Pest Library

Ants – There are more than 12,400 species of ants throughout the world. In California, there are about 270 species, but fewer than a dozen are important pests. Ants are among the most prevalent pests in households. Ants also invade restaurants, hospitals, offices, warehouses, and other buildings where they can find food and water. Ants usually nest in soil; nest sites vary with species but are often found next to buildings, along sidewalks, or in close proximity to food sources such as trees or plants that harbor honeydew-producing insects.

Ants also construct nests under boards, stones, tree stumps, or plants and sometimes under buildings or other protected places. Ants often enter buildings seeking food and water, warmth and shelter, or refuge from dry, hot weather or flooded conditions. They may appear suddenly in buildings if other food sources become unavailable or weather conditions change. The most common ant in and around the house and garden in California is the Argentine ant.

Argentine Ant – The argentine ant is light to dark brown measuring 1/10″. This ant is readily adaptable and can nest in a great variety of situations. Colonies are massive, and may contain hundreds of queens. Their nests are usually located in moist soil, along sidewalks, or beneath boards. They often invade residential and commercial buildings in search of food and/or shelter. They travel in trails and forage day and night. The ant can eat almost anything but prefers sweets. It has no natural enemy in the United States.

Red Imported Fire Ant – Are not commonly found indoors, however they can be found anywhere outside including shrub beds, middle of the lawn, inside potted plants and along sidewalks and driveways. They have a painful stinging bite which can cause anaphylaxis, which can be life threatening to elderly people and infants. A Fire Ant mound has multiple entry and exit ways. Do not disturb the mound because it will spread the colony.

American Cockroach – The American Cockroach is among the largest of all cockroaches with adults ranging between 1″- 1 1/2″ They are reddish brown and have a yellowish margin on the body region behind the head. American cockroaches generally live in moist areas, but can survive in dry areas if they have access to water. They prefer warm temperatures and do not tolerate cold temperatures well. In residential areas, these cockroaches live in basements and sewers, and may move outdoors into yards during warm weather. Like all cockroaches, they are omnivorous and will eat virtually anything.

German Cockroach – The German Cockroach is about 0.63″ inches in length and can be easily recognized by the two dark, longitudinal stripes on the “shield” at the front of the body under which the head is located. The German cockroach is the most prolific breeder among all cockroaches and like all cockroaches; it is omnivorous and will eat virtually anything. This pest will first locate itself in bathrooms and the kitchen, as close as possible to food and moisture sources and then spread throughout a home or building as the population grows. During its life it will spend about 80 percent of its time resting in cracks and voids.

Black Widow – The black widow (female) is shiny black with a bright red hourglass shaped marking on the underside of the abdomen. The female hangs upside down in the web such that the red hourglass faces up. This spider is present in all 50 states and is found in Canada and South America. The silk strands of its web are considerably heavier and stronger than those of other spider species. Black widows are classified as dangerous spiders because their bite can cause severe cramping and pain throughout the body. Very young children, the elderly and very ill persons are most at risk for severe reactions to bites.

Brown Recluse – Yellowish-tan to dark brown in color. It has dark brown legs covered with short, dark hairs. The brown recluse is identified by 3 pairs of eyes arranged in a semicircle on the front of the head and a violin-shaped marking behind the eyes. The neck of the violin points away from the head toward the abdomen. They are most active at night and prefer dark, undisturbed areas. The brown recluse is not aggressive but will bite if disturbed. Bites are rarely fatal but do require immediate attention by a physician as they cause ulcerating sores. Left untreated, such bites often become infected and significant tissue necrosis can occur.

House Spider – Of the many species of identified spider species, house spiders are typically the most frequently found in our dwelling places. Although their presence is unnerving, house spiders are not necessarily lethal to humans. Small, controlled populations can even be useful, as they eat other unwanted pests. Several species are considered house spiders. Some of the more prevalent house spider species include the common house spider, the domestic house spider, the aggressive house spider and the brown house spider.

Wolf Spider – Are similar in appearance to the Brown Recluse Spider. They scurry along the ground and walls and are avid daytime hunters. Wolf Spiders include several different sub species and can range in size from ¼” to the as large as a human hand. A Wolf Spider is poisonous but at a low toxicity. Their bite can be painful and cause irritation and swelling of the skin.

Pillbugs – Pillbugs range in size from 1/4 to 1/2 inch long and are dark brown to slate gray. Their oval, segmented bodies are convex above but flat or concave underneath. They possess seven pairs of legs and two pairs of antennae Sowbugs also have two tail-like appendages. Pillbugs can roll up into a tight ball when disturbed, for which they are sometimes called “roly-polys”.Pillbugs live in moist environments outdoors but occasionally end up in buildings. Although they sometimes enter in large numbers, they do not bite, sting, or transmit diseases, nor do they infest food, clothing or wood. They are simply a nuisance by their presence.

Silverfish – A silverfish is a small, wingless insect whose name is derived from the animal’s silvery light grey and blue color, combined with the fish-like appearance of its movements.Silverfish consume all kinds of matter including glue, book bindings, some paints, paper, photos, sugar, coffee, hair, carpet, clothing and dandruff. Other substances that may be eaten include cotton, linen, silk, synthetic fibers and dead insects. During famine, a silverfish may even attack leatherware and can live for a year or more without eating.Silverfish are considered a household pest, because of their consumption and destruction of property. Although they contaminate food and other types of damage, they do not transmit disease.

Earwigs – The adult earwig is readily identified by a pair of prominent appendages that resemble forceps at the tail end of its body. Used for defense, the forceps are somewhat curved in the male but straighter in the female. The adult body is about 3/4 inch long and reddish brown. Most species have wings under short, hard wing covers, but they seldom fly. Immature earwigs look like adults except they are smaller and lack wings.Earwigs feed most actively at night and seek out dark, cool, moist places to hide during the day. Common hiding places are under loose clods of soil, boards, or dense growth of vines or weeds or even within fruit damaged by other pests such as snails, birds, or cutworms.To control earwigs, complement your pest service program by removing refuge sites for earwigs, such as ivy, weeds, piles of rubbish, and leaves. Never allow heavy ground cover such as ivy to grow near vegetable gardens. Watch out for mulches; they often harbor earwigs. Natural enemies including toads, birds, and other predators may play an important role in some gardens. Chickens and ducks will consume many earwigs.

Centipede – Centipedes can easily be distinguished from millipedes by counting the number of pairs of legs arising from most body segments: millipedes have two pairs, while centipedes bear one pair per segment, with the first pair of legs being modified into fangs. Centipedes are generally flattened and have a pair of well developed antennae on the head. Some centipedes, such as thehouse centipede, have long legs and are capable of running rapidly. The largest centipedes may grow to be about 6 inches long.Centipedes prefer to live in moist habitats and during the day occur underneath rocks, logs and other objects in contact with the ground. They are active at night. Centipedes feed on insects and spiders. They kill by grasping prey with their powerful fangs and injecting venom.

Millipede – Common North American species are brownish, one to 1 – 1/2 inches long; segmented, with 2 pairs of legs per segment. Millipedes normally live outdoors in damp places. Around homes they live in flowerbeds and gardens.Millipedes are generally found under mulch, piles of dead leaves, or under piles of grass clipping. Millipedes also live under structures like dog houses and storage sheds. Millipedes thrive in places where the soil stays damp year round. They eat dead leaves and decaying wood that they find.

Crickets – House Crickets measure between 3/4 and 7/8-inch in length. They are light, yellowish-brown in color and exhibit three dark bands atop their heads. Field crickets are brown or black in color and can grow to measure more than one inch in length. Ground crickets are brown and much smaller than other common cricket species. Crickets dwell beneath rocks and logs and are nocturnal in nature. They are omnivorous scavengers and renew soil minerals by breaking down plant materials.

Roof Rats – Are smaller and more slender in appearance than Norway Rats. Adults weigh 5-9 oz. and up to 8” in length. They have a slender body. Their snout is pointed, ears are large and their tail is longer than their body. With adequate food and shelter, Roof Rats will live in close proximity to humans and prefer living in attics, ceilings and walls. They often chew on wires, which leads to outages and fires. They produce a strong musty odor. They carry a variety of diseases and pose serious health risks.

Norway Rats – The Norway rat has a stocky body measuring 10″-12″ (without the tail). They are much larger than mice, and can weigh as much as one pound. It has a blunt nose and its scaly tail is shorter than the head and body combined. Rats contaminate food and cause extensive damage to buildings and equipment in houses, granaries, restaurants and other areas they inhabit. Rats are able to gnaw through wood, electrical wires, and even unfinished concrete. Rats are excellent climbers and need a hole only as big as a quarter to gain entry into a home. Rats are known to be a source of numerous diseases affecting man, such as the Plague and Murine Typhus. Rats will eat nearly any type of food, but they prefer high-quality foods such as meat and fresh grain. Rats require 1/2 to 1 fluid ounce of water daily when feeding on dry food. Rats have keen taste, hearing and sense of smell.

House Mouse – The adult house mouse is slender and about one to two inches in length, excluding its tail. It has large ears, a pointed nose and small eyes. The fur color is usually a light grey or brown, but can be darker shades. They are good climbers, swimmers, and jumpers. They rarely travel farther than 40-50 feet from their homes.Mice will eat almost anything but prefer cereal grains, seeds, or sweet material. They require very little water, obtaining most of their water needs from their food. If there are good living conditions (food, water, and shelter), they can multiply rapidly. They sexually mature in two months, producing about eight litters in a one year life time. Each litter has four to seven pups. They make their nest from soft material like paper, insulation, or furniture stuffing. These nests can be found in many places including walls, ceiling voids, storage boxes, drawers, under major appliances, or within the upholstery of furniture. Outside nests are found in debris or in ground burrows.

Wasps – There are thousands of different species of wasps with the most familiar being the paper wasps, yellow jackets and hornets. Despite the fear they sometimes evoke, wasps are extremely beneficial to humans. Nearly every pest insect on Earth is preyed upon by a wasp species for food or as a host for its larvae. Wasps are distinguishable from bees by their pointed lower abdomens and the narrow “waist,” called a petiole that separates the abdomen from the thorax.

Snails – Snails and slugs are among the most bothersome pests in many gardens and landscapes. Thebrown garden snail is the most common snail causing problems in California gardensBoth snails and slugs are members of the mollusk phylum and are similar in structure and biology, except slugs lack the snail’s external, spiral shell. These mollusks move by gliding along on a muscular “foot.” This muscle constantly secretes mucus, which facilitates their movement and later dries to form the silvery “slime trail” that signals the presence of either pest.Snails and slugs are most active at night and on cloudy or foggy days. On sunny days they seek hiding placesout of the heat and bright light. Often the only clues to their presence are their silvery trails and plant damage. In areas with mild winters, such as southern coastal locations, snails and slugs can be active throughout the year.

Bed bugs – Bedbugs are small, oval, brownish insects that live on the blood of animals or humans. Adult bedbugs have flat bodies about the size of an apple seed. After feeding, however, their bodies swell and are a reddish color.Bedbugs do not fly, but they can move quickly over floors, walls, and ceilings. In her lifetime, female bedbugs may lay hundreds of eggs, each of which is about the size of a speck of dust.Bedbugs can enter your home through luggage, clothing, used beds and couches, as well as other items. Their flat bodies make it possible for them to fit into tiny spaces, about the width of a credit card. Bedbugs do not have nests, but tend to live in groups out of sight. Their first hiding places are usually in mattresses, box springs, bed frames, and headboards where they have easy access to people to bite during the night.Over time, however, they may scatter through the bedroom, moving into any crevice or other protected location. They may also spread to nearby rooms.Because bedbugs live solely on blood, having them in your home is not a sign of dirtiness. You are as likely to find them in immaculate homes and hotel rooms as in filthy ones.