Control techniques of diseases and insect pests of Lycium barbarum

The prevention and control of diseases and insect pests of Chinese wolfberry is one of the main contents of the management of Chinese wolfberry orchard. In the management of Chinese wolfberry growing season, pest control accounts for 1/3 of the workload. Although the yield and quality of Chinese wolfberry are closely related to varieties and fertilizers, in order to achieve the goal of safety, high quality and high yield, the production of green Chinese wolfberry products has an advantage in domestic and foreign markets. the key depends on the level of pest control. The main pest control methods are as follows:

(1) anthracnose of Chinese wolfberry

Symptoms of Chinese wolfberry anthracnose disease commonly known as black fruit disease, mainly harmful to green fruits, twigs, leaves, buds, flowers and so on. At the beginning of the green fruit infection, there are small black spots or irregular brown spots on the fruit surface, and the disease spots continue to expand in case of continuous rain, half or the whole fruit blackens, and the fruit overflows when dry; when the humidity is high, many orange colloidal spots grow on the diseased fruit; twigs, leaf tips and leaf edges are infected with brown semicircular spots, which become black after expansion, wet rot with high humidity, and sticky orange spots appear on the surface of the diseased part, that is, conidia and conidia of pathogens.

Pathogen Glomerella cingulata (Stonem.) Spauld. Et Schrenk calls it a small clump shell, which belongs to ascomycetes. The anamorph is Colletotrichum gloeosporioides (Penz.) Sacc. It is called Colletotrichum gloeosporioides, which belongs to half-known fungi. The conidium grows under the epidermis of the diseased fruit, and the mycelium gathers in the intercellular space of the subcutaneous tissue, forming a dark-brown conidium disk, disk-shaped, protruding in the middle, 100 ~ 300 μ m in size, few bristles, pericarp and cuticular layer at the top of the epidiospore disc, and conidium clavate in size 12 ~ 21 × 4 ~ 5 (μ m). Conidium cylindrical, size 11 ~ 18 × 4 ~ 6 (μ m). The suitable relative humidity for conidia germination is 100%. When the humidity is below 75%, it does not germinate, and a large number of conidia germinate after 24 hours in water.

The route of transmission and disease conditions overwintered with mycelium and conidia on Lycium barbarum trees and ground diseased residual fruits. In the spring of the following year, Rain Water spattered the conidia bonded together and spread them to young fruits, flowers and buds. Through the wound or direct invasion, the incubation period was 4-6 days. In rainy years, the disease expanded rapidly in rainy years, showing a heavy rain peak and a light rain peak. The water film on the fruit surface is conducive to spore germination. When there is no rain, the spores germinate when there is water film or dew drops on the fruit surface at night. In dry years or dry and non-rainy seasons, the disease is mild and spreads slowly. The disease began from mid-May to early June and broke out from mid-July to mid-August. when the damage was serious, the rate of diseased fruit was as high as 80%.

Control methods (1) cut off diseased branches and fruits in time after harvest, remove diseased and residual fruits from trees and on the ground, and concentrate on burying or burning them. The disease and residual fruit on the tree and the ground were removed again before the first rainfall in June, and the source of primary infection was reduced. (2) spraying once before the first rainfall in June, and adding appropriate amount of urea to the solution to kill the overwintering pathogen and enhance the disease resistance of the tree. (3) emphasis should be placed on spraying after rain, and the spraying time should be carried out within 24 hours after rain to prevent conidia germination and invasion after transmission. (4) during the disease period, flood irrigation is prohibited, stagnant water in Qi garden is excluded after rain, and watering should be carried out in the morning to control field humidity and reduce fruit surface dew at night. (5) timely control of aphids and mites during the onset of the disease to prevent pests from carrying spores to transmit disease and cause wounds. (6) in the early stage of the disease, 25% trimethoprim wettable powder, 80% anthrax Fumei wettable powder, 25% Baogong EC, 50% Baogong or 1000 times of Baike wettable powder, 75% chlorothalonil wettable powder 1000 times, 70% mancozeb wettable powder 1000 times, 50% carbendazim (carbendazim) wettable powder were sprayed. Once every 10 days or so, continuous prevention and treatment for 2 or 3 times. In addition, it has been reported that spraying kenaf anthracnose or citrus leaf anthracnose at the initial stage of the disease has a control effect similar to that of 80% anthrax Fumi wettable powder 800 times and has no pollution, so it belongs to biological control method. It can be tried out in production.

(2) powdery mildew of Chinese wolfberry

The main symptoms are damage to leaves. There are nearly round white powdery mildew spots on both sides of the leaves, and then expand to the whole leaf covered with white powder to form white patches.

Pathogen Arthrocladiella mougeotii (L é v.) Vassilk. Var. Polysporae Z. Y. Zhao. It is called polysporium, belonging to ascomycetes. The ascus is scattered or slightly aggregated, brown to dark brown, 120 ~ 165 μ m in diameter; there are 81 attached filaments, the base is rough, yellowish brown, short rod-shaped or finger-shaped, some with septum, 0.6 × 1 times the length of the ascomycete, with 11 × 31 ascyst; the ascus is oval to long oval, stipitate, with a size of 59 ~ 74 × 14 ~ 21 (μ m), containing 2 × 4 ascospores. Ascospores are oval to long oval, with a size of 13.8 ~ 21.3 × 12 ~ 15 (μ m).

Transmission route and disease condition: the northern pathogen overwintered with closed cysts on the soil surface with the disease remains, and the ascospores were emitted for primary infection in the following spring. Southern pathogens sometimes produce closed cysts or overwintering on the host with mycelium. After the disease occurred in the field, the conidia produced in the disease department were transmitted by airflow and re-infected. When the conditions are suitable, the spore germination produces infection filaments to invade directly from the epidermal cells, and produces haustorium in the epidermal cells to absorb nutrients, and the mycelium creeps on the host surface with attachments and spreads continuously, forming a closed capsule at the end of autumn or continuing to winter as mycelium on the living host.

Prevention and treatment methods (1) removal of diseased bodies and fallen leaves in early autumn and early winter, concentrated deep burial or burning. (2) pay attention to ventilation and light in the field, do not plant too dense, and remove overdense branches if necessary. (3) at the initial stage of the disease, 36% thiophanate suspension or 50% carbendazim (carbendazim) wettable powder 1000 times, 60% Fangmaibao No. 2 water-soluble powder 1000 times, 20% triadimefon EC 1500 times, 30% basic copper sulfate (Ludabao) suspension 400x, 45% crystal stone sulfur mixture 150x, once every 10 days, continuous prevention and treatment for 3 times. Areas that are resistant to the above-mentioned fungicides can use 40% Fuxing EC 7000-8000 times, once every 20 days, once or twice. Stop using medicine 3 days before harvest.

(3) Root rot

Symptoms: harm to the rhizome, at the beginning of the disease, the whisker root turned brown and rotten, then spread to the main root black and rotten, and in severe cases, the outer skin rotted and peeled off, leaving only xylem, and finally the whole plant withered. The root rot of Lycium barbarum mainly harms the root and stem base of the plant. The appearance of the diseased plant showed yellowing and drooping leaves. Digging up the diseased plant to examine the root and stem showed that the affected part turned brown to dark brown, and some of the cortex rotted and fell off, exposing xylem. The vascular bundles inside the rhizome also turned brown. Sometimes white to pink powdery mildew symptoms appear on the surface of the affected area (conidiophores of pathogens).