Common diseases and control of primroses

Symptom: whole plant disease caused by cucumber mosaic virus CMV. The symptoms are that the leaves become smaller and deformed, with dark green markings or yellowing. The infected plants do not blossom, or blossom, and the flowers are short and deformed with markings (see figure 1). The main route of transmission is peach aphid and cotton aphid. The main source of infection is the susceptible plants of surrounding weeds. Symptoms: most of them occur in the spring of the four seasons. It is caused by Alternaria of the subphylum Alternaria. There are brown spots on the leaves of infected plants. The route of transmission is that conidia are transmitted by wind and rain. Symptom: it is one of the common diseases of primrose, which occurs all over the country. After the plant was infected, the whole plant yellowed and withered. The disease mainly infects leaves, tender stems, floral organs and so on. It often occurs at the tip and edge of the leaf. At the beginning of the disease, the leaves appeared water-immersed spots, and then gradually expanded, turned brown and rotted. In the later stage, a gray-yellow mildew layer was formed on the surface of the lesion. After the stem was infected, the disease spot was brown and gradually rotted. After infection, the floral organ also became brown and rotted and fell off. Under moist conditions, a gray mildew layer appears in the disease, which is a major feature of the disease. The disease overwinters with sclerotia in the remnant and soil. The disease is easy to occur when the air temperature is about 20 ℃ and the air humidity is high. Spread through wind and rain, tools, irrigation water. In the greenhouse, the disease is the most serious in late winter and early spring.

Fourth, primrose spot disease 5. prevention and control methods of primrose bacterial leaf spot: strengthen cultivation management, cultivate disease-free seedlings, seedling bed soil should be disinfected; timely ventilation should be released in the greenhouse to reduce air humidity. Remove the remains of the diseased plant in time. After the attack, 50% copper succinate wettable powder or 72% agricultural streptomycin wettable powder 4000 times were sprayed. Prevention and control method: the loam rich in iron should be selected in the basin soil. Mixing ferrous sulfate and zinc sulfate into organic fertilizer can promote the development of root system and increase the ability of iron absorption. When iron deficiency occurs, 0.2 to 0.5% ferrous sulfate solution can be sprayed, which is better than directly applying it into the soil.

Common diseases and control of primroses

Primula is a perennial herb of Primulaceae, which contains many species that bloom in winter and spring. Its plants can produce a large number of beautiful flowers, which are very rich in color in the middle of the leaves. The author now introduces the common diseases of primrose as follows.

Primula mosaic disease

Symptom: whole plant disease caused by cucumber mosaic virus CMV. The symptoms are that the leaves become smaller and deformed, with dark green markings or yellowing. The infected plants do not blossom, or blossom, and the flowers are short and deformed with markings (see figure). The main route of transmission is peach aphid and cotton aphid. The main source of infection is the susceptible plants of surrounding weeds.

Prevention and control methods: first of all, it is necessary to remove weeds in time and reduce the source of infection. Secondly, aphids should be prevented and controlled as soon as possible to eliminate virus transmission vectors.

Brown spot of primrose

Symptoms: most of them occur in the spring of the four seasons. It is caused by Alternaria of the subphylum Alternaria. There are brown spots on the leaves of infected plants. The route of transmission is that conidia are transmitted by wind and rain.

Prevention and treatment: spray 70% chlorothalonil wettable powder 1000 times liquid and other fungicides at the initial stage of the disease. Primula gray mold

Symptom: it is one of the common diseases of primrose, which occurs all over the country. After the plant was infected, the whole plant yellowed and withered. The disease mainly infects leaves, tender stems, floral organs and so on. It often occurs at the tip and edge of the leaf. At the beginning of the disease, the leaves appeared water-immersed spots, and then gradually expanded, turned brown and rotted. In the later stage, a gray-yellow mildew layer was formed on the surface of the lesion. After the stem was infected, the disease spot was brown and gradually rotted. After infection, the floral organ also became brown and rotted and fell off. Under moist conditions, a gray mildew layer appears in the disease, which is a major feature of the disease. The disease overwinters with sclerotia in the remnant and soil. The disease is easy to occur when the air temperature is about 20 ℃ and the air humidity is high. Spread through wind and rain, tools, irrigation water. In the greenhouse, the disease is the most serious in late winter and early spring.

Prevention and control methods: planting density should be reasonable. Pay attention to ventilation and reduce air humidity. Diseased leaves and diseased plants are removed in time to reduce the source of infection. At the initial stage of the disease, 1500 times of 50% Sukeling or 50% Prohydantoin wettable powder was sprayed. It is best to apply alternately with 65% carbendazim wettable powder 500 times to prevent drug resistance.

Primula spot disease

Symptoms: mainly harmful to plant leaves. The disease spread from the lower part of the plant to the upper part. The spot is usually 3 to 4 mm in diameter, brown, and in severe cases, the diseased leaves die, resulting in fallen leaves. The disease is caused by Alternaria alternata. The pathogen overwintered on the diseased residue by mycelium or conidium, and the seeds could also carry bacteria, which became the source of initial infection in the second year. The disease is mainly spread by conidia in the air and Rain Water. Re-infection is frequent in the growing season. Plants are usually prone to disease in warm and humid weather and partial application of nitrogen fertilizer. The disease usually begins in July and is prevalent from August to October.

Control methods: select disease-resistant varieties, strengthen fertilizer and water management, increase the application of organic fertilizer and phosphorus and potassium fertilizer, and avoid partial application of nitrogen fertilizer. At the initial stage of the disease, 70% methyl topiramate was sprayed with 1000 times solution plus 75% chlorothalonil wettable powder 1000 times solution, or 1 ∶ 1 ∶ Bordeaux solution.

Bacterial leaf spot of primrose

Symptoms: most of the disease occurred on leaves and receptacles. At the initial stage, water-immersed irregular spots were produced along the leaf veins, then yellowed and browned, the lesions enlarged and the leaf margin dried up. In severe cases, it withered from the lower lobe.

Prevention and control methods: strengthen cultivation management, cultivate disease-free seedlings, seedling bed soil should be disinfected; timely ventilation should be released in the greenhouse to reduce air humidity. Remove the remains of the diseased plant in time. After the attack, 50% copper succinate wettable powder or 72% agricultural streptomycin wettable powder 4000 times were sprayed.

Iron deficiency yellow leaf disease of primrose

Symptoms: the young leaves in the upper part of the plant first lost green, while the old leaves were still normal. The mesophyll of the green leaves turns yellow and the veins remain green. In severe cases, brown spots appear on the leaf tip, or even fall off.

Prevention and control method: the loam rich in iron should be selected in the basin soil. Mixing ferrous sulfate and zinc sulfate into organic fertilizer can promote the development of root system and increase the ability of iron absorption. When iron deficiency occurs, 0.2 to 0.5% ferrous sulfate solution can be sprayed, which is better than directly applying it into the soil.

Primula is a perennial herb of Primulaceae, which contains many species that bloom in winter and spring. Its plants can produce a large number of beautiful flowers, flowers cluster in the middle of leaves, and the flowers are very rich in color. The author now introduces the common diseases of primrose as follows. Symptom of primrose mosaic disease: whole plant disease caused by cucumber mosaic virus CMV. The symptoms are that the leaves become smaller and deformed, with dark green markings or yellowing. Infected plants do not blossom, or flowering, flowers are also short and deformed, with markings. The main route of transmission is peach aphid and cotton aphid. The main source of infection is the susceptible plants of surrounding weeds.

Prevention and control methods: first of all, it is necessary to remove weeds in time and reduce the source of infection. Secondly, aphids should be prevented and controlled as soon as possible to eliminate virus transmission vectors. Primrose brown spot symptoms: mostly occur in the spring of the four seasons. It is caused by Alternaria of the subphylum Alternaria. There are brown spots on the leaves of infected plants. The route of transmission is that conidia are transmitted by wind and rain. Prevention and treatment: spray 70% chlorothalonil wettable powder 1000 times liquid and other fungicides at the initial stage of the disease. Primula botrytis botrytis symptom: it is one of the common diseases of primrose, which occurs all over the country. After the plant was infected, the whole plant yellowed and withered. The disease mainly infects leaves, tender stems, floral organs and so on. It often occurs at the tip and edge of the leaf. At the beginning of the disease, the leaves appeared water-immersed spots, and then gradually expanded, turned brown and rotted. In the later stage, a gray-yellow mildew layer was formed on the surface of the lesion. After the stem was infected, the disease spot was brown and gradually rotted. After infection, the floral organ also became brown and rotted and fell off. Under moist conditions, a gray mildew layer appears in the disease, which is a major feature of the disease. The disease overwinters with sclerotia in the remnant and soil. The disease is easy to occur when the air temperature is about 20 ℃ and the air humidity is high. Spread through wind and rain, tools, irrigation water. In the greenhouse, the disease is the most serious in late winter and early spring. Prevention and control methods: planting density should be reasonable. Pay attention to ventilation and reduce air humidity. Diseased leaves and diseased plants are removed in time to reduce the source of infection. At the initial stage of the disease, 1500 times of 50% Sukeling or 50% Prohydantoin wettable powder was sprayed. It is best to apply alternately with 65% carbendazim wettable powder 500 times to prevent drug resistance. Symptom of primrose spot disease: mainly harms plant leaves. The disease spread from the lower part of the plant to the upper part. The spot is usually 3 to 4 mm in diameter, brown, and in severe cases, the diseased leaves die, resulting in fallen leaves. The disease is caused by Alternaria alternata. The pathogen overwintered on the diseased residue by mycelium or conidium, and the seeds could also carry bacteria, which became the source of initial infection in the second year. The disease is mainly spread by conidia in the air and Rain Water. Re-infection is frequent in the growing season. Plants are usually prone to disease in warm and humid weather and partial application of nitrogen fertilizer. The disease usually begins in July and is prevalent from August to October. Control methods: select disease-resistant varieties, strengthen fertilizer and water management, increase the application of organic fertilizer and phosphorus and potassium fertilizer, and avoid partial application of nitrogen fertilizer. At the initial stage of the disease, 70% methyl topiramate was sprayed with 1000 times solution plus 75% chlorothalonil wettable powder 1000 times solution, or 1 ∶ 1 ∶ Bordeaux solution. Symptoms of bacterial leaf spot of primroses: mostly on leaves and receptacles. At the initial stage, water-immersed irregular spots were produced along the leaf veins, then yellowed and browned, the lesions enlarged and the leaf margin dried up. In severe cases, it withered from the lower lobe. Prevention and control methods: strengthen cultivation management, cultivate disease-free seedlings, seedling bed soil should be disinfected; timely ventilation should be released in the greenhouse to reduce air humidity. Remove the remains of the diseased plant in time. After the attack, 50% copper succinate wettable powder or 72% agricultural streptomycin wettable powder 4000 times were sprayed. The symptom of iron deficiency yellow leaf disease of primrose: the tender leaves in the upper part of the plant first lost green, but the old leaves were still normal. The mesophyll of the green leaves turns yellow and the veins remain green. In severe cases, brown spots appear on the leaf tip, or even fall off. Prevention and control method: the loam rich in iron should be selected in the basin soil. Mixing ferrous sulfate and zinc sulfate into organic fertilizer can promote the development of root system and increase the ability of iron absorption. When iron deficiency occurs, 0.2 to 0.5% ferrous sulfate solution can be sprayed, which is better than directly applying it into the soil.