Systemic fungicides control most of the milder, although quite devastating fungal
diseases, such as mildew and leaf spots. They have only a marginal effect against
rusts, which are best controlled once spotted with a contact fungicide.
Apply monthly beginning in the spring.
The fungus survives winter and releases spores in spring and early summer, which infect the new growth ...
Enjoy the flowers, but don't forget to begin protecting new leaves with a systemic fungicide such as the one in Yates Rose Gun (Rose Shield is more suitable for larger rose gardens).
Second, spray with a such as Rose Clear in late Spring and again two weeks later. Spray at this time of year even though there may well be no sign of Black Spot.
Systemic fungicides are subdivided based on the direction and extent of movement inside the plant.
Propiconazole is a that can be applied at 14-day intervals, whereas chlorothalonil is a foliar protectant that should be applied every 7-10 days.
Petal Blight: Tiny, bleached out spots that spread over the entire underside of the petal is known as petal blight. Combat this issue by spraying the flowers with a systemic fungicide like Benomyl every five days while your azalea is blooming.
Sterilising by watering with armillatox or Jeyes fluid used to be a recommended treatment following the leaf cut but as this is not an approved use for the products I cannot recommend it. A is also worth trying but treated plants ...
Also a mixture of 1 Tablespoon baking soda and 1 Tablespoon horticultural oil in 1 gallon water, sprayed weekly, will help prevent the disease. Chemical controls include ferti" lome Systemic Fungicide and Rose, Flower, and Vegetable Spray (neem oil).
Contact fungicides are not absorbed into the plant, & only protect the plant where the spray is deposited; translaminar fungicides pass through the upper sprayed surface of the leaf to the bottom unsprayed surface; s are ...
See also: Systemic, Fungi, Plant, Fungicide, Soil