Common Garden Pests and Diseases

Common Garden Pests and Diseases
Posted: 20 February 2017

Prevention is always better
Harmful insects and diseases usually attack weak unhealthy plants. As soon as you see signs of pests or diseases check whether the plants are being fed and watered correctly and are growing in suitable conditions to their needs. If there are problems, even when conditions seem to be optimal, seek expert advice. Remember pesticides can be harmful to humans and friendly insects if used incorrectly.

 Identifying the bugs
Snails and slugs cause holes in the leaves of young plants and can chew right through the stems of newly planted seedlings.
Control: put down snail bait immediately after planting and reapply until plants are older and well established

Cut worms live in the soil and only appear at night when they eat the stems of young seedlings at or just under the ground which causes the seedlings to suddenly wilt and fall over.
Control: dig cutworm bait into the soil before planting

 Beetles such as CMR beetles with their yellow on black stripes, eat large holes in the leaves and/or petals.
Control: pick off by hand where possible or spray with a suitable insecticide for chewing insects

Red spider mite can be identified as minute red dots on the underside of leaves and is a problem of hot dry conditions. Leaves turn mottled yellow and fall off prematurely.
Control: water the undersides of plants and avoid stressed plants due to lack of water and food. Spray with a suitable insecticide

Aphids are small sucking insects usually found on new growth. Their sucking of plant sap results in leaves that are distorted, curled and failing to develop.
Control: spray with a suitable insecticide for sucking insects

Powdery mildew is the white powdery deposit found on leaves stems and buds of plants such as poppies, verbena and zinnias.
Control: don’t water late afternoon or at night, make sure sun loving plants get enough light. Spray with a suitable fungicide.

Rust is the red or brown powdery substance found on the undersides of the leaves of plants such as snapdragons, calendula and Barberton daisies. This results in poor plant growth and yellow leaves.
Control: ensure plants get enough sun, avoid watering late afternoon or at night and spray with a suitable fungicide