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Rust Fungus - natural Ways to Treat it

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10 Natural Ways to Treat Rust on Plants

Occurring mostly in mild, moist conditions, rust affects many different plants.

Left untreated, you may notice the leaves turning yellow or brown and eventually falling off [1]. Affected plants include hollyhocks, cactus, roses, monstera, beans, and tomatoes.

Chemical sprays are available to help control rust plant disease. However, for organic gardeners, there are many home remedies and natural ways to treat the problem.

Here’s how to treat rust on plants organically:

1. Baking Soda

This is a readily available domestic product that can be effective against the rust plant disease. A fungicide spray can be made up and applied to the leaves at weekly intervals until the disease is under control.

A basic solution is 1 teaspoon of baking soda in a quart of water and a little liquid organic soap. However, experts suggest adding 4 teaspoons of baking soda to 1 ounce of horticultural oil and a gallon of water.

You can also add a little white vinegar. Mix well and use as a foliar spray to help get rid of rust fungus on plants.

2. Neem Oil

This is a popular gardener’s aid that is useful as a natural fungicide for controlling rust on plants.

Neem oil sprays are commercially available online and at garden stores. Alternatively, make a homemade spray for rust on plants by combining one teaspoon of neem oil with half a teaspoon of mild liquid soap and a liter of water.

Spray affected plants, particularly the leaves, once per week to eliminate rust on the leaves. You can also use the treatment every two weeks thereafter to avoid a recurrence of the fungus.

Neem has the added benefit of eliminating insect pests that deposit honeydew, a sticky substance that encourages fungal growth.

3. Prune Infected Leaves and Branches

Rust fungi can spread to other plants of the same genus. Therefore, pruning back infected leaves and stems will help stop the spread and encourage new, healthy growth.

After pruning, clear any rusted leaves and debris from around the base of the plants. Next, give the healthy plants a protective fungicidal spray.

Also, cut back any overhanging tree branches to let in light and air. Dark, damp, and humid conditions will only encourage fungi to grow.

Pruning is the recommended control method for white pine blister rust.

4. Bonide Liquid Copper Fungicide

Absorbed in sufficient quantities, copper can kill plant cells. But Bonide is a well-tolerated product that controls rust in gardens and other fungal diseases on trees, ornamentals, and crops.

This ready-for-use copper soap spray kills rust on plants. It is also safe to use in your organic garden. However, use it according to the packaging instructions.

Spray under and on the upper surfaces of leaves and stems. Repeat every 7 to 10 days or so, depending on the degree of infection. This product works well for cedar apple rust and coffee rust.

5. Bonide Sulfur Plant Fungicide

This commercial product is formulated to prevent fungal spores from developing.

The sulfur fungicide comes in powdered form, so you can dust it on all areas of plants vulnerable to rust or mildew. Alternatively, mix it with water to make a solution that is best applied with a pressure sprayer in line with the product label guidance.

Bonide Sulfur is generally non-toxic to pets and wildlife. However, it is toxic to some aquatic creatures, so avoid using it in areas near ponds or water features.

Applied with care, this product can prevent spores of rust fungi from germinating and ruining crops.

6. Clean Up Plant Leaves and Debris

This is another important practice to help prevent rust spots on leaves from developing and spreading. The fungus can overwinter, so clear away all debris from under and around plants.

Also, remove badly infected plants entirely. Afterward, dispose of them away from the garden and not on the compost heap.

7. Avoid Overhead Sprinklers

Watering plants correctly can help keep the garden free of leaf rust. Overhead watering is likely to create the sort of moist environment that encourages the spores of rust fungi to germinate.

Overhead watering also causes splashing. Consequently, the rust can be spread through water that splashes off.

The solution is to water around the roots using a watering can or install a drip irrigation system.

8. Mulch Soil After Clean-Up

Using a thick layer of mulch will also help prevent the spores from splashing back onto the leaves.

Additionally, mulch protects the base of the plant. It also keeps the soil moist, avoiding the need to water frequently. It will keep weeds down too.

9. Space Plants Properly

An abundance of flowers growing in the garden is a joy to behold. However, overplanting can provide a breeding ground for certain pests and diseases.

Most plants thrive best with space between them. With enough space, they can absorb adequate water, nutrients, and light to develop correctly.

Fungal problems like rust can appear in dark, damp, tightly packed areas where water droplets or wind can spread spores easily.

As a result, resisting the temptation to fill every space will pay off in the long run.

10. Remove Weeds That Host Rust

Certain weeds and wildflowers can harbor rust. Wild mallow will host hollyhock rust, and willow herb is well known as a host to fuchsia rust.

Therefore, thoroughly root out the infected weeds and dispose of them. Additionally, some rust fungus spores can overwinter and germinate in the spring.

So, clear away all discarded debris with rust fungus from the garden before the gardening season arrives. You can also toss them onto the bonfire.


There are different rust diseases that can affect plants. Fortunately, most respond to natural control treatments.

Applying the organic methods above can help eliminate rust fungi effectively and in the long term.

See also: eliminating powdery mildew naturally.

Picture via Lee Reich/AP Images

Sasha Brown

Sasha Brown is a blogger and lover of all things natural.

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