In the early nineteenth century the poet John Keats immortalised autumn as the "season of mists and mellow fruitfulness". His poem was about Southern England, but still relevant here; we're also gifted with abundant atmospheric moisture during autumn.

Fungi thrive in warm, damp conditions, so it’s easy to see why this is the time of year to watch out for garden diseases. 

Fungi spread by means of tiny dust-like particles called spores. Fungi produce literally billions of them every day! Fascinatingly, spores have the ability to use raindrop splashes to launch themselves into air currents, meaning our gardens are constantly filled with spores circulating through the air. If they land on a compatible target plant, the spore can germinate and develop into fungus: but only if there’s moisture around. Hence autumn mists, dew, showers and breezes play a big role in encouraging the spread of fungal pathogens. 

Here are some of the most common fungal diseases that are found in the garden: 

Powdery Mildew 

Named after the powdery coating that spoils new shoots and leaves, powdery mildew affects plants like roses, cucurbits (pumpkin relatives), hydrangeas, azaleas, and apples.  

Yates Natures Way Fungus Spray provides effective control of powdery mildew and is suitable to be applied to vegetables, including tomatoes. For non-edible plants such as roses or sweet peas, Yates Rose Gun Spray Ready to Use is a good choice for treating powdery mildew on roses and other ornamentals. 

Downy Mildew 

Downy Mildew is often more widespread in younger plants and is diagnosed by downy-looking whitish tufts on the underside of the leaves and circular, yellow 'oil spots' on the upper side of leaves. Downy mildew is common on grapes, vine crops, cabbages and other crucifers, onions, lettuce and stocks.

As described above, nearby plants can be quickly infected by spores on plant foliage being splashed with water. Make certain to carefully water the soil at the base of plants only, to keep the foliage as dry as possible. Treat downy mildew with Yates Liquid Copper Fungicide


Leaf Spot 

The most notorious leaf-spotting disease is black spot, the scourge of rose plants. The spores of this disease need to sit on a moist surface for about seven hours before they can germinate, so one of the best ways to prevent its development is to keep the leaves dry. Always water roses in the morning and allow the leaves to dry out through the day. From early spring, spray every two weeks with Yates Rose Gun Spray Ready to Use, alternating with Yates Liquid Copper Fungicide Concentrate. Prune to increase air movement through plants.


Rust gets its name from the yellow/orange pustules that appear on the foliage. There are hundreds of different rust diseases and they affect a wide range of plants. Use Yates Rose Gun Spray Ready to Use to treat rust. 

Leaf Curl 

Leaf Curl is a fungal disease which affects Nectarines, Peaches, Plums and Almonds. The disease overwinters in the bark and buds. For most stone fruits, one or two well timed applications of Yates Liquid Copper Fungicide should control the disease. It's usually treated in winter, but if the problem was severe in the previous season, an extra autumn application after leaf drop is recommended. Follow label instructions for correct timing of the fungicide spray, as this varies between stone fruit varieties.

Root Rot 

Usually caused by a disease with the tongue-twister name Phytophthora, this problem moves up from the roots to cause dieback in leaves and stems. It affects plants like snapdragons, leucadendrons, loquats, passionfruit and many others. Poor drainage can exacerbate the problem, so try to avoid growing susceptible plants in heavy or clay soils. Improve drainage by incorporating generous quantities of organic matter like Yates Dynamic Lifter Organic Plant Food and compost. Destroy infected plants (definitely don't put infected plant material in your compost).

Related products

Yates Nature's Way Fungus Spray

Protects against a very wide range of fungal and bacterial diseases. It is formulated from copper and sulfur, which are naturally occurring compounds.

Yates Rose Gun Spray - Ready to Use

A combination of systemic fungicide and contact insecticide. Kills pests and mites on contact and works from within the plant to control black spot, powdery mildew and rust on roses and ornamentals in the home garden.

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