Utah Plant Pest Diagnostic Lab

Spider Analysis

Question:

I found a spider in my garden among some weeds that matches the description of a black widow except it has three distinct white dots on its back.

Answer:

I have checked with a spider specialist in my department, Dr. James Pitts, and he says:

It could be a juvenile black widow. They sometimes have various markings (yellow, red or white) on the dorsum of the abdomen.

The dorsum is the upper side or back of an animal. So you may have found a juvenile black widow. Here is a link to a USU Extension fact sheet on spiders.

Since the spider is in your garden, I would advise avoiding its home (web) or removing it.

Poste on 1 Aug 2007
Diane Alston
Hort-Entomologist Specialist