| Pest/Disease |
Symptoms |
Control |
| Slugs and snails |
Irregular holes in plants and slime trails visible. Damage is worst in shady, poorly drained areas. |
Keep the area well drained. Scatter slug pellets around plants. Squash them when you see them. Encourage predators such as birds and hedgehogs. |
| Leaf rollers or caterpillars |
Young leaves rolled or stuck together and large, irregular holes in the foliage. |
Pick off caterpillars if this is practical. If widespread, spray with an insecticide, e.g. Derris dust. |
| Aphids |
Young growth is distorted and weak. Leaves may be covered with a sticky honeydew. |
Several species of aphids infest ornamental plants in warm settled weather. Keep the plants well watered. If desired, spray them as soon as colonies start to appear. Pyrethrum is an organic-approved insecticide that will kill aphids. |
| Rust |
Leaves have red and yellow pustules. Very common on hollyhock, geranium, and antirrhinum. |
Pick off and burn diseased leaves. Chemical control is not practical. |
| Club root |
Roots are swollen and distorted. Above ground, the plants are small and die off earlier than usual. Often affects wallflower and stock. |
Avoid growing stock and wallflower in the same spot each year. Apply lime to the soil for wallflower as it prefers an alkaline soil. |