Moisture triggers disease

While rain is welcome, excessive moisture provides a cultural environment that gives rise to plant diseases.

Fungi causes most plant diseases, although bacteria, viruses and nematodes are also to blame. Fungi multiply by spores, which germinate rapidly on moist foliage.

Fungi feed on plant tissues and can produce symptoms such as rotting fruit, spotted leaves, mildews, molds, and stunted or wilted plants.

Fortunately, having a disease is not an automatic death sentence for plants. Proper gardening practices often provide adequate control.

If you suspect your plants are diseased, take precautions not to spread pathogens. Keep gardening tools clean, and disinfect them after each cut by dipping them in a mixture of one part bleach to nine parts water.

Next, check gardens and landscape beds for overcrowding, which reduces airflow around plants. Good airflow minimizes moisture buildup on foliage. Open garden spaces by thinning plant populations, trimming, pruning lower branches, and pulling weeds and undesirable seedlings.

The second step in getting diseases under control is eliminating diseased plant parts. Remove or cut back diseased foliage. Trim infected branches. Remove the debris from the landscape and destroy it. Do not compost diseased plant parts.

When trimming diseased parts, use disinfected pruning shears, loppers or saws. Cut well below the diseased part of the plant, making the cut back to a bud or crotch.

Be practical; don’t remove a whole branch when spraying with an appropriate product might control the issue. If a plant is so diseased that it would require major pruning, it is best to replace the whole plant. Good horticultural practices reduce the likelihood of diseases.

Plant pathogens spread easily, so avoid working in the garden when plants and soil are wet.

Remove weeds – often! Many weeds harbor diseases and disease-spreading insects.

Weeds also compete for nutrients and reduce air circulation.

Also remember that cultural problems, such as poor drainage, can cause plant symptoms that masquerade as disease.

Use chemicals as a last resort, and apply products labeled specifically for the disease you are trying to control. For example, use a fungicide to combat fungal diseases such as powdery mildew, take-all patch in lawns or black sooty mold.

For answers to your horticulture questions, please call the Texas AgriLife Extension, Hood County at 817-579-3280 and ask to speak to a Master Gardener or visit the website at