NiBor-D is a borate-based insecticide and fungicide powder manufactured by Nisus Corporation, registered with the EPA under number 64405-8. Its active ingredient is disodium octaborate tetrahydrate at greater than 98% concentration. The product can be applied as a dust, foam, or liquid spray for crack, crevice, spot, void, drain, and wood surface treatments.
Target Pests and Organisms
NiBor-D controls a broad range of insects and fungi. The label covers cockroaches, ants (including carpenter ants), small flies, crickets, silverfish, earwigs, boxelder bugs, cluster flies, centipedes, and millipedes. It also prevents and controls mildew and wood-decay fungi, making it a dual-purpose product for both pest and moisture-related wood damage.
Signal Word and Safety
NiBor-D carries the signal word “CAUTION,” placing it in EPA Toxicity Category III or IV, the lower end of the hazard scale. Despite the relatively low toxicity rating, the powder is a fine dust that can irritate eyes and lungs during application. The label calls for avoiding contact with eyes, skin, and clothing, and protective eyewear and gloves are standard practice when handling the product.
Mixing Ratios for Liquid and Foam
The label specifies two main solution strengths depending on the application:
- 10% solution: Add 1.0 pound of NiBor-D per gallon of water.
- 15% solution: Add 1.5 pounds of NiBor-D per gallon of water.
For either concentration, fill your mixing vessel roughly 80% with water first, then gradually stir in the powder until fully dissolved.
To convert the liquid into foam, add 1 to 2 ounces of a surfactant-foaming agent per gallon of a 15% solution. A dry foam uses a 20:1 expansion ratio (20 parts foam to 1 part liquid), while a wet foam uses a 10:1 ratio. Dry foam is better for filling enclosed voids where you want coverage without excess moisture. Wet foam works well for drains and trash receptacles.
Drain Treatments for Flies and Cockroaches
For drain applications targeting small flies and cockroaches, the label calls for a 5% solution: mix one 8-ounce packet (or 5 scoops using the included 1.6-ounce scoop) per gallon of water. Stir thoroughly until all powder has dissolved, then pour or foam the solution into drains. Adding a foaming agent lets the solution cling to the interior walls of pipes where fly larvae develop, rather than simply washing through.
For other crack, crevice, and void treatments where a stronger concentration is needed, combine three 8-ounce packets (or 15 scoops) per gallon for the 15% solution.
Wood Treatment Application Rates
NiBor-D is widely used for both preventive and remedial wood treatment against wood-destroying organisms like termites, wood-boring beetles, and decay fungi. The required concentration depends on the wood’s moisture content:
- Normal moisture content: One application of a 15% solution.
- Drier than normal wood: Two applications of a 10% solution.
In both cases, apply by brush or spray at a rate of 5 gallons of liquid solution per 1,000 square feet of wood surface. The goal is to thoroughly wet the wood so the borate penetrates into the fibers. For infested wood, you can also drill into the wood and inject the solution under pressure into insect galleries until runoff appears from exit holes.
During new construction, apply the liquid solution to all accessible bare wood surfaces at the same 5-gallon-per-1,000-square-foot rate. End-cuts of lumber can be treated by dipping them into a 10% solution for 1 to 5 minutes.
Dust Application Rates
When used as a dry powder (no mixing required), NiBor-D is applied directly into wall voids, box sills, roof eaves, attics, and soffits at a rate of 0.5 ounce (roughly 12 to 14 grams) per square foot. A hand duster or power duster works for these applications. The dust settles into cracks and voids where insects travel, providing long-lasting residual control as long as it stays dry.
For utility pole treatments, the label specifies a higher rate of 0.25 pound per cubic foot of the area being treated, injected or dusted into the pole interior.
How Borate Works
Borates kill insects through ingestion. When cockroaches, ants, or other pests walk through treated areas, the fine powder clings to their bodies. As they groom themselves, they ingest the borate, which disrupts their metabolism and digestive system. Death typically isn’t instant; it takes days, which allows foraging insects to carry the dust back to nesting sites and spread it to others.
In wood, dissolved borate penetrates the grain and makes the cellulose toxic to wood-destroying organisms. Because borate is a mineral salt, it doesn’t break down over time the way organic pesticides do. As long as the treated wood stays dry, the protection is essentially permanent. However, borate is water-soluble, so it will leach out of wood exposed to rain or standing water. This makes it best suited for interior structural wood, not exterior applications.