Occurrence and control of main diseases and insect pests of ginkgo tree

Ginkgo biloba, the seed of which is Ginkgo biloba, can be used as medicine, and has the functions of nourishing yin and to

Occurrence and control of main diseases and insect pests of ginkgo tree

Ginkgo biloba, the seed of which is Ginkgo biloba, can be used as medicine, and has the functions of nourishing yin and tonifying kidney, moistening lung, relieving cough, relieving asthma and preventing insects. Common pests and diseases include stem rot, mildew, leaf blight, dry disease, ginkgo moth, peach moth, dead leaf moth, ginkgo leaf curl moth, pod moth, tea thrips and so on.

1. Stem rot: This disease mainly harms L-2-year-old seedlings. High temperature is the main cause of stem rot. Under high temperature, seedlings are damaged, disease resistance is weakened, bacteria grow and multiply rapidly, and invade from the wounds of seedlings, causing diseases. In addition, the low-lying water in the nursery is prone to diseases due to poor seedling growth. In June and August, the weather continued to be hot and the condition was serious.

Sow early, improve the lignification degree of seedlings before the arrival of high temperature season, enhance the resistance to stem rot, disinfect the nursery soil, properly shade and irrigate in time. At the initial stage of the disease, 5O% thiophanate methyl was used for prevention and treatment.

Second, mildew disease: it harms ginkgo seeds during storage, and spreads diseases at a temperature of about 20 degrees Celsius and high humidity. Immature or broken seeds cause more diseases.

Seeds must be harvested after full maturity, while avoiding damaging the seed coat. Dry thoroughly before storage to sort out broken seeds and diseases. Storage room should be kept low temperature and ventilated. Soak seeds in 0.5% potassium permanganate solution for 30 minutes before storage, or spray 10 times solution diluted with 40% formaldehyde for disinfection.

Leaf blight: the pathogen mainly overwinters on fallen leaves, and forms spores to infect new leaves in March of the following year. The seedlings became ill in early June, and the peak period was August-September. Generally speaking, the incidence of seedlings is higher than that of trees.

Strengthen management, remove fallen leaves and apply fertilizer appropriately. Rational distribution of tree species to prevent interplanting with Metasequoia glyptostroboides, pine trees, tea trees and grapes. Young trees and big trees were treated with 500 times solution of 40% carbendazim in early July, and the seedling control time was from early June to late August. At the same time, 0.5% potassium dihydrogen phosphate and 0.2% urea solution were added for spraying to enhance its resistance.

Fourth, dry disease: germs invade tree trunks or branches from wounds, forming irregular spots on smooth bark. It is spread by wind, rain, insects and birds. After May, new disease spots appeared on the trunk, and July-September was the peak of the disease.

Protect the tree body, prevent trauma, strengthen the tree vigor and improve the disease resistance. Remove the seriously ill plants and diseased branches, burn them in time, scrape off the spots on the diseased branches or branches, and smear them with lO% alkaline water. The effect is very good.

Five, ginkgo silkworm moth: it is a large moth, and L generation occurs in L year. Larvae eat leaves. Newly hatched larvae have social habits. L-2 instar larvae can feed from the leaves, but the food intake is very small. After the 4th instar, the damage was dispersed and the food intake increased gradually. After 5 years of age, you can enter the gluttony period and eat all the leaves.

Trap and kill adults with black light in August and September. Remove the leaves damaged by bees before the third instar. In severe cases, spray 2% deltamethrin 2500 times or 90% trichlorfon 1500-2500 times in larval stage.

Peach moth: the L generation occurred in L year. After hatching, the larvae crawl for a certain distance, and then eat into the seed core, eating up all the seed core or leaving only a part. L-headed larvae only eat l seeds.

When the first generation of adults emerged, 80% dichlorvos lOOO solution was used for control. At the peak of egg incubation, 40% clofenuron lOOO solution can be sprayed, and the hatched larvae can be killed for the second time after 7 days.

Seven, Spodoptera exigua: the fruit juice is sucked by adults, and the ginkgo fruit falls off within 3- 10 days after the injury. Eggs are mostly laid on the leaf backs of hosts such as medulla tetrapanacis and Mahonia, and the larvae mature and enter the soil chamber to pupate.

Eliminate host plants such as medulla tetrapanacis and Mahonia around Ginkgo biloba. Spraying 5O% trichlorfon with 5OO times solution from the beginning of May to the middle of June, and then applying/kloc-0 times after lO, the best effect is in the evening.

Eight, tea yellow thrips: both adults and nymphs harm the leaves of seedlings and adults, sucking juice on the back of leaves, and the leaves turn green quickly after sucking, and in severe cases, the leaves turn white and wither, leading to early defoliation. Drought conditions are suitable for thrips, and with the increase of temperature, the damage changes from seedlings to large seedlings and trees.

The drug resistance of thrips is poor, and it is easy to get good results when sprayed in time. During the high incidence period from June to August, 80% dichlorvos lOOO was used to control thrips, and the effect was good by spraying it twice continuously.

Nine, the leaf roller moth of Ginkgo biloba leaves: the larvae drill into the branches and endanger the new shoots of the year, causing dead branches, fallen leaves and fruit drop. The insect has the characteristic of liking light, and it is heavier around the forest edge than in the forest. The degree of occurrence is closely related to temperature. With the increase of altitude and latitude, the annual average temperature decreases and the population density decreases.

Use 2.5% deltamethrin 2500 times solution to control adults before the emergence peak. At the initial stage of larvae hatching, 800 times of 800% dichlorvos EC was sprayed to damage branches.

Ten, stem borers: larvae eat into the seed nucleus and have the habit of turning the fruit into harm. In severe cases, the kernel is eaten up, leaving only insect dung in the kernel, which seriously affects the yield and quality of ginkgo seeds. As larvae burrow into the soil to pupate, its occurrence is closely related to soil moisture and texture, and it is lighter when there is more rainfall and the soil is solid.

No other leguminous plants are planted around, so as to reduce the harm of transfer and reproduction of stem borers. At the peak of adult development, spraying 800 times of 50% dichlorvos or 90% trichlorfon, and carrying out the second control after 10 days, the effect is good.