|
|
Garden and Landscape Aphid Control
- Aphids can do a lot more damage than you think! -
|
Summary: Aphids are small insects that suck plant juices and can severely stunt or even kill their hosts. Early detection and control with insecticidal soap are the keys to managing aphids in gardens and landscapes.
Jack DeAngelis, PhD
OSU Ext. Entomologist (ret.)
|
|
|
|
 This page will help you get rid of aphids from your garden, house and landscape plants. Aphids may be the most important of all garden and landscape pests.
Aphids occur on nearly all plants, their populations can build quickly and their effects can be severe. Aphids feed by inserting tube-like mouthparts into the plant's vascular system and withdrawing plant sap. Plant sap is a complex mixture of water, sugar and a small amount of protein. To get the protein they need, aphids must take in a lot more sugar than they can use - excess sugar is expelled through the body as a concentrated sugar solution called honeydew.
While they feed on plant sap, aphids may inject their host plant with growth regulators that deform plant tissue. Evidence for these toxins can often be seen as twisted growth and dead tissue above where aphids are feeding. Aphids can be found on both above and below-ground plant parts. See the Guides below for more about aphid biology.
common misspellings and misnomers for aphids: plantlice, plant lice, greenfly, green bug, aphis
|
 |
| soybean aphids (yellow) on soybean leaf; photo by USDA/ARS |
|
|
|
|
|
|
Books about aphids
Unfortunately, books about aphids tend to be highly technical with much more detail than most gardeners need. This American Horticultural Society reference is a good compromise for both beginning and advanced gardeners. In one volume you'll find solid information about both pests, including aphids, and diseases.
More Gardening Books
New Garden Titles for 2006 - '07
|
|
|
|
Aphid control in gardens
Aphids have a wide range of natural enemies. Predators like syrphid fly larvae, lady beetle adults and larvae, and lacewings as well as parasitic wasps, and others, are important in aphid control. The typical cycle is for an aphid colony to build rapidly in spring followed by a rapid decline in summer after the colony is discovered by a natural enemy. Sometimes more than one natural enemy will "work" a colony at the same time.
Aphids are important pests in gardens as well as in commercial agriculture. Accurate identification of pest species is both difficult and extremely important and therefore has gotten considerable research attention. The following reference book is an excellent resource if you need this level of detail - Aphids on the World's Crops: An Identification and Information Guide, 2nd Edition (2000) by R. L. Blackman, V. F. Eastop. (more information ).
For home gardeners the best chemical control is insecticidal soap. The guidelines for controlling aphids are the same as those for spider mites using overhead irrigation and insecticidal soap. The best physical control is the use of row covers early in the season where they are practical. Neem oil insecticide also is effective against aphids.
Row covers are made of a thin, strong, non-woven fabric that allows light, water and air to get in but excludes flying pests like aphids, leaf-feeding beetles and thrips. They work great in greenhouses and over garden rows. Place row covers, loosely, early in the season before aphids and other pests get started.
Some insecticidal soaps may be combined with a low toxicity insecticide like pyrethrum or neem. These work equally well. Gardens Alive! is a source of aphid control products and row covers or see the Tool Kit page for more suggestions.
|
 |
Use a hand lens to check for aphids and natural enemies.
|
|
 |
Row covers protect plants from aphids, spider mites and cucumber beetles. Also protect against heat and cold.
|
|
|
|
|
|
|
|
|
