What disease is the bud and leaf of Chinese rose blackening?

Diseases: rose powdery mildew, rose green leaf disease, rose black spot disease.

Pest: Tetranychus schrenckii, a green blind stinkbug mite.

Rose powdery mildew

Symptoms: powdery mildew of rose is a worldwide disease, which harms rose, rose, rose and other plants. Pathogens infect leaves, floral organs and shoots of Chinese rose. In early spring, the leaves with diseased buds are covered with white powder on both sides. The leaves shrink, roll back, thicken, dry up and die gradually, and become the primary source of infection. In the growing season, when the leaves are infected, small white speckles first appear, which gradually expand into round or irregular white speckles. In severe cases, the white speckles are connected with each other. When shoots and petioles appear, the lesion is slightly enlarged and the internodes are shortened. Hualei was covered with white powder, shrinking and drying up. Mild buds produce deformed flowers.

In a word, powdery mildew is harmful to rose, causing early defoliation, dead branches, abnormal buds or failure to open, which seriously weakens the growth of rose when it occurs year after year. The pathogen of this disease is rose mononucleosis. Roses are only asexual, that is, powdery mildew fungi. Combined with pruning, diseased branches, diseased buds and diseased leaves are removed to destroy and reduce invasion. The methods of chemical control of rose powdery mildew are as follows.

(1) Spraying Pomei 2~3 degree stone sulfur mixture during dormancy to eliminate the overwintering hyphae in the diseased bud or the closed capsule shell of the diseased part.

(2) There are 65,438+0,500 ~ 2,000 times of 25% triadimefon wettable powder, 65,438+0,500 ~ 2,000 times of 50% benomyl wettable powder or 250 times of sodium bicarbonate commonly used in chemical control. Sulfur powder is often used for cold protection in greenhouses.

(3) Bio-pesticides such as B0-10 and antifungal agent 120 also have good control effects on powdery mildew.

The chemical name of antifungal drug 120 (Nong Kang 120, TF- 120) is called pyrimidine nucleoside antibiotics. It is a new variety of Streptomyces, which is white powder in appearance, soluble in water, insoluble in organic solvents, stable in acidic and neutral media, and unstable in alkaline media. Antibacterial 120 is a broad-spectrum antibiotic, which has a strong inhibitory effect on many plant pathogens. The control of rose powdery mildew is to spray the effective concentration of 100 mg/L every 15~20 days, and spray it continuously for 3 times.

Rose green leaf disease

Symptoms: Petals are thin and narrow, showing green sepals or leaves, corollas turn green and flowers turn leaves, which is a typical symptom of rose green petal disease. Under the same cultivation and management conditions, the plants suffering from this disease have shorter plant types, more lateral branches, narrower leaf shapes and less red petioles and stems. Flowers are prolific and flowery. Until winter, green flowers last for a long time, but in summer when the temperature is high, the base of the flower stalk is easy to delaminate and will fall off when touched.

Pathogen: Mycoplasma-like organism, which exists in phloem cells at the base of leaflike corolla and tender petiole of "green calyx", is oval and nodular, and new individuals formed after division are mostly spheroids, with individual diameter of 100-800 nm.

Transmission route: Recently, it is known that the main route of virus transmission is artificial grafting transmission, and whether there is still insect transmission in nature remains to be investigated.

Prevention and cure method

1, strengthen quarantine to prevent virus-free vaccines from being brought into disease-free areas.

2, timely prevention and control of tobacco pests and other suspicious media.

3. Use disease-free plants as propagation materials, remove diseased plants in time, and reduce the spread of bacteria.

Black spot of rose

Rose black spot, also known as brown spot, is a worldwide rose disease.

Symptoms: the leaves, branches and pedicels of Chinese rose will be hurt. The diseased spots on the leaves are purple-brown to brown spots at first, and then expand into circular spots with a diameter of 1.5~ 13 mm, black or dark brown, with cilia on the edges, but the upper edges of individual varieties can be neat and smooth. There are often yellow halo around the lesion. Under the magnifying microscope, small black blisters can be seen at the lesion, and the lesions are often connected together, and the leaves around the lesion turn yellow in a large area, making the lesion an "island" with green edges. Sick leaves fall off easily, but some rose varieties don't. Purple to black striped spots are produced on young branches and pedicels, and these spots are slightly concave. When the disease occurs seriously, all the lower and middle parts of the whole plant fall off, leaving only a few new leaves at the top.

Pathogen: Actinomyces rosea. )fr。 Acervulus, an actinomycete, was born under the epidermis of the host and then extended out of the epidermis. The size is 108~ 198 micron, and the conidiophore is short and inconspicuous. Conidia are oval or swim bladder-shaped, with the size of 18~25*5~6 microns, bicellular, small on the top and large on the bottom, with a few bundles at the separation. The tip is beak-shaped, usually leaning to one side.

Transmission route: hyphae overwinter on diseased branches, diseased leaves or diseased leaves, and form umbilicus in early spring of the following year, which leads to the spread of conidia. Conidia is also one of the primary infection sources. Conidia spread harm through wind and rain and splashing water droplets, and it is easy to get sick if it is rainy and foggy and exposed for more than 2 days. According to the experiment, spores can germinate and invade within 6 hours when there is water on the leaves. The suitable temperature for germination and invasion is 20 ~ 25℃, the pH value is 7 ~ 8, and the incubation period is10 ~1day. The incubation period of old leaves is slightly longer, which is 13 days. This pathogen can be repeatedly infected and will get sick throughout the growing season. Generally, it is serious in rainy season and typhoon season, and it spreads slowly in hot summer and dry season. Plants tend to get sick when they are weak. There are differences in disease resistance among varieties, but there are no immune varieties.

Prevention and cure method

1. Clean up fallen leaves and pick diseased leaves at any time to reduce the source of infection. In winter, prune seriously ill plants to remove overwintering pathogens from diseased stems.

2. Don't place potted plants too densely, and it's best not to put them directly on the ground, so as not to get too wet when the ground accumulates water. It is best to put them on a stepped planting platform. Improve the watering method and time, and water from the edge of the basin to avoid spraying. Don't water at night, lest the leaves will dry quickly with water, which is conducive to the invasion of germs.

3. Chemical control. Spraying should be started in summer when the new Ye Gang is launched, usually 7 ~ 10 times a day. The chemicals used are 500- 1000 times of 50% carbendazim wettable powder, 500 times of 75% chlorothalonil wettable powder, 500 times of 80% zineb wettable powder,1:100 times of bordeaux wettable powder, or 70% thiophanate methyl. After pruning in winter, you can also spray 3 ~ 5 degrees of lime-sulfur mixture to eradicate germs.

giant salamander

Giant salamander moth is an omnivorous pest, which harms ornamental plants such as plum blossom, wintersweet, rose, rose, camellia, osmanthus fragrans, pomegranate, cherry blossom, crape myrtle, peach blossom and iris. Larvae eat leaves with holes or nicks. In severe cases, they eat all the leaves on the plant, leaving only the veins.

When the newly hatched larvae are on the host plant, the plant tissue fragments are first bitten and connected with silk to form a protective envelope, which can be formed after 3-4 hours. The females are all in the pouch. After the protective capsule is formed, the larvae begin to eat. When larvae eat and move, their heads and chests stick out of the sac and carry it. When the worm grows up, the protective sac will also extend and expand. In a year, July to September is the most harmful. In 1 1 month, larvae overwinter in sealed capsules. When overwintering, the larvae tie the opening of the capsule to the branches or veins of the plant with silk rings.

Spraying 90% trichlorfon stock solution 1000 times solution or 80% dichlorvos EC 1000 times solution for chemical control in early and middle July has achieved good results.

Green blind stinkbug

[symptoms]

Green-blind stinkbug harms many kinds of flowers and trees, such as roses, chrysanthemums, dahlias, bunches of red flowers, hibiscus, hibiscus, pomegranate and peach blossoms. Adults and nymphs use oral needles to harm the tender leaves, leaf buds and buds of Chinese rose and other plants. After a few days, the stabbed leaves appear black spots and holes, and when the damage is serious, the leaves twist and shrink. After the bud was stabbed, the wound oozed dark brown juice. After the tender tip of the leaf bud is killed, it is burnt black and cannot grow leaves.

[chemical control]

When a large number of nymphs hatch in the first half of April, 80% dichlorvos EC 1 1,000 times, 40% omethoate EC 1 1,000 times, 50% chlorfenapyr EC 1 1,000 times, 50% phoxim EC or 20% EC 2000 times are used to kill chrysanthemums. When spraying, pay attention to hidden places such as the back of leaves, and spray weeds nearby at the same time.

Tetranychus schrenckii

[symptoms]

Tetranychus schrenckii is a common tetranychus schrenckii on Chinese rose and Chinese rose. Sucking juice from the back of the fixed leaves of mouthparts first harms the lower leaves and then gradually spreads to the upper leaves. The damaged leaves appear gray spots or white patches, and in severe cases, the leaves die and fall off.

[chemical control]

(1) In winter, Chinese rose can be sprayed with sulfur mixture with Baume degree of 3~5 to kill overwintering mites on branches;

(2) Spraying 1000 times of 40% dicofol EC or 1500~2000 times of 50% parathion EC during the hazard period. Pay attention to fully spraying the back of leaves.