Bugs and spiders in Arizona

What to watch for in Arizona

The Arizona bark scorpion is the most venomous scorpion in the US, and its sting is very painful and can be dangerous for young children and older adults. Call Poison Help (1-800-222-1222) right away after a sting. It is active most of the year in low desert areas, especially on warm nights above about 70°F. The western black widow is the other one to respect; an adult female's bite can cause severe muscle pain and cramps, so get medical advice.

In Arizona the brown dog tick is the main carrier of Rocky Mountain spotted fever, according to the state health department, and it can breed indoors where dogs live. The western blacklegged tick and Rocky Mountain wood tick are limited to the places noted above. Brown widow and American dog tick records exist, but neither is known to live in the state.

Through the year

Spring

Pill bugs show up indoors after long rainy periods, and western black widows become most active as late spring arrives.

Summer

Bark scorpions are active on warm nights above about 70°F, European paper wasps work around the outside of the house, and yellow fever mosquitoes bite through the warm months.

Fall

Boxelder bugs move in from late August, western conifer seed bugs follow in September and October, and Asian lady beetles arrive in October and November.

Winter

Bark scorpions are least active from November through March, firebrats gather near furnaces and heating pipes, and Indianmeal moths are found indoors all year.