Articles Written By Members and Associates

Brief notes on the control of Pests and Diseases

Healthy plants are always less susceptible to pests and diseases than unhealthy ones. Keep greenhouses and all items used in cultivation spotlessly clean, using a weak solution of Jeyes fluid. Quarantine any "suspicious" plants and all newly obtained plants.

Where an insecticide is mentioned, you will have to ask for local advice on which one to use, as one that we might recommend may not be available in your location.

Pests

Aphids, greenfly and sometimes blackfly suck the sap from young shoots causing distorted leaves and buds. Control-spray with a contact or systemic insecticide.

Capsid Bugs are small and greenish, like aphids, feed on young shoots and inject a poison which causes discolouration, distortion and blind shoots. Control - spray with an appropriate insecticide.

Cuckoo Spit (Froghopper) is a small yellowish insects hidden inside white froth which feed on new shoots and leaves. Control - spray with an appropriate insecticide.

Red Spider Mite are minute insects which feed on leaves and cause mottling on upper surface. Very fine webs under the leaves house masses of the tiny mites. Control - spray with an appropriate insecticide.

Thrips are black insects which cause silvery specks and distortion on leaves and flowers. Control - spray with an appropriate insecticide or by smoke fumigation.

Vine Weevil are a small black beetle which lays eggs in the soil which hatch into

fat, white grubs with brown heads. The grubs eat the roots of the plant, causing eventual collapse. They are very difficult to control -a heavy boot is best! The best method of control is by biological control with Nematodes in August or with an appropriate insecticide.

Whitefly are tiny white flies which lay eggs on the underside of leaves and

multiply very quickly. They suck the sap from the plant. Control using an appropriate insecticide, twice weekly to kill the young as they hatch.

Diseases

Botrytis is a grey mould which can develop on any part of the plant and will kill it if not treated. Most prevalent in cold, damp conditions. Control - keep plant and soil free of all dead material, ventilate well. Spray with a fungicide.

Fuchsia Rust is a darkish spots appear on the upper surface of leaves with orange postules on the undersides. Control - Isolate infected plants and remove and burn infected leaves.

Care - Excessive watering can sometimes cause more problems than any other factor Always err on the side of underwatering. Overfeeding can be more harmful than underfeeding.

SJ (Member)
First published in the 1997 Year Book.