Key points of prevention and control of rust of Tripterygium

Prevention and control methods: 3, Begonia early spray.

The maintenance points of the bonsai with stem crabapple (1) Maintenance management place: The bonsai with stem crabapple should be placed in a place with sufficient light and air circulation. Summer high temperature, to appropriate shade, to prevent sunburn leaves charred. Winter can be cold, can be buried in the soil basin, can also be put into the indoor window. Watering: usually keep the basin soil moist, but pay attention to prevent ponding in the basin, otherwise it is easy to rot roots. Spring and summer growing season pot soil should not be too dry, especially during flowering to maintain sufficient water pot soil. Fertilization: winter should apply enough base fertilizer, dry cake fertilizer or decomposed manure and bone meal is the best. During the growth period, except for the rainy season, thin fertilizer is often applied. Pruning: mostly after flowering, generally cut short the flowering branches to promote the formation of branches and flower buds and increase the number of flowers in the coming year. At the same time, the long branches, cross branches, overlapping branches and other effects of beautiful branches should also be cut off in time. After defoliation, the dormant period can be pruned, and the withered and senescent branches can be pruned to maintain a certain tree shape. Turning pots: It is advisable to carry out once every 2 to 3 years, preferably after flowering in spring, or in autumn. When turning pots, combine pruning roots and put base fertilizer at the bottom of pots. Disease and pest control: Begonia stem often rust damage leaves, can spray Baume 0.5 degrees of sulfur mixture for control. Insect pests are mainly aphids, thorn moths, red spiders and so on. Control methods with the Malus. (2) Watch the early spring flowering of Begonia, red and beautiful colors, is the best viewing period. Autumn bear yellow pear fruit, smell fragrant, but also quite ornamental value. If the stem attached crabapple is put into greenhouse culture after autumn, it can bloom ahead of time in Spring Festival. Occurrence and control of flower rust

Rust: caused by fungi of the order Puccinia of the subphylum Basidiomycetes. It mainly harms the leaves of horticultural plants, causing leaf blight and early leaf fall, seriously affecting the growth of plants. It is named because of the large amount of rust produced in the diseased part.

(i) Rose rust

Symptoms: The aboveground parts of roses can be damaged, mainly harming leaves and buds. Spring buds are covered with bright yellow powder; the front of the leaves have chlorotic yellow spots, and the back of the leaves have yellow powder piles, which later become black powder piles. The diseased leaves withered and fell early.

The disease can infect the bud, leaf, receptacle, tender branch and other parts of rose. In spring, the infected bud is pale yellow, the bud is swollen, and the diseased bud dies one after another. After the axillary buds are infected in autumn, a few of them can grow leaves and die after winter. The infected leaves showed pale yellow irregular spots on the front and black spores on the back, and the leaves dropped off early.

2. Pathogens: There are many kinds of pathogens of rose rust, 9 kinds are known abroad, and 3 kinds are known in China (fungi). Phragmidium mucronatum (Pers.) Schlecht] and Phragmidium rose-rugosae Kasai. Phragmidium rose-rugosae.

3, the incidence of law

(1) The pathogen overwinters in bud as hyphae, which is the main infection source in the coming year.

(2) The fungus is a mono-host parasite. Bulgarian red rose, white rose and former Soviet perfume rose were more resistant to the disease.

(3) The suitable temperature for disease onset is 24-26 ℃, and rainfall is the dominant factor for disease epidemic.

(4) The pathogen overwinters in bud or diseased site. The disease started in late April and became serious from June to August. The disease is lighter in summer with high temperature and cold winter, and more serious in warm, rainy or foggy weather.

4. Prevention and control methods

(1) Discovered disease buds are removed and destroyed in time.

(2) Spray 25% triadimefon wettable powder 1500 times solution, or spray 75% chlorothalonil 800 times solution, or spray 250-300 times solution of sodium rust.

(3) Strengthen management, reduce humidity, pay attention to ventilation and light transmission or increase potassium fertilizer and magnesium fertilizer to improve the disease resistance of plants.

(4) Remove and burn dead branches and leaves in time to reduce pollution sources. 2, generally in late June and mid-August before the peak period of spraying, spraying once every 8-10 days, 2-3 times in a row. The medicament has 75% chlorothalonil 800 times liquid and 50% tuizhongte 500 times liquid.

(2) Pedicel crab rust

1. Symptoms: Yellow-green spots appear on the leaves at first, gradually expanding into orange-yellow or orange-red shiny circular spots, 6-7mm in diameter, with yellow-green halo rings on the edges, on which orange-yellow small spots appear, and then turn black. The diseased tissue is thickened and slightly bulges toward the back of the leaf, on which many yellow-white hairs grow. Finally, the diseased spot dies and damages the leaves and green branches of the host cypress.

2. Pathogens: Gymnosporangium haraeanum, G.yamadai.

(1) In China, pear gum rust is dominant, and Yamada gum rust is found only in a few provinces. Both of them are host parasites.

(2) Malus acuminata was damaged at the stage of sex spore and aeciospore, but it lacked the stage of summer spore. The stage of teliospore occurred on the alternate hosts of Sabina chinensis, Sabina chinensis, Sabina chinensis and Sabina chinensis. The two rust species were very similar in morphology.

(3) The sexual sporangium occurs under the epidermis of leaf surface, nearly round or flat flask shape, breaks through the epidermis when mature, the orifice is exposed, and many inseminating filaments extend out. Rust seed organ born on the back of leaf spot or petiole spot, thin cylindrical. The pathogen overwinters in hypha in diseased tissues such as Sabina chinensis.

3. Prevention and control methods

(1) Avoid planting Sabina chinensis and other alternate hosts around the planting area of Begonia sp.;

(2) Before teliospores germinated in early spring, 350-fold solution of pyridoxine or sodium pentachlorophenol was sprayed on Sabina plants to inhibit teliospores germination;

(3) After spreading leaves, spraying 1 000-1 500 times of 25% triadimefon or 1 000 times of 50% carbendazim or 200 times of bordeaux mixture had better control effect.

(iii) Carnation rust

1. Symptoms: harm leaves and stems. The infected leaves and stems had reddish brown blister spots, 1.5-8mm long. The epidermis of the infected parts ruptured to form cinnamon urediospores, causing the leaves and plants to wither and die, and forming dark brown teliospores in the later stage.

2. Pathogen: Uromyces dianthi is a host parasite, overwintering with teliospores, germinating in the next spring and infecting Euphorbia plants, producing sexual spores and aeciospores, which infect Dianthus again. In addition to harm carnation, this disease also harm Chinese carnation and American carnation.

3. Prevention and control methods

(1) Remove the diseased leaves in time and thoroughly remove the diseased bodies after autumn to eliminate or reduce the initial infection sources of the following year.

(2) Keep good ventilation and control humidity in the greenhouse.

(3) Spraying mancozeb, captan and other protective chemicals at the early stage of disease or using 400 times solution of 20% chlorpromazine EC.

(iv) Peony rust

1. Symptoms: After peony leaves are infected, there are no obvious disease spots on the leaves, or there are round and irregular brown spots on the leaves, and the yellow spots on the leaves are broken to expose yellow powder piles, i.e. summer spore piles. At the later stage, clusters or scattered dark brown and slender hairs appeared on the back of leaves, namely teliospores, which infected branches and caused spindle tumors on the host pine trees.

2. Pathogenic fungi (1) Cronartium flaccidum is the main parasite.

(2) The rust overwinters on pine trees as hypha, and produces sexual spores and aeciospores on pine trees from April to June. After the aeciospores mature, they spread to peony trees by air flow to infect them and produce urediospores. During the growth period, urediospores repeatedly infected pine trees, and teliospores were formed in the later stage.

(3) It usually occurs after the flowering period of peony and peony. 7-8 The month is dangerous. Warm and humid, much wind and rain conducive to the occurrence of low-lying, poor drainage garden easy to disease.

3. Prevention and control measures

(1) Strengthen cultivation management, plant in higher terrain, good drainage area.

(2) The diseased plants and diseased bodies of herbaceous hosts were not cleared in autumn.

(3) 800 times solution of 15% triadimefon was sprayed during disease onset.

(v) Gladiolus rust

1. Symptoms: Orange blotches (urediospores) appear on both sides of the leaves, and small black teliospores can be produced around the urediospores in 3~6 weeks.

2. Pathogenic bacteria: Uromyces transuresalis (Thuem.) Wint

3. Pathogenesis rule: When the disease is at 16~280C and the relative humidity is 80%~100%, the disease is epidemic due to the transmission of urediospores by airflow. No resistant varieties have been found.

4, control points: can spray benzolite, mancozeb and other chemicals.

(vi) chrysanthemum rust

1. Symptoms: The following three kinds of rust can occur on chrysanthemum.

Black rust: mostly brown blisters formed on the back of the leaf (pycnospore pile). After cracking, yellow-brown urediospores are released, and black-brown teliospores are produced in the later stage.

White rust: produces pale white to pale brown pimples on leaf backs. The whole leaves of seriously ill plants are covered with rust spots, resulting in early wither of leaves.

Brown rust: summer spore pile is born on leaf adaxial surface, orange yellow. Long-term stay under the epidermis, after opening holes.

2. Pathogen black rust: Puccinia chrysanthemi Roze white rust: Puccinia horiana P Henn brown rust: Phakopsora artemisiae Hirat

3. Pathogenesis rule: black rust pathogen overwinters on diseased plants as tetraspore mass and hyphae. The infection occurred between 16 ℃ and 27 ℃, and the disease was more common in cold areas. White rust overwinters in buds and infects new seedlings in spring. Warm and rainy weather favors the onset of illness. There are differences in disease resistance among chrysanthemum varieties.

4. Control methods (1) Select disease-free plants as propagation materials. (2) The planting land requires high and dry terrain, good drainage, fertile soil, ventilation and light transmission. Plant density appropriate, not excessive nitrogen fertilizer. (3) Discovered diseased leaves, immediately removed and burned; after flowering. Remove diseased plants. (4) During the disease. Bordeaux mixture can be sprayed, triadimefon, rust spirit and other chemicals. Spraying once every 10-15 days; zineb, chlorothalonil and other pesticides also have good control effect.