Texas Citrus Mite

Texas citrus mite is a sporadic pest of citrus in the inland valleys of California. Adult mites are tan-to-brownish green with dark green to black spots on the upper side of the body. Males are more slender than females and have much longer legs. Females have a more round-to-oval shape and are somewhat flatter than citrus red or Yuma spider mite. All stages of mites, including eggs, tend to be located along the midrib and lateral veins. Eggs are somewhat flat and disklike, are not a uniform color, and range from yellow when laid to a reddish brown before hatching.

Numbers of this mite decrease in summer but increase from September through December. When weather becomes cold and wet, which usually equates to the first overnight period of dense Valley fog, numbers decrease again. In the San Joaquin Valley, low numbers of Texas citrus mite can sometimes be found in spring, especially following insecticides such as formetanate hydrochloride (Carzol) that disrupt biological control.

Texas citrus mite feeds primarily on leaves and can cause significant stippling and leaf drop; significant leaf drop can lead to fruit drop. In the San Joaquin Valley damage is usually limited to early harvested navels where a combination of warm temperatures in fall and deficit irrigation (used to induce increases in sugar levels) allow mites to thrive. Damage often begins in the tops of trees and progresses downward as harvest approaches. Leaf drop from Texas citrus mite is unique because the leaf blade falls to the ground while the petiole remains in the tree. Leaf drop can result in sunburning of fruit, dropped fruit, and reduced photosynthesis.

In the San Joaquin Valley watch for Texas citrus mite in fall on early harvested navels or in spring following applications of broad-spectrum insecticides. Apply a pesticide if small amounts of defoliation begin to occur in the outer canopy at the top of trees and cold, wet weather is not anticipated for a period of weeks. Miticides are very effective against Texas citrus mite.

Texas citrus mite is naturally controlled by predators of other mites such as the sixspotted thrips (Scolothrips sexmaculatus), the spider mite destroyer (Stethorus picipes), minute pirate bugs (Orius spp.) and a predatory mite, (Euseius tularensis).

Adequate irrigation and dust control will reduce the damage caused by Texas citrus mite.

Use cultural and biological controls and certain petroleum oil sprays on organically managed citrus.

In the San Joaquin Valley, check for Texas citrus mite during spring if broad-spectrum insecticides such as formetanate hydrochloride (Carzol) have been used. Apply a pesticide if significant amounts of leaf drop occur.

In fall look for Texas citrus mite from September through December on trees that bear early harvested fruit, especially navels. Apply a pesticide if leaves in the outer canopy at the tops of trees begin to defoliate, and cold weather is not anticipated for a period of several weeks. Pesticides are not needed if defoliation is limited to the leaves on the extremities of the fall flush that will naturally freeze or be pruned off during winter.

No official treatment thresholds exist. Texas citrus mite is highly susceptible to all miticides labeled for control of citrus red mite and can be controlled with relatively low volumes of water because of its tendency to be located on newer leaves in the outer tree canopy.