Many field crops, ornamentals, greenhouse, and houseplants.
Spider mites, often called red spiders, are related to spiders and ticks and not insects. They are common plant pests that have four pairs of legs, no antennae, and a single, oval body section. Hot, dry weather is favorable for most spider mites and during the summer months they can complete a generation in 7 to 14 days. Besides red, the mites may be yellow or green with two dark spots on their bodies. They are about 1/50-inch in length. Probably the most common mite problem is due to the two-spotted mite.
Two-spotted mites cause chlorotic stippling of leaves giving the appearance that a fine tan to yellow sand has been sprinkled on the foliage. As populations increase, webbing is often spun over foliage and flowers. These mites are most likely to be found on the underside of leaves and in the flowers. The mites' piercing-sucking mouth parts cause curling of leaflets from outside inward by creating small depressions in young leaves. Damaged flower buds sometimes will not open or open only to be distorted. They spin tiny webs between the leaves and stems of a plant and suck juices from leaves, stems and buds. Symptoms of injury include flecking, discoloration (bronzing) and scorching of leaves. Injury can lead to leaf loss and plant death. On tomatoes greasy yellow to bronze-colored leaves are a sure sign of the tomato russet mite. Early detection is important. The mites can be detected by placing a piece of paper underneath the plant and shaking the plant over the paper. The mites can then be seen on the paper.
Controls include cultural practices - syringing with water, biological practices - using predators, and chemical controls - horticultural oils and miticides.