur mixture can be sprayed. During the onset of the disease, 160x Bordeaux solution or 1000 to 2000 times solution of 50% benzoite wettable powder or 15% Dysen zinc solution can be sprayed.

The yellow-green round spots appeared on the summer leaves of leaf blight, then turned brown and scattered with black particles, and the diseased leaves died but did not fall off.

Control methods: (1) remove and burn diseased leaves and spray Bordeaux solution before germination.

(2) spray 65% Dyson zinc wettable powder 500 times from May to June, once every 7 to 10 days, 2 to 3 times in a row.

Root cancer disease mainly occurs at the base of the trunk, sometimes on the root neck or lateral root, the disease part produces a tumor, the initial milky white or flesh color, gradually become brown or dark brown, spherical, rough surface, uneven, cracking, root dysplasia after infection, fine roots are very few, aboveground growth is slow, tree potential is weak, leaves yellowing, early falling, or even the whole plant dies in severe cases.

Prevention and treatment methods: (1) seedlings infected with root cancer must be destroyed centrally. Before planting, it is best to soak them with 1% copper sulfate for 5 to 10 minutes, then wash them with water, and then plant them.

(2) the tumor and its surrounding tissue can be completely removed by knife saw.

(3) the soil around the diseased plant can also be disinfected with sulfur powder according to the dosage of 50 to 100 grams per square meter. At the same time, pay attention to soil improvement.

There are many species of ostracods that damage cherry blossoms, such as Shuimu Jianchu, Bran Shield, Changbai scale, Japanese Turtle Wax and so on. Adults and nymphs suck the sap of branches and leaves to weaken the plant growth, while some species secrete a large amount of excreta, which is easy to induce coal fouling disease and affect its growth and flowering. Prevention and control methods:

(1) the most favorable period for the control of scale insects is the peak hatching period of nymphs, spraying 25% imidophos 600 to 800 times or 40% omethoate emulsion 1000 times.

(2) spray 5 Bomedo stone sulfur mixture or 3% to 5% diesel emulsion in winter and spring to eliminate overwintering nymphs. The effect is better.

The pear net bug mainly harms the back of the leaves of the cherry blossoms, sucking juice, and there are many speckled brown feces and fly-like black left when spawning. The whole damaged leaves are yellowish yellow on the back and pale spots on the front. When the damage is serious, the leaves are flecked, the whole leaves lose green and pale, and the leaves fall early.

Control methods: (1) remove weeds, wither branches and leaves in winter and destroy them centrally. (2) when some newly emerged white adults were found in the nymphs on the leaves, it showed that the first generation of nymphs had basically hatched and should be sprayed and controlled in time. This is a favorable period for control. 1000 times of 90% trichlorfon or 1500 times of 50% malathion EC or 1000 times of omethoate can be used.

The young moth eats the inside of the dry skin of the cherry blossoms, the adult body is blue-black, occurs once a year, and the larvae spend the winter under the skin, so it can be harmful from early spring to Eclosion in August and September, and the eggs are laid in the bark gap or the wound of dry bark.

Control methods: (1) apply lime coating on the branches of cherry blossoms to prevent spawning.

(2) when there is a hole in the dry branch to flow glue or insect dung in spring, you can use a hammer to kill the internal larvae or cut the dry skin with a knife to kill the larvae. And put on a fungicide.

(3) smear the infested area or spray all the branches with a 700-fold solution of 50% phoxim EC to kill the young larvae. During the period of high temperature and drought from June to July, the red spider spiders propagated rapidly and the number increased sharply, which was serious at this time. It mainly pierced the sap of cherry leaves, made the injured leaves lose green and showed gray-yellow spots, caused scorch and early defoliation, yellow and scorched the injured buds, could not spread leaves, affected normal growth and ornamental, and could lead to other diseases and pests.

Prevention and control methods: (1) when individual cherry blossoms are found to have red spiders, they should be removed in time.

(2) before the sprouting of cherry blossoms in early spring, the trunk was sprayed with crystal stone sulfur mixture 300 to 500 times to eliminate overwintering female adults and eggs.

(3) spraying 2500 times of 50% bromoacarate emulsion or omethoate, dicofol and other agents during the damage period.

(4) because mites are easy to produce drug resistance, attention should be paid to the alternate use of acaricides.

Aphids mainly harm the buds of cherry blossoms and new leaves, sucking the juice from the plant with prickle mouthparts, the parts of the killed plants grow slowly, the leaves wrinkle and curl, fall off seriously, and the flower buds can not develop normally, resulting in shedding. The insect can also secrete a large amount of honeydew, induce serious coal fouling disease, and greatly reduce the ornamental nature of the killed cherry blossoms.

Control methods: (1) when the amount of insects is small, it can be washed with clean water or combined with pruning, and the branches of insects can be cut off.

(2) 15% aldicarb granules were applied to the most fibrous roots around cherry trees in mid-late April. 1 to 2 grams of aldicarb per tree was buried in soil depth of 2 centimeters, and the effect was good.

(3) 1000 to 1500 times 50% deltamethrin EC or 4000 to 5000 times 2.5% deltamethrin EC or 2000 times 20% chrysanthemum EC can be sprayed.