Insect Pests

The topside of this bean leaf shows the characteristic stippling from the many tiny points where mites pierce the backside of the leaf to suck sap. - Clemson University USDA Cooperative Extension Slide Series, www.insectimages.org

Spider mite webs often stretch across leaves and stems. They are worst during dry weather and tend to subside in rainy weather. - Clemson University USDA Cooperative Extension Slide Series, www.insectimages.org

This close-up of the two-spotted spider mite shows adult mites, dark droppings that are often present, shed skins (white), and tiny, round, light yellow eggs that quickly hatch into new mites. - Whitney Cranshaw, Colorado State University, www.insectimages.org

The Banks Grass mite is a pest of corn in the West. This is the damage from its feeding. It does not make webs. - Whitney Cranshaw, Colorado State University, www.insectimages.org

Spider mites, also known as “red spiders”, are so small that you can barely see them. Often you do not know that they are present until the leaves begin yellowing and drying up as thousands of mites suck sap from the plant.

Often worst during mild, dry weather, spider mites make mealy cobwebs on the undersides of leaves that can stretch from one leaf to another, perhaps entirely covering new buds and plant shoots. The mites multiply rapidly, so it is crucial to control them immediately.

To control, use ultra-fine oil or insecticidal soap, covering the undersides of the leaves, shoots, and tops of the leaves thoroughly. You will probably need to spray two or three times because some always manage to survive under the cover of the web. Use a forceful enough spray to penetrate the web. For other products approved in your state, contact your local Extension office.

Mites have a way of finding your garden no matter what, but you can delay their entrance by cleaning up the garden at the end of the season.