Spider mites

Because spider mites like hot and dry weather, populations continue to wreak havoc on our garden crops. Tomatoes, in particular, seem to be bearing the brunt of spider mite pressure this year.

From a distance, damage shows up as leaves that turn from green to off green to brown. A closer look will reveal stippling on the upper surface of the leaves as well as some fine webbing on the underside of the leaves. Because of their very small size, they are difficult to see, particularly due to their habit of feeding on the underside of leaves. If mites are suspected, hold a sheet of white paper beneath a leaf and tap the leaf. Mites will be dislodged and can be seen as tiny specks on the paper that move about.

Spider mites are arthropods, not insects, so challenge is sometimes more difficult than with other garden insects. A high pressure directed spray of water can help, but it will definitely take a strong jet of water to dislodge them.

Any sprays that are used need to be directed at the underside of the leaves, meaning it needs to originate from below the plant in most cases. You may want to consider use of a specialized spray wand or other device to help get good coverage of the underside of the leaves.

A single application will not be enough. Spray three times spaced three to four days apart. Horticultural oils and insecticidal soaps (Safers, for example) can also be helpful. Spray early in the morning when temperatures are cooler and plants have rehydrated.