Rose is infected with powdery mildew and red spider in summer, which causes some leaves to turn yellow. How to prevent it?

In summer, Chinese rose flowers are vulnerable to insect pests. Among them, red spider is a common problem, so what should I do after Rose suffers from powdery mildew and red spider? Today, I will share with you some dry goods, how to prevent powdery mildew and red spider from appearing in rose flowers, and how to prevent them after they appear.

Symptoms of Powdery Mildew Powdery Mildew is a common disease during the maintenance of Chinese rose. Powdery mildew is a common disease caused by germs, which mainly occurs on leaves, flower stalks and flower buds. At the beginning of the disease, yellow-green spots will appear on the leaves. Later, it gradually expanded and finally formed a layer of white powder. In severe cases, the whole leaf is covered with a layer of white powder. After the rose gets sick, the leaves will curl and deform, and will not bloom or deform. In severe cases, the leaves will wither and fall off, which will eventually lead to the death of the plant.

Excessive nitrogen fertilizer is the cause of powdery mildew of rose.

Spring is the peak season for the growth of Chinese rose. At this time, it is necessary to ensure adequate fertilizer. However, when fertilizing, if the nitrogen fertilizer is applied too much, the branches will grow too fast, and the leaves of the newly grown branches will be soft and tender, which is very easy to get powdery mildew. Therefore, we need to avoid using nitrogen fertilizer with high nitrogen content when applying fertilizer. It is best to use potassium dihydrogen phosphate, because potassium dihydrogen phosphate contains a lot of phosphate and potash fertilizer, and the liquid surface absorption rate is relatively high. In addition, phosphorus and potassium fertilizer will increase the stress resistance of Chinese rose, and at the same time promote the differentiation of flower buds, so that the newly grown branches can be lignified quickly.

Poor ventilation, insufficient light

The second cause of powdery mildew of rose is poor ventilation and insufficient light. Especially in spring and autumn, because spring and autumn are the peak seasons for the growth of Chinese rose flowers. At this time, if the ventilation is not smooth enough or there is insufficient light, then the rose is prone to powdery mildew. Especially for some friends who maintain Chinese roses indoors, the chances of getting sick will be higher. Therefore, in the process of maintaining the rose, we must ensure smooth ventilation and sufficient light to avoid the rose suffering from powdery mildew. If the rose is maintained indoors, it is best to put it on the balcony of Chaoyang for maintenance, and at the same time, it is necessary to open the window frequently for ventilation, so that the probability of the rose suffering from powdery mildew will be reduced.

Exposure after rain

Chinese rose usually suffers from powdery mildew in poor ventilation and high temperature and humidity environment. For roses planted outdoors, the weather suddenly clears up after heavy rain, and the rose plants are exposed to the sun, which is also easy to be infected with powdery mildew. Because Chinese rose is easy to get sick in high temperature and high humidity, we need to move the plants to a ventilated and cool place for maintenance after heavy rain. If it is planted in the ground, we need to do a good job of shading in time, which can effectively avoid the occurrence of powdery mildew.

How to Prevent Rose from Suffering from Powdery Mildew In the maintenance process of rose, in order to prevent rose from suffering from Powdery Mildew, it is necessary to strengthen cultivation management, prune in time and improve the ventilation and transparency of plants. At the same time, it is necessary to ensure sufficient light, because Chinese rose flowers must have sufficient light during the growing period, and it is best for plants to receive light for more than six hours every day. If the light is not enough, the chance of getting sick will be great, and it may also lead to the phenomenon that the flowers in the moon will not bloom. In addition, we need to strengthen the management of water and fertilizer. When applying fertilizer, mainly apply phosphorus and potassium fertilizer, and avoid using nitrogen fertilizer. Finally, after the heavy rain, we need to shade the Chinese rose flowers and can't accept the sun exposure.

How to Prevent Rose from Getting Powdery Mildew In the process of maintaining rose, we need to learn how to prevent rose from getting powdery mildew first. If the rose has already suffered from powdery mildew, we need to use it directly, otherwise the longer it is delayed, the worse it will be for the growth of the plant. If it is the early stage of the disease, we can spray the plants with 50% carbendazim wettable powder and water 1000 times solution. You can also spray plants with 70% thiophanate methyl solution with water 1000 times. In the middle and late stage, 20% triadimefon EC can be diluted with 2000 times water, or 50% polysulfide suspension can be diluted with 300 times water. In addition, it should be noted that spraying must pay attention to good technology. Be sure to spray more water on the back of the leaves first, so that the flora can be washed away, and then spray on the front, so that the liquid medicine can be left on the leaves. If it is only sprayed on the surface of leaves, the flora remaining on the back of leaves will easily spread again.

The symptoms of the red spider Chinese rose are bright and colorful. There are many friends who like Chinese rose, but Chinese rose is also a famous medicine jar, among which red spider is one of the main pests. Especially in the first year, after the Chinese rose suffers from red spider, the probability of suffering from red spider in the second year is also very high. Because the eggs of red spider can be parasitic on the plants of Chinese rose for the winter. When the temperature rises, eggs hatch into worms, and then they will come out to harm plants. After becoming a red spider, yellow spots will appear on the leaves of Chinese rose. Later, it gradually expanded and finally became a piece. If it is not treated in time, the leaves will fall off easily, and in severe cases, the plants will die, because the red spider mainly feeds on the juice of the leaves. In addition, the excrement of red spider will destroy chlorophyll. When chlorophyll is destroyed, the leaves will turn yellow and fall off easily. Moreover, Starscream has a strong spreading power. If it is not treated in time, a large area of spider webs will easily appear on the rose plants.

The cause of red spider in rose is poor ventilation and humid environment.

Rose suffers from red spider basically because there is a problem with the conservation environment. Especially in the case of poor ventilation and humid environment, it is easy to get starscream. Because the high temperature and high humidity environment is very suitable for the breeding of red spiders, for friends who maintain Chinese rose flowers indoors, if the ventilation is not smooth for a long time, it will provide a good growth environment for red spiders. In addition, when watering, you must water it in moderation, and don't overdo it. If you water too much, the soil will accumulate water and the temperature will be high, which will also induce the invasion of red spider.

The temperature is very high.

Rose has a high probability of suffering from red spider in summer, because the temperature is higher and there is more rain in summer. Starscream breeds very fast in dry and humid environment. Chinese rose likes warm climate, and the optimum temperature for its growth is between 15 ~ 28. Too high or too low temperature will affect its growth. If the rose does not grow well, the ability to resist pests and diseases will decline.

How to prevent Chinese rose from being attacked by red spider? In the maintenance process of Chinese rose, in order to prevent Chinese rose from being invaded by red spider. First of all, we need to ensure a good ventilation environment. Especially for the indoor maintenance of rose, it is necessary to open the window frequently and cut off some branches that are too dense and too long to effectively improve the ventilation conditions of rose and effectively prevent the harm of red spider. In addition, when watering, you must follow the principle of seeing dry and seeing wet. If the environment for maintaining Chinese rose flowers is too humid, it is easy to cause root rot and powdery mildew. In addition, summer must provide suitable temperature for Chinese rose. Whether it is indoor or outdoor maintenance, as long as the temperature exceeds 30, we need to shade the rose properly and often spray water on the leaves of plants to reduce the air temperature and the chance of getting sick.

How to prevent Chinese rose from suffering from red spider? After Chinese rose is replaced by red spider, we need to isolate plants first, because red spider spreads very fast. Then cut off the diseased branches and leaves and destroy them centrally. Then dilute the spray with 20% dicofol EC and 1000 times of water, or dilute the spray with 73% propargite EC and 2500 times of water, spray once every half month and spray for two or three times continuously. The effect is very good.

The above are the main reasons why the yellow leaves of Chinese rose are infected with red spider and powdery mildew and the corresponding solutions, hoping to help flower friends.