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Monsoon season means rise in pest, reptile activity in Arizona

(Public Domain Photo)

PHOENIX — As the monsoon season hits its full stride in Arizona, residents should expect to have some unexpected — or downright creepy — visitors in their homes.

The increase in humidity and the heavy rainfall tends to be the impetus insects, rodents and reptiles need to come out of hiding.

Though it happens every year, the sudden influx of critters can be annoying, damaging or, at some points, dangerous.

Insect explosion

“All insects need a little bit of humidity — that kind of sets them off and gets them going when it comes to reproduction,” Sage Garvey, operations director at Burns Pest Elimination, said.

“Sometimes that’s done around your house with your irrigation system, pool, and or leaks around your house.”

With the monsoon settling in, Garvey said the insects will start coming out.

“We’ll see a lot of the ant population start mating, so you’re going to see lots of clouds early in the morning, late in the afternoon,” he said. “All species of ants start coming out with the start of monsoon season; ant populations will just explode.”

But ants weren’t the only insects expected to be out and about.

“This starts the termite season, so in about a month or two they’ll really start to consume on your house,” Garvey said.

“Bee populations are a little bit low, but we’ll get some forage, get some bloom, so the wild bee population will start moving again. And then the cricket population started a couple of days ago, so there were hordes of crickets coming up out of the fissures in the ground.”

The increase in insects could also be cause for concern for pet owners.

“We start to see tick populations in August,” Garvey said. “It normally takes about two weeks after the monsoons start to hit us and the humidity gets high enough, those eggs start to hatch, and boom we get those huge [numbers] of red dog ticks. They don’t really effect human’s that much, but they do effect your animals.”

Rodent incursion

Insects are something we’re all pretty used to dealing with, but it’s a while new ballgame when rodents come into the picture.

“We have a big roof rat population problem in the Valley, Garvey said. “It will explode in September, October, November and through the wintertime and it’s moving north through the Valley into Cave Creek into the wild areas. They’re a very aggressive rat, doing things they shouldn’t be doing in the first place. ”

Garvey said roof rats are more than pests. They’re destructive.

“They get into your fruit trees, consuming ripened fruit on the ground. With winter, they’ll penetrate your house … Once they get in the house, they move around in the insulation in the attic, they don’t really care to be down inside the home. They leave a lot fecal waste in that area, start having babies, then you end up having a problem.”

Garvey said it costs thousands to remove roof rats and that does not include replacing insulation that has been ruined by rat droppings.

Health hazards

Arizona is home to plenty of animals that are capable of dealing a deadly bite or sting — think scorpions and snakes — that, thankfully, tend to be scared of people.

“If you’re out in your backyard in your bare feet and you step on one, it will be extremely painful,” Garvey said. “Definitely call poison control.”

Garvey said the extreme heat experienced in the Valley last month forced scorpions to shift closer to homes.

“Where they were on your back wall, now they’re right up on your front door, around your house, on the back patio, up underneath your furniture.” he said. “Definitely get that checked out. We’re getting 20 calls a day from people who’ve never had scorpions before are now starting to see that population very close to their homes.”

Another animal that poses a hazard was the rattlesnake, which typically readies its body for hibernation during the summer months.

“They’re fattening up, picking off packrats, kangaroo rats and mice,” he said. “They’re going to group up around your house, your garage doors if you leave them open, they’ll get into areas around plant pots. You’ll find them up under bushes and trees in the morning. Coiled up or laying out flat in desert washes.”

A less deadly animal that could be a health risk is the Sonoran Desert toad. It is the largest native toad in North America and is a protected species.

But that doesn’t mean the toxin it secretes is any less dangerous.

“If you do run to one of those, don’t touch it with your hands,” Garvey said. “They are toxic. They secrete a small amount of toxin out their backs and through some wart looking areas [near their mouths].”

Sonoran Desert toads love to come up above ground after a heavy monsoon rain and find mates in puddles, run off ponds and swimming pools.

Spiders abound

No discussion on pests in the Valley would be complete without spiders.

“They can usually be found around leaking water, hose bibs, irrigation systems that are incorrectly installed, air conditioning condenser pipes,” Garvey said.

One of the most common Arizona spiders found during monsoon season is the black widow.

“They start to mate and start laying egg capsules out and boom, you’ve got lots of little black widows,” he said.

The widows are joined by another frequently seen spider in Arizona, the wolf.

“Lots of wolf spiders — they’re living inside your bushes, trees, plants and grass areas where’s there’s lots of waste or debris.”

Another arachnid that tends to blossom during the monsoon is the tarantula. Though the large, hairy spider looks intimidating, they are not known to bite people.


Garvey says the one way to keep these pests from coming around is to cut off their water supply, by not overwatering plants and keeping yards free of standing water.

He said too much water can attract mosquitoes in addition to the aforementioned pests. Mosquitoes, which can breed in small puddles, can transmit West Nile virus.

Pests can also be prevented by decorating your home with desert fauna instead of more traditional plants. Homeowners should also keep an eye out for anywhere pests may be able to get in.

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