Pyrethrum has been touted for years as an all-natural insecticide, appropriate for organic gardeners or those who simply want to avoid using synthetic chemicals in their garden. Pyrethrum is
What is Pyrethrum?
Pyrethrum is an organic pesticide that is derived from a species of chrysanthemum, Tanacetum cinerariaefolium,
The Problem with Pyrethrum
The problem with using pyrethrum in your garden is that it is a broad spectrum pesticide that kills not only the thugs you may be targeting, but beneficial insects as well. In addition, pyrethrum is harmful to fish and other aquatic life, so using it near a storm drain, any body of water, or in areas where runoff is a problem is definitely not recommended. It is less toxic to mammals and birds than synthetics, but, of course less toxic
Alternatives to Pyrethrum
Try these ideas for battling insect pests in your garden before reaching for pyrethrum:
- Aphids The best way to deal with aphids is to knock them off of your garden plants with a strong blast of water from your hose. In the rare cases where this doesn't work, you can use a homemade spray made from either tomato leaves or garlic.
- Whitefly Hang sticky traps near infested plants, replace as needed. Whiteflies are attracted to tomatoes and strawberries, as well as many common annuals. Another good option for taking care of an infestation is to vacuum your plants. Seriously. Take the Dustbuster to your tomatoes, and your whitefly problem is solved.
- Potato beetle If you have a smallish patch, just look over your plants and manually remove the beetles, squishing them or dropping them into a cup of soapy water as you go. If you have a large patch, and know that Colorado potato beetles are a problem, you can dust the plants with Bt.
- Flea beetle Sticky traps are a good option here, as are floating row covers. Another good way to protect against flea beetles is to plant a trap crop, such as radishes, in your garden. The flea beetles will gravitate toward your trap crop and leave your tomatoes alone.
- Cabbage worm Hand picking is my method of choice for cabbage worms. An even better idea is to cover your Brassicas with a floating row cover as soon as you start seeing those pesky white butterflies fluttering around.
You can also practice companion planting to thwart many of the above pests, and make your garden more attractive to those all-important beneficial insects as well.
As you can see, pyrethrum isn't a terrible option, and if you are dealing with a bad infestation, there's nothing wrong with using it in moderation. However, most gardeners can take care of their pest problems using the above methods, all of which are much greener than using a broad-spectrum pesticide, even if it is an organic one.
Learn more about green gardening in our Organic Gardening feature