By Laura Pottorff, Colorado State University Cooperative Extension, Horticulturist and Plant Pathologist
Don't put away those garden tools just yet. There's still work to do, if you want to get next years growing season off to a good start.
Give the garden a good clean up and turn over soil to reduce insect and disease problems next year.
A variety of insects and disease-causing microorganisms survive the winter in garden debris. Clean-up helps prevent leaf spots diseases, such as rust, early blight on tomatoes and powdery mildew. Sanitation also removes debris that harbors insects, including squash and plant bugs, asparagus and flea beetles, slugs, snails, and aphid eggs.
Do not compost diseased or insect-infested plant material. Temperatures in the compost pile often don't get hot enough to kill these organisms.
Till the Soil
Turn over or mix soil layers in vegetable or flower gardens. Incorporate remaining plant debris as you till the soil. Plant material helps enrich the soil by speeding the decay of organic matter. It also disturbs or injures many overwintering pests or exposes them to freezing and predation.
Working the soil reduces soilborne disease populations such as Fusarium and Rhizoctonia, as well as cutworms, white grubs, grasshopper eggs, squash vine borer pupae, fly pupae, and flea beetles.
Examine Woody Perennial Plants
Examine ornamental and fruit-bearing trees, shrubs, and vines. Pay special attention to plants that were damaged by weather this year or by insects and diseases. Prune out all dead or damaged plant parts, and remove them from your property. This includes branches killed by borers, scale insects or canker diseases. Dead branches and stems often attract insects and diseases. Rake and remove all leaves from plants infected by leaf spot diseases.
Note heavy scale, aphid or spider mite infestations. If your trees or shrubs were injured by these insects this year, consider an application of dormant spray oil this winter or in early spring before new foliage appears.
Good management can prevent most insect and disease problems. When pest problems do appear, obtain an accurate diagnosis from a specialist before starting any kind of treatment. Contact your local Colorado State University Cooperative Extension office for this service, as well as for non-biased, research based information.
Photograph courtesy of Judy Sedbrook.
© CSU/Denver County Extension Master Gardener 2010
888 E. Iliff Avenue, Denver, CO 80210
Date last revised: 01/05/2010