Knowledge of rose pest control 1. Knowledge of rose pest control

Fungal infection:

Black spot disease: mainly affects leaves, petioles and tender shoots. When the leaves are first developed, purple-brown to brown spots appear on the front, and most of them are round or amorphous black-brown spots after expansion. Can spray carbendazim, thiophanate methyl, dyclonine and other drugs.

Powdery mildew: invades young leaves and white powder appears on both sides. Early symptoms are not obvious. After 3-5 days, the leaves are waterlogged and gradually turn green and yellow, which will cause the leaves to fall off in severe cases. Carbendazim and triadimefon can be sprayed during the onset, but Guoguang Naying has the best effect.

Leaf blight: most leaf tips or edges invade, which is yellow spots at first, and then quickly expands inward into irregular large spots. The severely damaged whole leaves withered by 2/3, and the affected parts turned green and yellow, and brown withered and fell off. In order to prevent and control the above diseases, in addition to strengthening fertilizer and water management, diseased branches and leaves should be cut off in winter, and underground leaves should be removed to reduce the initial invasion source. Comprehensive prevention and treatment should be taken when the disease occurs, and fungicides such as carbendazim and thiophanate-methyl should be sprayed.

Prevention is the main method, and fungicides are sprayed regularly in high temperature, high humidity or rainy season, and sulfur mixture is sprayed when seedlings enter dormancy period for comprehensive sterilization.

control of insect

1. stickleback moths are mainly larvae of stickleback moths, brown-edged green stickleback moths, reddish-brown stickleback moths, mulberry-brown stickleback moths and flat stickleback moths, and eat a lot of leaves in high temperature seasons. Control method: once found, spray 800 times solution of 90% trichlorfon crystal or spray 2.5% pyrethroid EC 15 00 immediately.

2. The scale insects mainly include semi-blind stinkbug, Japanese tortoise scale, red tortoise scale, brown tortoise scale, bladder scale, snake-eyed scale and so on. Its harm is characterized by sucking the juice of tender stems and leaves of Chinese rose, which leads to poor plant growth. The main control methods are: spraying 25% chlorpyrifos wettable powder with 2 000 times solution at the peak of nymph hatching.

3. Aphids are mainly Chinese rose aphids and peach aphids. They suck the sap from the tender organs of plants, hurting tender stems, leaves and buds. , and seriously affect the growth and flowering of plants. Control method: spray and kill with 2000 times 10% imidacloprid wettable powder in time.

4. Most of the sawflies are larvae, and dozens or hundreds of them are harmful in clusters. They can eat up the tender leaves of plants in a short time, leaving only a few main veins, which seriously harms the normal growth of plants. Prevention and control methods: a small number of potted plants can be picked and trampled to death when they first appear. They appear in large quantities, and 75% phoxim EC can be sprayed 4000 times.

5. Tetranychus cinnabarinus can produce 18 ~ 15 generations a year. Adults, larvae and nymphs congregate on the back of leaves, and most of the eggs are laid on both sides of veins on the back of leaves or under the gathered silk screen. Each female mite can lay 50 ~ 150 eggs, with a maximum of 500 eggs. It takes only 10 ~ 13 days to complete a generation at 23 ~ 25℃, and it takes about 7 ~ 8 days at 28℃. The high temperature and drought season often leads to a large number of dense white spots on the front of leaves, yellowing on the back of leaves, and occasional withered spots. Control method: once found, spray 2000 times of 25% belloba wettable powder to kill it.

6. Scarabs mainly include scarabs, black velvet scarabs, white star scarabs and small blue and white scarabs, which often feed on new leaves, twigs and buds with adults, seriously affecting the growth and flowering of plants. Prevention and control methods: Use the suspended animation of adults to knock them down to death at night. Using the phototaxis of adults, black light is used to trap and kill them. When adults feed on food, spray 50% malathion EC 1000 times.

2. How does the rose control pests and diseases?

Tetranychus cinnabarinus and its control are also called red spiders. There are two kinds of tetranychus cinnabarinus, insect red, tetranychus urticae and insect yellow to yellow-green.

Generally, Tetranychus urticae will parasitize on the back of leaves to suck juice, while many tiny yellow and white spots will appear on the front of leaves, and then the leaves will turn yellow slowly and finally fall off. In severe cases, the whole bud and branches will be covered by spider mites.

During the insect sting period, sulfur and the mixture of sulfur, abamectin, propargite, chlorpyrifos, chlorpyrifos, etc. can be sprayed evenly. Can be sprayed at the beginning of the disease. Aphids on Chinese rose flowers and their control will gather on the buds, tender leaves and buds of Chinese rose flowers to suck their juice. In severe cases, there will be honey-oily black secretion, which will affect the quality of flowers and the growth of Chinese roses.

When aphids lay eggs in autumn and winter, imidacloprid and avermectin can be used alternately for control. Rose thrips and control thrips will make their tips die when young leaves live, resulting in failure to grow.

If we feed on the back of leaves and excrete brown substances, the back of leaves will be deformed, and gray or taupe stripes will appear on both sides of midvein, which will be deformed and bent. Can be sprayed with drugs for treatment, such as acetamiprid, thiamethoxam, etc. Be chosen.

The leaf peaks of Chinese rose and the leaves to prevent larvae from eating into Chinese rose will produce holes, which will feed quickly and even chew the tender tips completely in severe cases. Pesticides such as phoxim and emamectin benzoate with high chlorine can be sprayed at the early stage of pest occurrence.

Rose stem bee and its control occur once a year. It lays eggs under the inner epidermis in April and May, hatches, drills into the stem, and then cuts down along the cambium spiral to eat until it reaches the lower part of the branch. After aging, it will make a pupa room on the branch, which is barrel-shaped. The effective control method is to cut off diseased branches and cut down branches until larvae are found and then eliminated.

The Chinese rose short-fronted negative locust and its control bite the leaves into many holes, with 2 generations per year/kloc-0, spawning in winter and hatching adults in May-June. It can spray chlorpyrifos 50% 1000 times, with high mortality and good effect.

3. What are the pest control measures for roses?

① Powdery mildew: It spreads fastest in the environment with much rain, high humidity, little light and poor ventilation. First, a layer of white powder grows on the tender leaves, twigs, buds and flower branches of plants, and then the disease gradually develops and entangles the young branches. In severe cases, the buds wither, the flowers are few and small, and even the plants die. Spray 70% thiophanate-methyl 1000 times solution every 20 days from April to May or from late August to early September. ② Black spot disease: it mainly harms leaves, branches and pedicels, and can occur throughout the growing season. During the growth period, 70% thiophanate-methyl 800 times solution or 75% chlorothalonil 1000 times solution can be sprayed once a week. (3) Branch blight: It occurs on branches, and it starts with reddish-purple spots, and then gradually expands. In the later stage, the lesion was dark brown with longitudinal cracks on the surface. This kind of crack is an important feature of rose branch blight, and the whole plant dies when it is serious. 800 times of 50% bactericide or 800~ 1000 times of carbendazim can be sprayed. ④ Root cancer: It is a bacterial disease, which mainly occurs in the root neck of plants, and sometimes occurs in lateral roots and branches. Tumors of different sizes occur in the susceptible parts, and the leaves on the ground of the diseased plants turn green and yellow, and the leaves are small and fall off early, which slows down the growth and affects flowering. In severe cases, plants will die. After finding the diseased plant, the tumor was removed with a knife, and then coated with ice iodine solution (mixed with 50 parts of methanol, 25 parts of glacial acetic acid and 2 parts of iodine tablets).

4. What are the common pests and diseases of Chinese rose?

There are five common diseases and insect pests in Chinese rose. The following is the introduction and prevention, provided by (Shuyang Feida Nursery Farm).

1, black spot, gray mold and downy mildew are "suspected" (leaves have black and brown spots)

Black, brown and light green spots grow on the green leaves for no reason, which is probably the initial manifestation of rose's illness, and the reasons for these situations are probably black spots, gray mold and downy mildew.

It is understood that rose black spot mainly harms leaves. In the early stage, there were black spots of different sizes on the leaves, and there were radial brown hyphae and small black spots under the cuticle of the spots. Then the spots will expand and become dark purple in yellow brown, and finally become grayish brown. In severe cases, new branches will die, and all the lower leaves of the whole rose will fall off, becoming an "army of one branch." Gray mold will occur in leaves and buds, and when it occurs at the edge and tip of leaves, it will be flooded with light brown spots at first, and then spread to rot. When the bud comes up, the diseased spot is gray-black, and the diseased bud will eventually turn brown and die. When flowers are damaged, some petals will turn yellow, shrink and rot.

Downy mildew can harm leaves, new shoots and flowers. When it occurs on leaves, irregular light green spots appear at first, then expand to yellow-brown and deep purple, and finally become taupe. The edge color is dark, gradually expanding and spreading to healthy tissues. In wet weather, sparse gray-white downy mildew layer can be seen on the back of diseased leaves.

"First of all, we must determine the cause according to the symptoms, and then prescribe the right medicine for prevention and treatment." The gardener said. When black spot occurs, it should be completely cut off and burned to reduce the source of infection. Spraying 50% carbendazim wettable powder 1000 times at the initial stage of the disease. In view of gray mold, it is necessary to clean up the diseased parts in time, reduce the source of infection, and cut off the withered rose in time. At the beginning of the disease, it can be sprayed with Bordeaux mixture. In order to prevent downy mildew, attention should also be paid to removing diseased leaves, stems and flowers, reducing the source of infection, reducing planting density and ventilation and light transmission, which can reduce the occurrence of downy mildew. When the disease is serious, it should be sprayed.

2. We can start with dead branches and root nodules (branches and roots).

Besides leaves and flowers, branches and roots of Chinese rose also send out sick signals, so you should also pay attention. It is understood that the root and branch diseases of Chinese rose mainly include dead branch disease and nodule disease.

The dead branch disease mainly harms the branches of Chinese rose, and canker spots will appear, starting in little red dot, then expanding and deepening, and finally turning brown. In the later stage, the lesion is sunken and longitudinally cracked, and black spots may appear in the affected area. When the disease is serious, the branches will wither and die. Rose nodule disease is caused by nematodes, which is characterized by white nodules at the roots, long residual period and great harm. At first, the tumor was white and elastic, and then hardened into brown or dark brown. In severe cases, nodules can grow out of the ground. Roses with nodules do not grow well and their leaves turn yellow.

In view of the dead branch disease, prevention is the main thing. First, all diseased branches are cut and burned in autumn and winter, and then cultivation management is strengthened and sufficient base fertilizer is applied. 0. 13% urea solution can be sprayed during the growth period to promote plant growth. The prevention and treatment of root nodule disease is to disinfect the roots and grafting places during planting and grafting to avoid the invasion of nematodes. At the onset, the mixed solution of methanol, glacial acetic acid and iodine tablets can be applied to the affected area to make the diseased tumor disappear.

5. How to prevent and control common diseases and pests of rose?

① Powdery mildew: It spreads fastest in the environment with much rain, high humidity, little light and poor ventilation.

First, a layer of white powder grows on the tender leaves, twigs, buds and flower branches of plants, and then the disease gradually develops and entangles the young branches. In severe cases, the buds wither, the flowers are few and small, and even the plants die. Spray 70% thiophanate-methyl 1000 times solution every 20 days from April to May or from late August to early September.

② Black spot disease: it mainly harms leaves, branches and pedicels, and can occur throughout the growing season. During the growth period, 70% thiophanate-methyl 800 times solution or 75% chlorothalonil 1000 times solution can be sprayed once a week.

(3) Branch blight: It occurs on branches, and it starts with reddish-purple spots, and then gradually expands. In the later stage, the lesion was dark brown with longitudinal cracks on the surface. This kind of crack is an important feature of rose branch blight, and the whole plant dies when it is serious. 800 times of 50% bactericide or 800~ 1000 times of carbendazim can be sprayed.

④ Root cancer: It is a bacterial disease, which mainly occurs in the root neck of plants, and sometimes occurs in lateral roots and branches. Tumors of different sizes occur in the susceptible parts, and the leaves on the ground of the diseased plants turn green and yellow, and the leaves are small and fall off early, which slows down the growth and affects flowering. In severe cases, plants will die.

After finding the diseased plant, the tumor was removed with a knife, and then coated with ice iodine solution (mixed with 50 parts of methanol, 25 parts of glacial acetic acid and 2 parts of iodine tablets).

6. How to control rose pests and diseases?

Tetranychus viennensis and its control

Tetranychus urticae is also called red spider. There are two main kinds of tetranychus cinnabarinus, namely, vermilion, tetranychus urticae, vermilion yellow to yellow-green. Generally, Tetranychus urticae will parasitize on the back of leaves to suck juice, while many tiny yellow and white spots will appear on the front of leaves, and then the leaves will turn yellow slowly and finally fall off. In severe cases, the whole bud and branches will be covered by spider mites. During the insect sting period, sulfur and the mixture of sulfur, abamectin, propargite, chlorpyrifos, chlorpyrifos, etc. can be sprayed evenly. Can be sprayed at the beginning of the disease.

Aphids of Rose and Their Control

Aphids gather on the buds, leaves and buds of Chinese roses to suck their juice. In severe cases, there will be honey-oily black secretion, which will affect the quality of flowers and the growth of Chinese roses. When aphids lay eggs in autumn and winter, imidacloprid and avermectin can be used alternately for control.

Rose thrips and its control

When thrips live in young leaves, their tips will die, resulting in no growth. If we feed on the back of leaves and excrete brown substances, the back of leaves will be deformed, and gray or taupe stripes will appear on both sides of midvein, which will be deformed and bent. Can be sprayed with drugs for treatment, such as acetamiprid, thiamethoxam, etc. Be chosen.

Leaf peak of rose and its control

Larvae eat the leaves of Chinese rose, creating holes, feeding quickly, and in severe cases, eating all the leaves and even the tender tips. Pesticides such as phoxim and emamectin benzoate with high chlorine can be sprayed at the early stage of pest occurrence.

Rose stem bee and its control

It produces one generation a year, lays eggs under the inner epidermis from April to May, crawls into the stem after hatching, and then cuts down along the cambium spiral until it reaches the lower part of the branch. After aging, it will become a pupa chamber in the branch, which is barrel-shaped. The effective control method is to cut off diseased branches and cut down branches until larvae are found and then eliminated.

Chinese rose short-fronted locust and its control

The short-fronted negative locust will bite the leaves into many holes, with 2 generations per year/kloc-0, spawning in winter and hatching adults from May to June. It can spray chlorpyrifos 50% 1000 times, with high mortality and good effect.

7. Control of rose diseases

Diseases of rose and their prevention and control methods In modern production, more than 90% of diseases and insect pests can be prevented by suitable greenhouse conditions, such as installing insect-proof nets and strengthening the ventilation environment in the greenhouse.

The deployment of professional plant protection technicians and the daily monitoring of all workers are the keys to the early detection and control of pests and diseases in the initial stage. 1. Root cancer: Root cancer is the main disease of national producers without cold winter.

The disease is widespread in Asia, Africa, Australia and India. It is said that root cancer is brought by rhizomes, but it may have existed in the soil and attached to the host when the seedlings were planted.

Control measures: chemical control and the use of resistant rootstocks can only play a preventive role to a certain extent. The only way to prevent root cancer infection is to adopt soilless culture or buy rootstocks in frost areas.

The daily control is to disinfect the seedbed soil, plant resistant rootstocks or carry out soilless culture before planting. 2. Downy mildew: Downy mildew is a headache for every tropical rose producer. It often occurs in cold and humid weather and when there is a lack of air circulation around plants.

Leaves will turn yellow after dark spots appear, and will fall off after a while. Downy mildew will do great harm to rose in a short time, resulting in serious yield reduction.

The prevention method is to keep the leaves dry, especially at night when the temperature drops. There are few treatments except ventilation. For rose, downy mildew with low temperature is not as common as powdery mildew with high temperature.

Prevention and control measures: Downy mildew can't use any preventive. When the plant gets sick, it should be sprayed three times, with an interval of 4-7 days each time. The names of the drugs are bifonazole (concentration 150ml/ 100L), Lebigeng (concentration 25-35ml/ 100L) and chloramphenicol (concentration100l).

When infected with downy mildew again, products containing other chemical components should be sprayed three times. The drug names are ethirimol sulfonate (200-300ml/ 100L water), dodecyl morpholine (200-250ml/ 100L water) and benzene preparation fungus agent. At night, the relative humidity is very high (> 90%), so it is recommended to use sulfur once a week to prevent downy mildew.

The most vulnerable period is in the rainy season and the season when the temperature needs to be lowered at night. Use the sulfur fumigator once a week, and use about 300-500 grams of sulfur per 1000 square meter.

3. Anthracnose: The pathogen is Colletotrichum roseum. The pathogen infects all parts of the aerial parts of rose plants.

On the leaves, the lesion is almost round, with a diameter of about 6 mm, and the initial lesion is purple-brown with a light brown edge.

In the later stage, the center of the lesion turns gray and often falls off. The lesions were uniformly black with irregular radial edges.

Generally speaking, anthracnose has little effect on the growth of Chinese rose. 4. Black spot disease: The pathogen is bisporus roseus.

Rose black spot is a worldwide disease, which is very harmful. Pathogens mainly harm leaves, branches and pedicels.

After infecting the leaves, purple-black circular spots or irregular (radioactive) spots appear on the leaves. The edge of the lesion is purple-brown or reddish-brown, which is radial.

There are many small black particles on the lesion, namely acervulus. Lesions are often linked together.

The mesophyll around the ward turned yellow in a large area, and the lesion became an "island" with a green edge. Sick leaves fall off easily.

When the disease is serious, all the leaves in the lower and middle parts of the whole plant fall off. The asexual stage of bacteria is the most common.

Acervulus is born under the epidermis of the host and breaks through the epidermis when it matures. Spore discs are black and arranged in a ring. Conidiophore is short, with oval or oblong conidia and colorless bisporus, and the two cells are different in size.

Black spot overwinters on diseased plants or fallen leaves as mycelium or apetalous body. Conidia are spread by rain or water spray, and insects can also spread.

Under wet conditions, conidia on leaves can germinate within 6 hours and invade directly. The incubation period is 7- 10 days.

It is easy to get sick in rainy, foggy and dewy weather. Newly transplanted seedlings have few roots, weak plants and are prone to diseases.

There are great differences in disease resistance among rose varieties, and generally light-colored flowers, small flowers and erect varieties are prone to disease. Prevention and control measures: clean up the fallen leaves on the ground at any time, thoroughly clean up the fallen leaves after autumn and burn them.

Trim the wintering plants again. Strengthen cultivation management, especially the fertilizer and water management of newly planted small plants, and improve the disease resistance of plants.

Planting or breeding disease-resistant varieties, strengthening chemical control in the early growth stage to prevent bacterial infection, such as spraying 50% amobam 1000 times solution, 50% carbendazim 1000 times solution, Bordeaux solution (1:200), etc. Improve watering facilities and control insects to reduce the spread of germs.

5. Botrytis cinerea: The pathogen is Botrytis cinerea. After botrytis cinerea infected the bud, it turned brown and rotted.

It was violated in bloom. Individual petals turn brown and wither.

Diseases easily occur on old flowers that have not been picked, especially in wet conditions and rainy season. When the disease is serious, the flowering is blocked, and gray mold exists on the dead rose in winter.

Prevention and control measures: remove diseased flowers in time, remove withered presbyopia and focus on incineration. Spraying chemicals, such as 70% thiram or 50% 1000 times benadryl, at the early stage of plant growth can effectively control diseases.

6. Powdery mildew: The pathogen is pink powdery mildew (Sphaerotheca pannosa var.rosae).

Powdery mildew can infect leaves, petioles, buds and tender shoots. At the early stage, there are chlorosis spots on the diseased leaves, which gradually expand and the edge is not obvious.

A layer of white powder is attached to the diseased spots on the back of the leaves. After the tender leaves are infected, the leaves are easy to roll back, shrink, thicken and sometimes turn purple.

After the petiole and tender tip are infected, the leaves turn yellow, shrink and fall off. When the old leaves fall off, the new leaves will continue to suffer, leading to plant weakness, abnormal flowering or inability to bloom, and loss of ornamental value.

Powdery mildew overwinters on diseased buds, diseased leaves or diseased branches as hyphae. Some overwinter in the form of closed capsules.

In the second year, the pathogen began to move with the germination of the bud, infected the shoots, produced new spores of the pathogen, and spread by wind and other means. During the growth of Chinese rose, germs can be continuously re-transmitted.

When roses are cultivated in the open field, powdery mildew occurs frequently in spring (May-June) and autumn (9-65438+1October), which is the peak of the disease. Northern region.

8. Control of pests and diseases of Chinese rose flowers

Chinese rose flowers are beautiful, diverse and fragrant, and bloom all year round. In particular, it has many varieties and is easy to breed and cultivate. Known as the "queen of flowers", it is one of the top ten famous flowers in China.

However, pests and diseases of rose often cause poor growth and even death, which seriously affects the ornamental value. Through many years' practice, the author summarized the main pests and diseases of rose and their control methods for reference.

1 The leaves, tender leaves and pedicels of rose black spot can be damaged. Lesions usually appear on the surface of leaves, nearly round or irregular, with a diameter of about 65438±0.5mm, ciliated edges, black or dark brown, and often surrounded by yellow halo.

The mycelium branches radially under the stratum corneum, which is black and purple. Black protruding pointed spots can be seen on the lesions, which are pathogenic bacteria.

Lesions are often linked together. The leaves around the diseased spots turned yellow in a large area, and the diseased spots became "islands" with green edges.

The lesions on petioles and twigs are long, and the edges are not obviously radial. In severe cases, the diseased leaves contract unevenly, the leaves curl to the back of the leaves, the shoots bend downward or die, and the buds can't unfold normally.

The pathogen is Actinobacillus fungus. Conidia are oval or gourd-shaped, bicellular and slightly bunched.

The upper layer cells are small, with beak-like processes, leaning to one side. The pathogen overwinters on the dead leaves of diseased branches as hyphae or valveless.

Conidia were produced in the following spring and spread with the wind. Humid, foggy, sultry, rainy and poorly ventilated environment is conducive to the occurrence and prevalence of diseases.

When the dew is heavy or the leaves are watered after evening, there is still water in the leaves at night, which provides favorable conditions for the occurrence of diseases and will lead to the aggravation of diseases. When there is water on the leaves, spores can germinate and invade within 6 hours.

Plants grow poorly, especially the newly transplanted seedlings are seriously ill. High planting density in open field, crowded flowerpots and sprinkler irrigation will aggravate the occurrence of diseases.

Prevention and control measures: (1) Eliminate the source of infection. Completely remove dead leaves in autumn, prune and cut off diseased branches in winter, and remove overwintering germs on diseased branches.

⑵ Frequent inspection during the onset season, timely removal of diseased leaves and destruction can prevent the spread of diseases. ⑶ Improve environmental conditions, strengthen cultivation management, improve plant disease resistance and control diseases.

It is best to use drip irrigation, furrow irrigation or watering along the basin to avoid sprinkler irrigation and prevent drip irrigation from spreading germs to adjacent leaves. Irrigation time is best in sunny morning to keep the leaves dry. Planting density and flowerpot placement density should be appropriate to facilitate ventilation; Selecting local rose varieties with strong disease resistance for cultivation; Increase the application of organic fertilizer, phosphorus, potassium fertilizer and nitrogen fertilizer to make plants grow healthily and improve disease resistance.

(4) When the new Ye Gang is launched in summer, it should be disinfected and protected until winter. Spray 1~2 times a week in rainy season and once every 7~ 15 days at ordinary times. The number of sprays depends on the development of the disease and the types of drugs.

Available chemicals include 75% chlorothalonil 500 times solution, 50% carbendazim WP 500~ 1000 times solution, 80% zineb 500 times solution, 1% bordeaux solution, or 70% thiophanate methyl 800~ 1000 times solution, etc. Among them, 75% chlorothalonil 500 times solution spray has the most remarkable control effect.

7~ 10 daily spray 1 time. In order to prevent pathogenic bacteria from developing drug resistance, chemicals must be used alternately.

Powdery mildew of rose harms leaves, shoots, buds and pedicels of rose. After the tender leaves are infected, the leaves are deformed and bent, sometimes turning purple. After the infection of the old leaves, the leaves are nearly round, and there is no obvious boundary between waterlogged chlorosis and healthy tissues. There is a white object at the diseased spot on the back of the leaf, and when it is serious, the leaf withers and falls off.

The damaged parts of shoots and pedicels are slightly enlarged, and the top ends bend to the ground. After infection, the flower buds can't open or the flower shape is abnormal.

The surface of the injured part was covered with white powder. The pathogen is Trichophyton roseum, whose mycelium develops on the host surface and penetrates into the epidermal cells of plants with haustorium to absorb nutrients.

Conidiophore is short and erect, with conidia attached to the top. Conidia are colorless, oval or barrel-shaped, with 5~ 10 series. Conidia mainly overwinter in dormant buds of infected plants, and are covered with white powder when the buds unfold in the following spring. These conidia are spread to young tissues by wind, germinate under suitable environmental conditions, and enter epidermal cells through cuticle and epidermal cell wall for harm. Powdery mildew usually occurs in warm, dry or humid environment, but rainfall is not conducive to the occurrence of the disease. Too much nitrogen fertilizer is applied, and soil is prone to calcium and potassium deficiency. Too dense plants and poor ventilation and light transmission lead to serious diseases.

Severe temperature changes, excessive drying of soil in flowerpots, etc. , will reduce the expansion pressure of host cells, thus weakening the disease resistance of plants, which is conducive to the occurrence of diseases. Control methods: (1) Strengthen cultivation management, pay attention to soil moisture and water in time; Rational fertilization, nitrogen fertilizer should not be too much, potassium and calcium fertilizer should be appropriately increased to enhance plant growth and improve disease resistance.

Timely pruning and shaping, removing diseased branches and leaves, and improving ventilation and light transmission conditions between plants. Indoor potted roses should be placed in a well-ventilated and sunny place.

⑵ Chemical control: Spraying Bomei 3~4 degree sulfur mixture before germination in early spring, and spraying 70% thiophanate-methyl 1000~ 1500 times solution or 15% triadimefon wettable powder 1000 times solution during growth period have good control effects. The duration of triadimefon can reach 20~25 days. After spraying, the white powder layer on the affected part turns dark gray, shrinks and disappears.

The author also sprayed with 1:20 lime water, and after a few minutes, sprayed with clear water, which can also effectively control powdery mildew. Aphids are mainly Chinese rose aphids and peach aphids.

Aphids gather on buds, young leaves and buds to suck juice. When it happens in large quantities, there is honey-oily black secretion.

Parthenogenesis occurs in spring and summer, oviposition overwinters in autumn, and bisexual reproduction is carried out. In open field cultivation, early spring and early summer are frequent periods.

Prevention and control methods: When the amount of insects is small, you can spray clean water for washing. If necessary, spray 4,000 ~ 5,000 times of 2.5% deltamethrin emulsion or 2,000 times of 10% imidacloprid wettable powder.

When spraying, add11000 neutral washing powder to improve the control effect. Pay attention to the protection of natural enemies such as ladybugs, grass bells and syrphids.

Scarabs mainly include scarabs, black velvet scarabs, white star scarabs and small blue and white scarabs. Adults often eat new leaves, shoots and flower buds, which seriously affects the growth and flowering of plants.

Prevention and control methods: use the suspended animation of adults to kill them in the evening; Using the phototaxis of adults, black light is used to trap and kill them; When adults feed on food, spray 50% malathion EC 1000 times. 5 scale insects.

9. What are the common pests and diseases of Chinese rose?

The following are several common diseases of Chinese rose: powdery mildew is the most common disease in 0 1, and the peak of powdery mildew is generally in spring and autumn, because the climate in spring and autumn is slightly dry. If the growth environment of rose is not well ventilated and the light is not particularly sufficient, it is easy to get powdery mildew.

Powdery mildew generally begins in the middle and upper leaves and shoots, with white powdery sticky granular powder on both sides. If you want to control powdery mildew in place, you should pay attention to keep ventilation and good light at ordinary times. When it happens, spray the plants with fungicides several times. In addition, it is recommended to use organic liquid fertilizer with balanced nutrition.

The most common pests are red spiders, scale insects, whiteflies and aphids. Red spider is difficult to be solved by ordinary pesticides. It is best to use special insecticides such as acaricide and mirex, and spray several times every 5~7 days to kill the red spider. Some flowers and dimethoate can be used for scale insects, whiteflies and aphids.

The most common yellow leaves are sunburn and lack of nutrition. If the sun is too strong, the leaves will be yellow. If you don't pay attention to supplement nutrition at ordinary times, it will easily lead to insufficient nutrition and green leaves. Individuals generally shade themselves when the sun is too strong at noon to ensure the healthy growth and flowering of Chinese roses. If you supplement nutrients, topdressing once every half a month or so, irrigate the roots with nutrient solution diluted 800 times, so that the leaves will be oily green.

As we all know, excessive watering is the most common reason, because some friends can't control the amount of water well, and it is easy to water too much if they are not careful, resulting in rotten roots and yellow leaves. Personally, I suggest that people who really don't know how to grasp the amount of water can measure it with a water detector for flowers and plants, or slowly water it along the soil with a watering can. When the water is gradually drained from the bottom of the basin, it means that it has been completely watered.

So much for sharing. Master these popular problem-solving skills to keep your rose away from disease! Warmly remind everyone that if it is a rose that has just entered the pot, don't directly fertilize it. It is suggested to wait until the buds grow out, that is, after the pot service period, and then apply fertilizer, otherwise it will easily cause root burning.