Pyrethrum is a natural pesticide made from the dried flowers of the pyrethrum daisy (Chrysanthemum cinerariaefolium). The dried flowers are ground, and the powder or spray applied directly to the insects, which are immediately killed or paralyzed. The use of pyrethrum as a pesticide began more than 2,000 years to control lice and other pests. Does this Spark an idea?
How It Works
Pyrethrum works in several ways. It interferes with insects ability to find food by a process called jamming if close proximity to the target pest. Once pyrethrum directly contacts the insect, the active ingredient in pyrethrum enters the insect's body and affects the nervous system, paralyzing the insect causing it to act erratically. Pyrethrum also causes insects to leave places where they seek cover, so they are immediately exposed to the active ingredients in the pyrethrum or to a more powerful pesticide used in conjunction with the pyrethrum powder.
Insects Affected
All soft-bodied insects are either killed or paralyzed by natural pyrethrum powder. The list includes flies, moths, worms and caterpillars. It also kills beneficial and pollinating insects such as bees and butterflies. Insects with hard shells, such as grasshoppers, are less affected by pyrethrum applications.
Application
Pyrethrum is applied as a aerosol, spray or a powder. Aerosols provide fast knockdown of flying insects, such as flies. Remember that aerosol sprays may contain an agent, such as alcohol, which can damage plants. Powders are dusted over the tops and bottoms of the plants' leaves, either manually or with a special dusting tool. There are water-soluble pyrethrum powders that can be mixed with water in a garden sprayer and applied on plants.
Environmental Concerns
Long-term pyrethrum toxicity is not a problem because it does not linger in the environment. The potency rapidly decreases when the powder or spray is exposed to sunlight and heat. A tolerance to pyrethrum is not seen in the insect populations where it is often used. Pyrethrum has a long history of safe use around humans and animals.
Pyrethrum, Pyrethrin, and Pyrethroids
There is confusion concerning the difference between pyrethrum, pyrethrin and pyrethroids. Pyrethrum is the powder that comes from the ground flower parts of the pyrethrum daisy. Pyrethrins are the six compounds found within the pyrethrum powder responsible for killing insects. Pyrethroids kill insects in the same way as pyrethroids, but are chemically based and do not come from the pyrethrum daisy.
Tags: pyrethrum daisy, dried flowers, insects such, killed paralyzed, powder spray, pyrethrum powder