Learn More About Nuisance Insects

Need to identify the species of your unwelcome visitor? Learn more about the specific types of invasive bugs in our nuisance insect pest library.

Nuisance Insect Pest Library Menu:

> Flies

> Springtails

> Sow Bugs & Pill Bugs

> Spiders

> Cockroaches & Water Bugs

Flies

Flies rank among the most common and widespread pest insects in the United States. Numerous species invade homes and businesses, including house flies, blow flies, drain flies, and fruit flies. Because flies seek out food waste, moisture, decaying organic matter, and unsanitary conditions, they become a frequent nuisance in both residential and commercial environments.

Flies reproduce rapidly. Females lay hundreds of eggs throughout their lifespan, typically depositing them in garbage, animal waste, drains, or other moist organic materials. Larvae (maggots) develop quickly, which allows populations to grow in a short period of time.

Beyond being a nuisance, flies pose a health risk because they spread bacteria and pathogens by contaminating food and surfaces. Common signs of a fly problem include frequent sightings, buzzing activity near food areas, larvae in trash or drains, and dark stains on walls or windows.

Effective fly control focuses on sanitation, exclusion, and moisture management. Removing food sources, sealing entry points, maintaining clean drains, and disposing of waste properly are all essential prevention steps. However, persistent or large infestations often require professional treatment to locate breeding sites and apply targeted solutions.

Springtails

Springtails thrive in damp environments and most commonly appear outdoors under loose soil, debris, mulch, and potted plants, where they feed on fungi, algae, and rotting vegetation. Inside homes, they gravitate toward moisture-rich areas such as drains, insulation, damp basements, and window moldings, feeding on cork, insulation, and indoor plant matter.

Springtails are extremely small — growing less than 1/12 of an inch — and appear white or grey in color. They do not fly. Instead, most springtails use two fork-like appendages to launch themselves into the air when disturbed. Although they cause little direct damage, springtails become a pest problem because they appear in large numbers and are difficult to eliminate without addressing the underlying moisture issue.

Sow Bugs and Pill Bugs

Sow bugs and pill bugs are more closely related to shrimp and crawfish than to true insects — they breathe through gills and require moist environments to survive. People commonly refer to them as rollie-pollies or doodle bugs. They feed on dead leaves and decaying vegetation and prefer outdoor environments, but they will move indoors wherever conditions are dark and damp. Inside homes, they commonly appear in crawl spaces, potted plants, and basements.

There are two distinct types worth knowing. When disturbed, the common pill bug rolls into a tight ball for protection — a defense mechanism made possible by the absence of small appendages at the front of its body. The dooryard sow bug looks nearly identical but has small appendages at the front of the body that prevent it from rolling into a ball. Additionally, the dooryard sow bug has two small tail-like appendages at the abdomen that further distinguish it from the pill bug.

As a general rule, a large population of sow bugs or pill bugs inside a home indicates an even larger population living just outside. Addressing exterior moisture and entry points is essential for long-term control.

Spiders

Arizona Brown Recluse

The Arizona brown spider is a recluse species found throughout Arizona. It has three sets of eyes, eight long legs, and grows to between 1/4 and 1/2 inch in length. Its yellowish-brown body and distinctive violin-shaped marking on the head make it identifiable — a feature it uses to deter predators.

Key facts about the Arizona brown spider:

It can survive 6 to 12 months without food.
Its venom produces a toxic reaction that can cause serious skin damage. Anyone bitten by a recluse spider should consult a doctor immediately.
During the day, it hides in dark, undisturbed areas. At night, it becomes highly active and hunts small insects, either catching them in webs or pursuing them directly.

Tarantula

Tarantulas are large, hairy spiders that inhabit the dry desert regions of the world, including Arizona. Despite their intimidating appearance, their venom is actually weaker than that of the average bee.

Key facts about tarantulas:

Their bodies can reach up to 4 3/4 inches in length, with a leg span of up to 11 inches.
Rather than spinning webs, tarantulas actively hunt their prey, injecting venom to paralyze it before feeding. After a meal, they may go without eating for up to a month.
Tarantulas have very few natural enemies. However, the Pepsis wasp is a notable exception — it paralyzes the tarantula with venom, lays its eggs on the living spider, and the hatching larvae feed on it from the outside in.

Sun Spider

Sun spiders are unusual arachnids found throughout the United States, particularly in hot, arid regions like Arizona. Several characteristics set them apart from other spiders.

Key facts about sun spiders:

They grow to between 1 and 3 inches in length and are yellowish or tan in color.
Instead of spinning webs, sun spiders use large, sticky leg-like pedipalps on either side of the jaw to capture prey. These pedipalps give them the appearance of having five sets of legs rather than four.
Sun spiders are fast movers and skilled diggers, spending most of their time underground and becoming most active in hot, arid desert conditions.
They eat insects and occasionally small lizards. Although they may bite when handled, they are not venomous.

Black Widow

Black widows are one of the most recognized spiders in the United States and appear throughout Arizona. Females are easily identified by their shiny black body and the distinctive red hourglass marking on the underside of the abdomen. The female’s abdomen measures approximately 1/4 to 1/2 inch in diameter. Males are significantly smaller and lighter in color, with pale streaks across the abdomen.

Black widows build irregular webs made of dense fibers, typically under boards, stones, and foundation slabs. They rarely enter homes directly but frequently inhabit the areas immediately surrounding them.

Their bite demands serious attention. Black widow venom is reported to be 15 times more potent than rattlesnake venom and directly affects the nervous system. In humans, a bite can produce muscle aches, nausea, and paralysis of the diaphragm that makes breathing difficult. Anyone bitten

Cockroaches and Water Bugs

Cockroaches are among the most persistent household pests in the United States, particularly in warm climates like Arizona. Several species invade homes and businesses, including German, American, and Oriental cockroaches. The insects people commonly call “water bugs” are typically large cockroach species — most often American or Oriental cockroaches.

Cockroaches prefer dark, warm, and moist environments. They commonly hide in kitchens, bathrooms, drains, wall voids, and basements. Because they are nocturnal and stay hidden during the day, infestations often grow undetected until populations become significant. Roaches reproduce quickly — females produce egg cases that each contain dozens of eggs.

Beyond being unsightly, cockroaches pose a genuine health risk. They contaminate food and surfaces and spread bacteria and allergens that can trigger asthma and allergic reactions. Common signs of infestation include live or dead roaches, droppings resembling black pepper or coffee grounds, discarded egg cases, and a musty odor in affected areas.

Effective cockroach control requires a combination of sanitation, moisture reduction, and exclusion. Sealing cracks, repairing leaks, storing food properly, and cleaning regularly all help reduce attractants. Nevertheless, because roaches reproduce rapidly and hide in hard-to-reach areas, professional pest control is typically necessary for complete, long-term elimination.