How to treat pests and diseases on roses

Aphids (there are several kinds which attack roses) are the worst pests. Colonies of green, brown or pink insects cluster together on young, sappy shoots and flower buds. Thrips, also sap-sucking insects, are just visible to the naked eye and damage both buds and flowers. Two-spotted or red spider, a small mite, infests the lower surface of leaves, causing yellowing or browning and premature ageing. Some caterpillars chew holes in leaves and others roll leaves together. There are also several scale insects that attack roses.

The most serious diseases of rose plants are black spot and powdery mildew. Black spot causes small blackened areas, yellowing leaves and premature leaf fall. Humid weather, moderate temperatures and heavy night dews favour its spread. Powdery mildew produces a white powdery growth on leaves, stems and buds. It is most active in warm (but not too hot), humid weather.

Pests and diseases can be effectively controlled by sprays of insecticides, miticides and fungicides. Many gardeners prefer to use an all-purpose rose spray to control both pests and diseases rather than use individual chemicals. A number of such all-purpose sprays and dusts are available. The specially formulated Yates Super Shield Rose Spray Concentrate or Yates Rose Gun Spray Ready to Use are recommended. After winter pruning, while bushes are still leafless, spray roses with Yates Lime Sulfur Concentrate at winter strength. It will help control fungal spores and scale.

Related products

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.

Yates Lime Sulfur - Concentrate

Forms a protective film of sulfur that kills overwintering spores and insect pests, plus helps prevent the entry of fungal infections into fruit trees and ornamental plants.