Joro Spiders: What To Look For

Joro Spiders

Is that huge yellow spider in my yard a Joro spider? It might be, and it might be one of our native garden spiders. The two are confused often enough that this page exists mostly to help you tell them apart.

The Joro spider is an invasive species native to East Asia. It was first found in the United States in northern Georgia around 2014 and has been spreading outward since. It has now been sighted in Virginia. We have not yet encountered one in our own territory in southern Virginia and northern North Carolina, but the direction of spread means it is worth knowing what one looks like.

The female is the one people notice. Her body is about an inch long and her legs can span three to four inches. The abdomen is bright yellow with blue gray or black bands, and the underside carries red markings. The legs are dark with yellow bands. The male is much smaller and plain brown. The web is the other clue. Joro spiders build very large, three dimensional webs with a golden tint, often several feet across, strung between trees, on porches, along power lines and across walkways. A yard with many Joros can look draped in gold thread by late summer.

Our native black and yellow garden spider, often called the writing spider, is the usual lookalike. It is also large and yellow, but the yellow sits in blocks on a black abdomen rather than in bands, the legs are black with reddish sections near the body, and the web is flat, round and colorless, usually with a dense zigzag of silk down the middle.

Joro spiders are not considered a medical concern. They are shy, they retreat rather than confront, and their fangs are small enough that bites are uncommon and generally mild. The concern with an invasive species is what it does to the local insect population and to the native spiders competing for the same space, and that is still being studied.

If you think you have found one, take a clear photograph of the top and the underside of the spider and of the web, and note where on the property it was. We will identify it for you. Because these spiders are new to the region, a confirmed sighting is useful information for us as well as for you. A standard web dusting and perimeter treatment handles them the same way it handles other web building spiders.