Control pests with environmentally-friendly substances derived from natural sources.

Delphinium seedlings are prone to damping-off disease.

The sowing instructions for the delphinium seed I ordered from New Zealand recommend adding a fungus to the germinating mix. Say again? Researchers discovered that a beneficial trichoderma fungus protects plant roots from other, disease-causing, fungi. The trichoderma fungus grows on the seedlings’ roots and prevents damping off and root rot, both of which are caused by pathogenic fungi. The product containing trichoderma, Rootshield®, is safe to use on all vegetable and garden plants, trees, bulbs, and houseplants. It’s one of the new environmentally-friendly biopesticides derived from natural sources. According to the U.S. Environmental Protection Agency (EPA), biopesticides are “certain types of pesticides derived from such natural materials as animals, plants, bacteria, and certain minerals. For example, canola oil and baking soda have pesticidal applications and are considered biopesticides.”

More gardeners are familiar with the group of Bt or Bacillus thuringiensis biopesticides used to control white grubs in their lawns, Colorado potato beetles, and mosquitoes. These beneficial bacteria infect and kill the target insects without harming any other organisms or polluting the environment. The beauty of Milky Spore, the bacteria that kills Japanese beetle grubs, is that it multiplies in the soil and can remain effective for up to 20 years.

Other biopesticides include beneficial nematodes, which are microscopic wormlike organisms that prey on insects, such as Japanese beetle grubs and cutworms. Nematodes even work on fungus gnats, those annoying and destructive little black bugs that infest houseplant soil.

I’m starting more vegetable and flowers from seed this year and Rootshield will help ensure that those seedlings will be strong, vigorous, and ready for the garden this spring.

For more information on natural pest control, see the Pest and Disease Finder.

Ann Whitman

Horticulturist, Gardener’s Supply