Rusts are a group of fungal diseases affecting a wide variety of plants. It is most often seen on leaves but can affect all plant parts except the roots. It appears as a colored powder and is most often noticed after being subjected to water. It later forms hair like structures which it uses to spread further spores.
Symptoms and Damage:
As its name implies it commonly appears as a rust colored powder on leaf or stem surfaces. Though rust rarely kills its host it can severely limit its growth and can easily be spread to neighbouring plants. Affected leaves will yellow and prematurely fall and over-all growth will slow or altogether stop.
This fungus produces spores which are carried by the wind, rain or by insects or birds and can quickly spread far from its source of origin. Because of the way it is spread care should be used to prevent spreading the rust infection when treating a plant with rust.
Prevention and Control of Rust
There are many benefits to avoiding chemicals when dealing with plant diseases. The harsh chemicals in some fungicides may cause more harm to an already injured plant not to mention the possible harmful effects to you or your loved ones.
✔– First choices for attempting disease control.
✔– Used when green don't solve the issue.
✔– Only use when blue options have failed and the plant cannot be discarded.
Prevention✔– As always good hygiene practices such as removing dead material from the soil and proper watering techniques as required by your plants.
Manual✔– Pruning and destroying infected areas by placing a bag over the infected area and snipping it off with a sharp and sterile pair of scissors. Wetting or disturbing the infected may spread the spores from mature areas of the fungi.
Organic✔- Neem oil spray and Baking Soda Spray may help to control rust if you are diligent about their application, sulfur is another remedy but has limited use as a cure for major infections. Just remember to test which ever you choose to use on a small area of the plant first to be sure it doesn't cause any damage.
Biological✔– Insufficient information regarding biological control of rust.
Chemical✔– The fungicides Mancozeb® and Triforine® have proven successful in helping to control the disease but may never get rid of it completely. Ask your local garden center or hardware store professional if they know of something effective.
More information on Rust:
Encyclopædia Britannica - http://www.britannica.com/EBchecked/topic/514109/rust
Wikipedia - http://en.wikipedia.org/wiki/Rust_(fungus)
Gardening Know How - http://www.gardeningknowhow.com/rust-treatment.htm