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Insect and Disease Control


Pesticides are a chemical or other agent capable of destroying fungus or insects. Herbicides destroy vegetation, miticides control mites, insecticides combat insects, and fungicides kill fungi.

Fungicides are preventative, not curative. A regular 7-10 day spray schedule is recommended for fungus protection. An all-purpose fungicide like Funginex®, Immunox®, or Daconil® will prevent mildew, blackspot, and rust. Some are more effective with specific diseases, so rosarians often rotate products in their spray program.

AphidsSystemic insecticides such as Orthene® and Isotox® are absorbed into the plant tissue and kill sucking insects such as aphids for a 3-week period. These products also contain a contact poison that kills chewing insects on contact. Less-toxic insecticides, such as insecticidal soaps and pyrethroids (the ingredients usually end in "…thrin") kill only those insects they contact, but are quite effective at reducing pest populations. Since insecticides kill good as well as bad insects, they should be used only when absolutely necessary.

Flower Fly Larve

There are a number of alternative pesticides, as well as beneficial insects, on the market that can be used to limit or control insects and diseases. Often they are hard to find in local nurseries. Contact a local consulting rosarian for more information.


Systemic granules are costly and ineffective compared to spraying; they also have no effect on diseases, only insects. Dusts can cause allergies and sometimes burn foliage.

Powdery Mildew

Early morning spraying allows the foliage time to dry. Be sure to spray the underside of the foliage, where most insects live and spores germinate. After a spray material is mixed with water, use it within a couple of hours; it loses effectiveness if kept overnight or longer. Spraying the bush and surrounding soil should begin at pruning time. Fungi and insects have been dormant and protected during winter, and by pruning time are becoming active and vulnerable to pesticides.

Choose a sprayer that produces a fine mist. Hose-end sprayers give an uneven distribution and waste expensive spray products. For a few bushes, a pistol-grip sprayer will work. For more bushes, choose a plastic pump sprayer, which range from ½ to 2 gallons in capacity.

The pesticidal products on the market have undergone stringent testing. They are safe if you use common sense and follow directions. Read and follow all labeling directions. It is illegal to use a pesticide in a manner not in accordance with the label instructions.

Ladybug Ladybug Ladybug
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