When thinking of spiders, you’re probably picturing a brown recluse, black widow or even a hairy tarantula. Gardeners, however, are familiar with another type of spider – the spider mite – which can wreak havoc on your garden.
We have several more weeks in which spider mites typically are active. They thrive in hot, dry weather and can become a severe problem.
While your typical spiders are fairly large and easy to see, spider mites are quite small and barely visible to the naked eye. Often referred to as a red spider, the spider mite begins its lifecycle with just six legs, but soon gains two more to become more spider-like in all other stages of their lifecycle. Spider mites are not insects, but instead are related to spiders and ticks.
Very few plants are completely immune to spider mites, but tomatoes and marigolds are just a couple of their favorites.
Oklahoma features several different species of the spider mite. While many of them are reddish in color, others are more brownish or pale greenish. Another distinguishing mark is two or more darker spots on the back.
Some species do follow along with traditional spiders by spinning a fine, irregular web over the infested parts of plants, but other species spin very little or no webbing. Webbing may be present around colonies on leaves, stems and fruit.
With a light infestation, gardeners may start noticing a pattern of small, pale spots on plant leaves. A heavier infestation has occurred when the spots begin to run together, causing the death of a leaf or needle or reduced fruit production. Unfortunately, this type of damage often is the only sign of an infestation.
So, how do you control spider mites? Select crops that are well adapted to the local climate and soil. In addition, pests can be kept in check by maintaining a healthy crop through cultural practices such as proper fertilizing and irrigation. Finally, preventing small infestations from becoming larger, more destructive infestations is ideal. At first signs of an infestation, a strong stream of water can often be used to wash the mites off of the plants and keep the infestation to a manageable level. Regular washing can keep spider mites under control on most landscape plants. This technique also helps conserve natural predators.
Of course, spider mite control also can be achieved with applications of insecticidal soaps or horticultural oils. Make sure you get good coverage on the plants, especially the feeding sites on the undersurface of leaves. Several applications may be necessary. Be sure to select a product listed to control spider mites and be sure to read and follow all label directions.
For more information about spider mite control, contact your Oklahoma State University Cooperative Extension county office.