Dealing with Rose Disease

Image by .Annna via Flickr

Rose bushes are prone to be attacked mostly by four major diseases. Gardeners must be on the alert and be prepared on the different methods of eliminating each enemy.

Black Spot

Black Spot is a water-borne fungus which appears as small black spots on leaves and stems. If left unchecked the leaves will turn yellow, drop and the plant possibly could die.

Preventative measures against Black Spot are to only water the roots of the plants making certain that splashes do not fall onto the leaves or stems. This disease is prevalent during rainy seasons where you lack water control. Therefore it is essential to spray a fungicide at the beginning of summer and twice weekly if rainfall is high, if not every ten days. A more organic treatment is to use neem oil as a substitute. When the black spot is first discovered, remove infected fallen leaves as well as diseased leaves on the plant and destroy them.

Powdery Mildew

This is another fungus carried by wind during humid conditions, causing leaves to curl and turn purple, stems to be stunted in growth and buds failing to open. Preventative measures are to prune all effected stems before spring and subsequent growing period. Once again all diseased foliage should be destroyed. A weekly spraying of fungicide is the only treatment especially concentrating on new growth and buds.

Rust

Rust also a fungus appears as raised red-orange spots underneath leaves and yellow spots on leaf top. Stems can also be infected, but show longer thinner blemishes. Rust thrives in cool moist weather; therefore plants living in hot dry conditions will escape this disease. If left untreated all the leaves eventually turn black and fall. Treatment and preventative measures are, to space out plants adequately and thin out their foliage causing air circulation which helps to keep plants dry. Spray infected leaves and stems with Fungicide soap and again remove and destroy rusted leaves.

Spider Mites

Spider Mites favour warm dry conditions and live off mostly the underside of rose leaves. After breaking the surface of the leaf with their mouths, they use their saliva to dissolve and ingest the cells of the leaves causing them to turn yellow and if left, will damage the whole plant. Insecticides can be used; a good drenching of the entire plant early morning and evening can wash them off the plant. They do not have the ability to climb back on.

Aphids

Aphids love rose plants and simple in their hundreds suck dry the sap and if not eradicated will kill the plant. Treatment, ants and aphids are mutual friends, so get rid of marauding ant populations and you will help curb spread of aphids. It is not recommended to use chemicals to dispel them, as they are very harsh to the environment. Organic recipes such as soapy dish wash might do the trick, but if you are desperate gentle natural spray called Pyrethrem will get rid of the little beasts.