Harmful symptoms of rose rust and its control techniques

Recently, the flower growers who have planted the rose have a more distressing problem, that is, what if the rose gets rust? Is there any cure? Rose rust is actually a frequent and frequent growing leaf disease, which harms buds, leaves, twigs, petioles, receptacles, pedicels and other parts of rose, mainly on buds and leaves. Next, let's learn the prevention and control measures of next month's seasonal rust with the editor.

I. harmful symptoms

During the sprouting period in spring, the initial stage of the diseased bud was light yellow, the base was swollen, and a large number of orange powdery substances grew in 1 ~ 3 layers of scales, like small yellow flowers. The diseased buds could not grow, some were bent and deformed, and withered after 15-20 days. After the young leaves were damaged, the yellow punctate spore organs were clustered on the front of the leaves, showing irregular yellow disease spots. After that, a pile of orange summer spores was formed on the back of the leaf, and in severe cases, the leaf surface was covered with spots.

A black-brown powdery pile of winter spores was produced on the disease spot on the back of the leaves in autumn, and the axillary buds died after overwintering after being infected by pathogens in autumn. The damaged parts of the plants often bulge or overgrow or show abnormal shape, and the leaves of the infected plants fall early and the growth is weak.

Second, the law of the disease.

Rose rust pathogen overwintered mainly by mycelium in diseased buds or diseased sites, or by winter spores on withered branches and fallen leaves. The disease occurs in the leaves in late April every year. The peak period is from late May to early July and from late August to late September. In the first ten days of August, the average temperature was above 27 ℃, the disease did not develop, and when the temperature was above 28 ℃, the summer spores did not germinate. After late September, only axillary buds occurred. Temperature plays a key role in the epidemic of the disease, and water is also important for the germination of rust spores and summer spores. Generally, spores can germinate only in the presence of free water. Therefore, it is beneficial to the occurrence and epidemic of the disease in the years with more and uniform Rain Water and the rainy and foggy areas where the four seasons are warm, while it is lighter in the areas with high temperature in summer or cold in winter.

III. Prevention and control techniques

The application of resistant varieties selection of rust-resistant rose varieties and disease-free mother plants is one of the important measures to control rose rust, which plays an important role in the control of rose diseases.

1. Horticultural measures

In rose production, avoid continuous cropping and crop rotation to avoid the spread of germs with the flow of water. When potted, the soil should be changed in time. Choose high dry and fertile sandy loam to avoid close planting and keep the plant ventilated and transparent. Rational fertilization, rational use of nitrogen fertilizer, the use of fully mature fertilizer to promote the healthy growth of plants. Remove the disabled body in time, reduce the source of infection, collect the disabled body, and destroy it centrally. During the examination from late March to early April, the diseased buds should be removed and destroyed immediately. Generally, the rate of diseased buds is less than 0.5%, and spores can be prevented from spreading after removal.

two。 Chemical control

After pruning in early spring, spraying 2-5 Baume-sulfur mixture and spraying 1-2 times before the peak of the disease in early April or late August can control the development of the disease. During the onset period, spraying 50% mancozeb 500x solution, 25% fenuoning wettable powder 1500 times liquid or 0.2% 0.4 Baomeidu stone sulfur mixture, spraying every 10 to 15 days, continuously spraying 2 times, or using 20% verapamil EC 800 times, spraying once every 30 days, can play a better prevention and control effect.

The above is about the incidence of rose rust and its prevention and control methods of all the content, if your home breeding rose also occurred this harm, then hurry to Huinong network to learn how to prevent it!

Symptoms and control of rose rust (scientific name: Rosa chinensis Jacq.): known as the queen of flowers, also known as "moon red", is an evergreen, semi-evergreen low shrub, the four seasons bloom, generally red, or pink, occasionally white and yellow, can be used as an ornamental plant, can also be used as a medicinal plant, also known as rose. There are three natural varieties, modern rose flowers are diverse, single and double, and beautiful flower patterns such as high-heart crimping; its colors are bright and rich, not only red, pink, white and other monochrome, but also mixed color, silver edge and other varieties; most varieties have fragrance. There are many varieties of rose, there are nearly ten thousand in the world, and there are more than a thousand in China.

Rose rust is harmful to leaves, twigs, flowers and fruits. The symptoms on leaves and buds are the most obvious. In the early stage of the disease, a small yellow bulge appeared on the back of the leaf, which gradually expanded and broke through the lower epidermis to spread orange powder, that is, a pile of rust spores. The diameter is 0.5-1.5 mm, and there are often faded rings in the periphery of the lesion. On the front of the leaf, there are orange-yellow blister spots, that is, diseased spore organs. With the development of the disease, the back of the leaf has a slightly larger polygonal spot, about 3-5 mm, accompanied by a rust-colored powder, that is, a pile of pathogen summer spores. After the end of autumn, the brown-black powdery substance is produced on the back of the leaves, that is, the germ teliospore pile. The twigs and fruits are infected, and the disease spots are obviously protruding, round or long oval. Rose rust is caused by rose polyspore rust of subphylum basidiomycetes, Dipterospora, Puccinia, Puccinidae and Puccinia. The pathogen produces five types of spores, namely, sexual spores, rust spores, summer spores and teliospores, while teliospores germinate to produce basidiospores, all of which have different morphology, function and infection transmission ability. Rose rust overwinters with hyphae or teliospores on diseased buds and diseased branches and leaves. In the following year, winter spores germinate basidiospores, invade plant productive spores and rust spores, rust spores re-infect to produce summer spores, summer spores invade through stomata, spread by wind and rain, and spread repeatedly in the growing season. The optimum temperature for the growth and development of teliospores, rust spores and summer spores is 18 degrees Celsius, 10-21 degrees Celsius and 19-27 degrees Celsius respectively. Generally speaking, there is more autumn rain and high rate of diseased buds in spring; if there is more spring rain, the rate of diseased leaves is high. The temperature is high in summer or low in winter. If the cold time is long, the disease is generally not serious, if the four seasons are warm, rainy, dewy and foggy, the summer spores can grow and infect all the year round, and the disease will occur seriously. Among the varieties, double red rose and Gansu lobular rose were the most susceptible, while Beijing single red rose, white rose and Soviet perfume rose were more resistant. Prevention and control methods 1, combined with cleaning and pruning, remove diseased branches, diseased leaves and diseased buds, sweep the fallen leaves in the field, and burn them centrally. 2. Proper application of calcium, potassium, phosphorus and magnesium fertilizer to improve plant disease resistance. 3. Spray 1500 times of 25% verapamil or 50% dinitrate dispersible wettable powder or 3000 times of 75% oxidizing rustling emulsion during the attack. Symptoms and control methods of rose rust

Rose rust occurs in countries with suitable climate all over the world. It sometimes causes serious harm to rose cultivated in greenhouse. In addition to rose, the disease can also infect roses, roses and other flowers.

Pathogen

There are many kinds of pathogens of rose rust, including 10 species reported abroad and 3 species known in China. Among them, Phragmidium montivagum (Pers.) Schlecht. Is the main pathogen, which belongs to the subphylum of fungal basidiomycetes and polyspore rust.

Symptom

The disease is mainly harmful to leaves, petioles and buds, as well as shoots, calyx and fruits. In spring, a small orange blister appeared on the front of the damaged leaf, which was the sexual spore organ of the pathogen; later, a slightly raised orange spot appeared on the back of the leaf, that is, the rust spore apparatus, which broke through the epidermis and scattered orange rust spores after maturation. There is often a faded ring around the disease spot. Soon, orange summer spore powder piles were produced on the back of the diseased leaves. In the late growing season, a brown to black small powder pile of teliospore was formed in the part where the summer spore pile was formed. The damaged parts of the plants often bulge or overgrow or show abnormal shape, and the leaves of the susceptible plants fall early and grow and decline.

Morbidity regularity

The pathogen overwinters on diseased buds or diseased sites, or overwinters with winter spores on withered branches, diseased leaves and fallen leaves. The pathogen is a single host parasitic rust, that is, five stages in the life cycle occur on the same host. In the following spring, teliospores germinate and produce basidiospores, and basidiospores germinate and invade new leaves to form primary infection. In the growing season, summer spores spread by wind and rain, invade by stomata, and can be re-infected many times.

Popular characteristics

Temperature plays a key role in the epidemic of the disease. The most suitable temperature for teliospore germination was about 18 ℃, but it was difficult to form spores at 25 ℃. The optimum temperature for rust spore germination was 15-21 ℃. Although most of the summer spores could germinate at 9-25 ℃, the optimum temperature for germination was 18-21 ℃. Water is also very important for the germination of rust spores and summer spores. Generally, spores can germinate only when there is free water. Therefore, the rainy and foggy areas with warm seasons are beneficial to the occurrence and epidemic of the disease, while the occurrence is lighter in areas with high temperature in summer or cold in winter.

Prevention and cure method

① reduces the source of infection: combined with pruning, collection of diseased remains, and centralized destruction.

② does not plant diseased seedlings and uses nitrogen fertilizer rationally.

③ chemical control: after pruning in early spring, spray Baume 2-5 degree stone sulfur mixture. Spray 50% mancozeb 500 times solution, or 97% rust sodium 250-300 times solution, or Baume 0.2-0.4 degree stone sulfur mixture, or 50% dinitrate powder 200 times liquid, spray once in 10-15 days, spray 2-3 times. Or 20% verapamil EC 800 times, spray once every 30 days.