Spraying Termidor SC on the surface of soil is not going to offer a protective barrier like the trench and will only work for the general pests that contact the soil surface. Termidor binds to the soil that it is applied to and needs to be used in a trench 6 x 6 inches to offer the best protection. It also does not move through the soil after rain. Termites do not actually contact the surface so it would be best to go back and complete the trench in those areas that have not been done.
Termidor SC cannot be used to treat fire ants or their mounds. We recommend that you treat the individual mounds (as well as a broadcast) with Extinguish Plus Fire Ant Bait. It will take approximately 1.5-2 lbs per acre and 2-5 TBSP per mound. Please see our Fire Ant Pest Guide for more information and tips about treating for this pest.
Once Termidor SC is applied in the soil it will last up to 10 years.
Termidor SC will treat spiders but you would only be able to use the product outside. Termidor SC does not have an immediate knockdown but instead uses a delayed reaction kill which makes it especially effective for social insects like ants, termites and certain species of wasps. Most folks will use a residual product with a broader application area. Please check out our spider control kit for a better option.
Termidor SC is applied as a spray once every six weeks topically up against the foundation for insects that crawl on top of the soil, such as ants. If you are trying to treat for subterranean termites, you will want to dig a trench up against the structure, and if there is concrete up against the foundation you will need to drill to apply the product. Please take a few moments to review our article on How to Get Rid of Subterranean Termites for specific application instructions.
Inside the crawl space you would need to trench around any piers that hold up the home but the outside trench would be all that is required for the actual foundation if you are using Termidor. The Termidor will last for 10 years to protect your home. Please take a moment to look thru our pest control guide for termite treatment.
Depending on how heavy the rain was will depend on if you will need to reapply. If the rain was only light and you had just completed a Termidor treatment in a trench for termite prevention then you should be fine. If it was a heavy rain for a long period of time then you may need to reapply. If you were using the Termidor to spray around the perimeter of your home for ants and general insects, then you will likely need to reapply it on a day when no rain is expected for at least 24 hours.