It’s been hot and dry for weeks and many Iowans who haven’t mowed their grass in a while are finding little patches of what looks like white cotton candy strewn around their yards. Ginny Mitchell, an entomologist at Iowa State University, says those are the webs of grass spiders and there are easily hundreds of species of the tiny arachnids. Don’t fear an invasion, as Mitchell emphasizes, they’re good bugs.

Mitchell, who’s the Education Program Coordinator of I-S-U’s Insect Zoo, explains why there are so many webs in our yards, perhaps dozens.

Eventually, we’ll have to mow again, which will ruin all of those carefully crafted webs, but that’s the cycle of life. Mitchell says don’t feel sorry for the spiders, as they will feel the vibrations of the approaching lawn mower long before it reaches their sticky lairs.

As fall arrives and the weather cools, some of those grass spiders may try to find a way into your house. Mitchell says to let them be, as they’re gobbling up -other- unwanted pests. The rest of the spiders will stay in the yard and many will make it through the frigid months ahead.

The grass spider webs are typically strung between the tips of grass blades, and you may spy a small funnel or entrance hole in the web. Mitchell notes there’s a fungus that can grow on grass, called dollar spot, which may look similar to the webs, but the fungus will also be down towards the roots.