Rose ,so romantic and lovely.It is really a pleasure to plant roses.Today when you come to your beloved rose bushes, you are surprised to find that your lovely roses are covered by a dusting of white powder on buds,stems and leaves.These white powder makes your roses,once beautiful and heathy,look sick and ugly.Turns out that your roses have powdery mildew.
What is Rose powdery mildew？
Rose powdery mildew is a fungal disease.The fungus produces spores which are spread by the wind.Fortunely,it’s very easy to figure out that whether your roses have powdery.If your roses have powdery mildew,you would find out white or grey powdery spots on the buds,leaves, stems or even.When the disease is mild,the growth of rose would be weakened, the young leaves are distorted and deformed,and the flower posture grows irregular, which affects the growth and loss of ornamental value.When the disease occurs severely, it causes early deciduous leaves of rose, deformity or incomplete opening of flower buds, and consecutive diseases make the branches of rose wither or the whole plant die, seriously affecting its quality and yield.
How to prevent rose powdery mildew？
Rose powdery mildew grows well in environments with moderate temperatures and high humidity.Sounds familiar?Actually greenhouses are ideal environments for rose powder mildew to speard because of their high humidity and moderate temperatures.Of course i’m not telling you not to use greenhouses.To prevent powdery mildew ,you should ventilate your roses and increase the light conditions.High-density means high risk of diseases.With the increase of planting density,the condition of ventilation and transmittance getting worse,which makes fungi easier to spread.So don’t plant your roses in high -density.
1.Remove the infected parts
Donnot hestitate to remove the infected parts of roses after you find out powedery mildew.Throw the infected leaves and twigs away,don’t give these trash chances to infect healthy ones. Also, be careful not to touch healthy leaves with your pruning shears so as not to spread the disease .After pruning,don’forget sterilizing your pruners with rubbing alcohol.
Milk has been proved by many gardeners to be effective in treating powdery mildew of roses.You can dilute the milk with water (typically 1:10) and spray on roses at the first sign of infection, or as a preventative measure.
Baking soda is also a solution to preventing rose powdery mildew.Use about 3 teaspoons of ordinary baking soda for each gallon of water.It do prevent it from spreading to healthy leaves and allow the rose to recover.
A.Triadimefon is a fungicides with high efficiency, low toxicity, low residue, long duration and strong internal absorbability.It can be sprayed with 1000–1200 WP of 15% wettable powder, 1 times intervals of 10 days, and 2–3 times.
B.Trichoderma harzianum is a also good choice used on rose to control fungus disease with no toxicity and residues.It also can help improve soil condition.More suitable for organic garden.