Return to Insect Pests

Two-spotted spider mite (Tetranychus urticae) females are yellow to dark green, with two to four dark dorsal spots. At 1⁄60 of an inch, they are almost microscopic. Males are smaller and have more pointed abdomens. The tiny, spherical eggs are laid on the underside of leaves, often under the webbing produced by the mites. Mites attacking cucurbits are more common in hot, dry weather, and infestations usually begin around the field margins. Under optimum conditions of high temperature and low humidity, the life cycle may be completed in seven days; females can lay 200 eggs. Initial damage appears as tiny, light spots in the leaves (stippling), which over time will turn brown, with the leaves dying prematurely.

Two-spotted spider mite.

(Photo: Ric Bessin, University of Kentucky)

Two-spotted spider mite damage to melon leaf.

(Photo: Timothy Coolong, University of Kentucky)

Management:

• Natural enemies of mites can keep their populations low, but the use of insecticides to control insect pests severely reduces the numbers of these beneficial insects.
• Apply insecticides only as needed rather than at regularly scheduled intervals.
• Destroy weeds adjacent to and in fields during the fall or early spring, and carefully manage weeds around fields during the season. Spraying or mowing of weeds after growth may increase the movement of mites to cultivated plants.
• Irrigation with an overhead sprinkler may provide some short-term relief of mite infestations.
• Use miticides only when needed. Because mite populations are often localized, spot spraying may be effective. When spraying only a portion of the field, expand the spray zone to include an area 100 to 200 feet beyond the mite-infested area.

Return to Insect Pests