Most people think of the desert as a vast wasteland, where nothing can survive. The reality is that the Sonoran Desert is a thriving wildlife community that, for the most part, has been undisturbed by man. Since a large number of insect, rodent and reptile species live in the desert and have evolved to survive in this environment with limited resources, human dwellings present a tremendous opportunity to them. The presence of these pests will vary based on a number of factors.


Landscaping and water have the greatest effect on pest populations. The seasons provide ranges in temperature and moisture. Each species has an optimal temperature range and a preferred moisture level. When the best conditions for any type of pest are present, activity, feeding and reproduction increase. As populations build in the desert, pests start looking for additional living space, food and other resources. A large structure provides some hiding places, increased moisture due to irrigation, warmth at night, shade in the daytime, and in many cases, increased food supply. This food can include a barbeque grill that has not been cleaned, dog food left by the family pet, spilled trash, bird feeders or even snacks left behind by the kids.

Seasonality also brings about changes in the length of the day. In many species, reductions in the length of daylight, together with a drop in temperature triggers a “hibernation” behavior causing large numbers of insects to migrate into structures.

Dooryard pests are “pests of opportunity,” also known as “occasional invaders,” and for the most part are harmless. Probably the most common of these pests, crickets, can invade the home in large numbers. If not addressed, they are capable of establishing in the home, reproducing in attics, crawlspaces and garages. The desert is home to several different types of cockroaches. The large American cockroaches that can be found under rocks and leaf litter, flourish around swimming pools and landscape mulch. During the rainy season, they get “flushed” out of their hiding places and scatter into homes. Desert cockroaches, smaller mottled roaches with wings, also can enter homes. Asian cockroaches, capable of flight, are attracted to lights at night and can be seen crawling on homes in the evening. Also attracted to light are, moths, crane flies, beetles, kissing bugs, ant and termite swarmers (flying ants and termites), earwigs, mayflies, lacewings and even a strange little insects called web spinners.

Often I am asked, “Why are moths and other insects attracted to light?” Lights don’t occur at ground level at night in nature. The closest thing is the moon. Night flying insects use the moon to orient themselves and navigate, never thinking they will actually get there. If a moth were to fly, attempting to keep a light bulb “moon” over its left shoulder, for instance, it would fly in circles around the bulb. The slightest change in angle would send it spiraling away or toward the light bulb until: CRASH! The moth slams into its moon! Of course, insects are not adapted to land on their moon and without a mechanism to deal with the situation. They are over stimulated, sitting with their wings vibrating. Come morning, they are exhausted, fall to the floor and look for the nearest hiding place, under your door. In the morning, you open the door and they are in!

Spiders, as a group, also make up a large percentage of the pests you might find in the home. Attracted to the home by the insects around the light, the cockroaches and the crickets, they enter the home through windows and doors or as hitchhikers on boxes, houseplants or even the home’s occupants. Though it is true, all spiders have venom, most are harmless to humans and many can’t even penetrate the skin. Another way spiders get into homes is by ballooning. Have you ever walked out to your car and get a spider web strand across the face? A baby spider caused this! Shortly after emerging from an egg sack, baby spiders climb to a high point and toss strands of spider silk into the air. Even a slight breeze will pick up this strand, carrying the spiderlet to its new home—your hair, your car’s windshield, or if your door is open, your living room.

A dooryard pest that causes a great deal of anxiety is earwigs. Sometimes called “pincer bugs” these completely harmless insects have a pair of pincers at the rear end. They also have fully developed wings folded into two packets on their back, enabling them to fly to homes from the desert. Solpugids, also known as sun spiders, are large tailless scorpions with their pincers mounted directly to the front of their faces. Completely harmless, these animals look ferocious. With even bigger pincers, large Palo Verde beetles, over three inches in length, are attracted to lights and can be found milling by front doors in the evening and mornings. These beetles are also harmless but can be entertaining. Placing a business card or credit card in its jaws, they will walk around, carrying it like a billboard. Sometimes, dooryard pests can be alarming due to their large numbers. Boxelder bugs will enter homes in large numbers in September to overwinter, migrating from the landscaping. Ladybugs can enter homes for the same purpose and can be so numerous that they can be removed with a shovel.

Not all dooryard pests are harmless. Giant desert centipedes have a toxic bite. They also have small hooks at the tips of their feet. These hooks, though not venomous, often leave rows of irritating welts over the skin of the usually sleeping victims. More than six inches in length, these pests can squeeze through a crack ¼ inch wide. Kissing bugs are attracted to homes by lights at night from packrat nests in the desert. Though the bite has no venom, it can produce an extreme allergic reaction in its victim. This reaction can be hazardous because kissing bugs tend to bite on the face, giving them their name. Scorpions are also occasional invaders and the toxicity of their sting varies by species, with the smaller varieties being more toxic than the large ones. The web less, hunting brown spider (sometimes erroneously called the brown recluse) can be extremely toxic, as can the black widow spider. On occasion, ants will trail in to a home through a window, door or crack from the outside. Though many are harmless, some can have a vicious sting that can be serious by virtue of the numbers of stings. Even individual wasps can be dooryard pests. Queen paper wasps will sometimes over winter in a home tucked in a corner or the folds of a drape. In the spring, they emerge, trying to find a way out of the home.

Making your home and landscaping less attractive to these pests will reduce your chances of being harassed by them. Prevent entry by ensuring door and window seals are in place. Routine inspections by a pest control professional will help ensure that these problems are anticipated and prevented, keeping your home, family and pets safe from dooryard pest intrusion.

Call us today to find solutions to your dooryard pest problems. In Tucson, call 886-4146. Statewide, call (520) 886-4146.

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