Tiny creatures often appear around homes, especially on outdoor surfaces like patios and foundations. These small, reddish-brown arachnids are commonly known as concrete mites, a term often used to describe clover mites (Bryobia praetiosa). Their sudden appearance can lead to questions about whether they pose any threat to humans or property.
Understanding Concrete Mites
Concrete mites are minute arachnids, close relatives of spiders and ticks. Adults are smaller than a pinhead, measuring about 0.75 millimeters in length. They have an oval-shaped body that can range in color from reddish-brown to olive or greenish-brown. A distinctive feature is their unusually long front pair of legs, often mistaken for antennae.
These mites are frequently found in outdoor environments, particularly in areas with lush vegetation like lawns, gardens, and around building foundations. They feed by sucking plant sap from various plants, including clover, grasses, and ornamental flowers. Clover mites do not consume human tissue or blood, nor do they feed on structural materials.
Are Concrete Mites Harmful to Humans?
They are not considered harmful to humans or pets. They do not bite or sting, nor are they known to transmit diseases. Their presence is primarily a nuisance, particularly when they invade homes in large numbers. This often occurs during seasonal changes, such as in spring or fall, when outdoor conditions become less favorable, prompting them to seek shelter indoors.
Once inside, these mites do not infest food, clothing, or furniture, and they do not cause structural damage to buildings. They do not survive long indoors due to a lack of their preferred plant food and suitable environmental conditions. A common concern arises from the reddish stains they can leave behind when crushed. This red mark is due to the mites’ body fluids and pigments, not blood, and while it can stain light-colored surfaces, it poses no health risk upon contact with skin.
Identification and Management
Identifying clover mites involves observing their characteristic long front legs, which appear like antennae. Unlike spider mites, which can produce webbing, clover mites do not. When crushed, clover mites leave a distinct red stain, a key distinguishing feature.
Preventing clover mites from entering homes involves several non-chemical approaches. Creating a plant-free buffer zone, 18 to 24 inches wide, around the foundation can deter them, especially if covered with materials like pea gravel or mulch that mites find difficult to traverse. Sealing cracks and crevices around windows, doors, and the foundation also helps block entry points. Maintaining outdoor vegetation by trimming shrubs and plants away from the house exterior and avoiding over-fertilization of lawns can further reduce their populations near the home.
Should concrete mites find their way indoors, simple removal methods are effective. Vacuuming them up is recommended to avoid crushing them and causing stains. A damp cloth or sponge can also be used to wipe them away. For persistent issues, contacting a pest management professional can provide further guidance on managing larger infestations.