Jun 03, 2013 - 10:05 PM
The best product to use outdoors for Black Widow Spiders is Demon WP. It kills on contact, and also leaves a residual to kill and repel others.
It sounds like the pest control company did what we call a "spray and pray". In other words they did a one time treatment, and probably told you it would do the trick. Not so. Most insects outdoors require at least 2-3 treatments to get control. This is only if they use the proper chemicals. Demon WP outdoors will kill the spiders.
Indoors, look under and behind everything with a good flashlight. You can also use Demon WP indoors to spray behind things, but also use ePest IPM Bug traps placed under and behind furniture to trap them.
Hope this helps.