Brown Wheat Mite: Appearance, Territory, Damage, and Life Cycle

Latin Name: Petrobia Latens Appearance: Petrobia latens (Müller), a prevalent pest of dryland wheat in western Kansas, can be a problem as far east as Manhattan during dry years. It causes stippling of the wheat leaves by damaging plant cells as it eats. Brown wheat mites feast on the ends of the leaves, causing them to dry up and perish. Fields that have been heavily infected seem burnt and wilted. Hosts Plants: Plants that host Brown wheat mite damage has been documented on a wide range of cultivated plants, including alfalfa, clover, wheat, and barley crops, as well as vegetable crops and Kentucky bluegrass turf. Territory: The brown wheat mite is more common in the dry climes of Colorado and Wyoming, although it may become common in western Nebraska under the correct conditions. Damage Insect Cause: The mites spend the night in the soil and among the leaves near the earth, then migrate up during the day to feed on the leaves. Stippling or yellowing of the leaves is caused by feeding, especially at the leaf tips. Extensive damage will result in plants that are bronzed or brown and seem drought-stressed. Brown wheat mite feeding will have the greatest impact when plants are challenged by drought. Brown wheat mite infection is more common in continuous winter wheat or when volunteer wheat was present the previous spring. These conditions can lead to significant numbers of over-summering white eggs hatching and infesting the fresh crop in the fall. To limit the possibility of huge mite populations, control volunteer wheat and prevent continuous winter wheat. Life History and Habits: Brown wheat mites have a brief lifespan and can have several generations in the winter. In the fall, one or two generations may form, and in the spring, another two or three generations may form. During the day, brown wheat mites feed, with activity on the plants peaked about midday. They don’t make webbing, though. When startled, they dash over the leaf’s surface quickly or fall to the ground. They scurry into the ground at night. Brown wheat mite activity is at its height in late autumn and early spring, with numbers typically peaking around mid-April. Because all adults are female and may lay 70 to 90 winter eggs in three weeks, the potential for an outbreak is great. Females begin depositing little, white overwintering eggs in the soil at the base of afflicted plants later in the spring.