Dennis M; Hazelhurst, GA asks: I live in an old house with a two foot high crawl space under it. The crawl space is infested with spiders. I tried those bug bombs, but they didn't help. What else can I do?
Dear Dennis: If the insect foggers didn't work it means the aerosol pesticide didn't touch the spider. An insect fogger will kill the spider if it the insecticides reach where the spider is hiding. You need to carefully read the label of the aerosol bomb. Make sure it lists spiders as one of the insects it is meant to control. If spiders are not on the label, you're using the wrong product. Most home and garden stores like Home Depot or Lowes carry the products. You can find them at grocery stores like Kroger's, too.
Second, read the label to see the cubic footage the "bomb" is meant to cover. If you're trying to treat 4,000 cubic feet, but the label says it's meant to cover 3,000 cubic feet, you're going to be 1,000 cubic feet short of your goal. Remember, when figuring cubic feet you need to multiply the width times the length times the height of the area to be treated.
Foggers do best when set standing straight up or propped up at an angle not to exceed 45 degrees. With only two feet of height in the crawl space the aerosol spray won't be able to float all the way to the back of the crawl space. The spiders are running from the pesticides and are hiding in the back corners.
A pest control professional would use a fogger machine that would properly fill the space with aerosol or with a pesticide dust or both. You may want to consider calling for help.