Organic growers have used milk and baking soda with success. Simply mix half a litre of milk with two tablespoons of baking soda in five litres of water and spray liberally over foliage and stems. This formula can be applied at any time of the year.
Mix 1 teaspoon of baking soda to a quarter gallon of warm water. Add another teaspoon of liquid to the solution and give it a stir. Transfer the concoction to a bottle and generously spray the leaves of your rose plant. Rather than a cure, this remedy works best as a precaution against the fungus.
A Cornell University researcher demonstrated that a mixture developed for powdery mildew—1 tablespoon of baking soda mixed in a gallon of water, with a bit of horticultural oil or liquid soap added to help it cling to the leaves—is also effective for reducing the spread of black spot.
In spring and summer if black spot does occur there are natural remedies including making your own spray. Try mixing two teaspoons of bicarb soda in 5 litres of water, with a couple of drops of Seasol, or mixing one part milk with two parts water into a spray bottle. Shake and then spray onto the leaves weekly.
One part milk mixed with two parts water is a very effective preventative for blackspot and other fungal diseases in roses. It is thought that the lactoferrin in the milk helps to fight disease. This should be sprayed weekly during the growing season.
You may combine common white vinegar with baking soda to make a more effective spray for the black spot disease. In one gallon of water, combine a spoonful of white vinegar and a spoonful of baking soda. Add a teaspoon of canola or horticultural oil to the mixture.
Mix fat-free milk with water in a 1:1 ratio and apply it using a spray bottle. Spray the solution directly onto the clean leaves of your roses. The milk-and-water solution coats the leaves and leads to the growth of an invisible fungus that frightens off black spot!
Simply mix half a litre of milk with two tablespoons of baking soda in five litres of water and spray liberally over foliage and stems. This formula can be applied at any time of the year.
Its acidic properties are enough to eliminate aphids and their larvae but damage your roses and other surrounding plants if you spray too frequently. Although a small amount of natural aphid spray vinegar won't do too much damage to your flowers, it may hurt damage, or kill the plant if overdone.
Give each rose a teaspoon of Epsom salts. In a fortnight, new growth will form, minus blackspot on the leaves. To control diseases, roses must be sprayed each fortnight with fungicide.
There are plenty of safe and organic ways to treat black spot. Try using two teaspoons of bicarb soda in 5 litres of water, add a couple of drops of detergent or a couple of drops of seaweed extract. This makes an excellent and inexpensive fungicide. Or use Bordeaux mixture or one of the other copper based fungicides.
There is an easy way to stop and prevent black spot – Bonide Copper Fungicide QT – this spray is safe to use on roses, vegetables, fruits, and many other types of flowers. It will prevent the spread of black spot as well as other fungus such as late blight and downy mildew.
The recommended use for Diathine M-45 is a tablespoon to a gallon of water. These will last you for many sprays. We spray our roses every 7 to 10 days, and this controls the blackspot. We use both products in the same spray as one is a systemic and the other is a curative or contact.
Soap solution: Mix 1 tablespoon of unscented soap with 1 litre of water. Spray the rose over several days with this mixture. Stinging nettle decoration: Use over several days until the affected areas are free of aphids. Remove badly damaged parts of the rose.
Baking Soda.
This can act as a fungicide. Dilute 1 teaspoon to 1 quart of warm, soapy water and spray on your roses' leaves. The baking soda will treat and prevent diseases like black spot, while the soap helps it stick, and is also mildly effective at smothering many insects pests.
: Mix 3 tablespoons natural apple cider vinegar in 1 gallon water. Fill garden sprayer with the mixture, and spray the roses daily to control black spot or other fungal diseases.
Insecticidal soap and horticultural oil are also effective against rose slugs. Other insecticidal sprays that are labeled for homeowner use include acephate, bifenthrin, cyfluthrin, lambda cyhalothrin, permethrin, or spinosad. Sprays should thoroughly cover both upper and lower leaf surfaces.
You have to be careful when spraying it around certain plants as it may be harmful to some, but when used on those pesky hard-to-kill weeds, they will disappear in two to three days' time. Combine a gallon of white vinegar, one cup of salt, and a couple tablespoons of dish soap to get the job done.
Baking soda (sodium bicarbonate) is an antifungal agent and can even kill some established forms of fungus. Research has shown it's effective against some kinds of black spot and powdery mildew. 3 Best of all, baking soda is completely non-toxic for mammals, readily available in any grocery store, and inexpensive.
A good place to start is a mix of mild liquid soap and water, sprayed onto houseplants. One teaspoon of soap per litre of water will do the job. It sounds simple, but this formula will treat a lot of common houseplant pests. Add just a teaspoon of bicarbonate of soda and it becomes a great fungicide as well.
While there is no cure for infected leaves, black spot can be prevented. Existing spores overwinter on infected fallen leaves and stems, waiting for favorable conditions. The spores germinate in spring and must be continuously wet for seven hours before germination occurs.
The fungus spends the winter on fallen leaves and on the soil, and on stems and leaf buds. In spring, it produces spores that re-infect the new, young leaves. Rose black spot is worse on plants that are under stress, especially a lack of moisture at the roots, and during warm, moist weather.
The reason why milk is so effective is that it contains lactoferrin, a potent bactericide, and fungicide. Horticultural professor and author Jeff Gillman, who did extensive research on this project, instructs to use 1 part milk and 2 parts water to spray on roses once a week until the problem persists.