1 October 2007
Virginia Cooperative Extension, Charlottesville/Albemarle County Office
460 Stagecoach Road, Charlottesville, Virginia 22902
phone: 434.872.4580 fax: 434.872.4578
By the end of September, many Virginia gardeners are wrapping up the garden season. With a little care now, gardening can be easier and more rewarding in future seasons. Vegetable and fruit production from many home gardens may be going downhill with fall weather settling in, but to many of the arthropod pests that you have battled throughout the summer, your garden can still be a pest paradise. While you are preparing your gardens for winter you should also take stock of your pesticides and other garden chemicals. If there are things that need to be stored or recycled make sure you understand what is best for you and the environment.
Although we have taken most of what we consider to be the edible portions of these plants, these pests can still find food and shelter among the aging plants and weeds. Many insect pests are able to complete development in these crop residues long after the last fruits are picked. Some acquire disease-causing organisms that they can used to infest young plants next year. Rank weed growth after harvest can also attract certain pests that may create problems for next season.
Several of the more serious insect pests such as squash vine borer, Mexican bean beetle, squash bug, and tomato hornworm are able to continue development on crop residues in the garden long after we take what we consider to be the edible vegetables and fruit. Other pests can find food and shelter from weeds as well as crop residues throughout the winter. The two-spotted spider mites continue to feed on weeds after the crops have withered.
Destruction of crop residues shortly after harvest is recommended to discourage these pests from completing their fall development. Many insects need to attain a certain size or stage in order to survive the winter. Removal of crop residues may also reduce pest survival by exposing some of them to the winter elements. These weeds and crop residues will insulate these pests from frosts and freezes.
Destruction of cucumber and melon residues not only reduces food and shelter for cucumber beetles, but also reduces the acquisition of the bacterial wilt disease organism by the overwintering beetle generation. It is the bacterium that causes bacterial wilt that is stored in the gut of cucumber beetles this winter that will start the disease cycle next year.
A thorough fall cleanup should help to discourage some of the pests that may cause problems next year. Home gardeners can compost or till these residues into the soil.
If the compost pile is active and heating adequately, adding diseased and pest-infested materials is recommended. If you are unsure that the pile is heating properly, mix the diseased and insect-infested plant debris with water to make compost tea. Disease-infested plants can also be turned into the soil in an area of the garden where susceptible plants will not be grown, such as the flower or herb garden.
Fall is an excellent time to incorporate organic matter into the garden soil. Chop and turn under dead plants and leaves, compost, composted manures and leaf humus. Plant a cover crop to help prevent erosion and to further improve soil tilth. Ideally, the garden should be clean and green when November arrives. Cover crops should be turned under before they go to seed or two weeks before crop planting in the spring.
It is important to keep in mind that this should not be just a fall practice to destroy crop residues, as soon as a crop has been harvested for the last time, clean up should begin, even if that is early summer for spring crops.
Do not apply fertilizer to the garden in the fall. Winter rains will leach most fall-applied nutrients from the soil, wasting your time and money. The nutrients which are washed away can cause problems where they are not needed, polluting groundwater or causing algal blooms in ponds, streams, and rivers where they end up. Wait until spring and planting time to apply fertilizer. With a little fall preparation, spring planting will be easier than ever.
On Saturday, October 6 at the Ivy Transfer Station on Dick Woods Road the Rivanna Solid Waste Authority will be holding their Fall Household Hazardous Waste Collection from 9am 2pm. This opportunity is open to residents of Charlottesville, Albemarle, Nelson, and Fluvanna Counties. Materials accepted include paint, solvents, household cleaners, automotive fluids, lawn and garden chemicals, fuels, florescent tubes (including CFLs), smoke detectors, and cell phones. For more information check their web site at http://www.rivanna.org.
For more information about this and other landscape topics contact your local Virginia Cooperative Extension office. The local Virginia Cooperative Extension office numbers are Albemarle 872-4580, Fluvanna 591-1950, Greene 985-5236, Louisa 540-967-3422, and Nelson 263-4035.