Effectiveness and Uses of Borate
Dr. C. Douglass Mampe
Borate Insecticide, from U.S. Borax Inc., is one of the new borate products containing the active ingredient (a.i.) Disodium Octoborate Tetrahydrate. The product's ability to diffuse into wood to various depths provides a new alternative for controlling wood decay and certain wood infesting insects. The borate formulation offers pest control operators the maximum degree of diffusion of borate in wood. borate can control current infestations and provide long term protection against attack by wood-destroying organisms.
borate should not be confused with boric acid. Boric acid is not designed for wood treatment and will not diffuse or penetrate wood as well as borate. So don't think about substituting boric acid for borate. borate diffusion in wood depends upon the characteristics of the wood, such as age or type, and its moisture content. The softwood Southern yellow pine permits good diffusion, while another softwood species, Douglas fir is more difficult to penetrate. Dry wood (15% moisture or less) absorbs borate solutions well on the surface. Higher wood moisture (20°/, or higher) cannot absorb as much solution on the surface, but the higher moisture aids in deeper penetration of borate. The bottom line is that dry wood accepts more solution at the time of application, but wetter wood provides deeper diffusion of borates. In the most common wood species, Southern yellow pine, one spray application of borate to dry wood may produce 1% a.i. (2,000 ppm B) at a depth of 1/4 to 3/8 inches. The total penetration is about twice this depth, or about 1/2 inch. Spray treating dry Douglas fir with one application of borate may produce about 1% a.i. 1/8 to 3/16 inches into the wood. The same treatment of moist Douglas fir (25% moisture) may produce 1 °/ a.i. at the center of a 2 x 4, or a depth of 3/4 inches.
Most of the borate remains in the top 1/8 inch when applied to dry wood. The surface layer may have 4-6%% a.i. (8,000 to 12,000 ppm B) after the first spraying. A second application of 10% borate provides more borate (about 35-85% more) on the surface and below, depending on how long you wait between applications. Other borate formulations provide no better penetration when compared under identical conditions. You might wonder why you need to make two applications if the depth of diffusion is no greater. The reason is that more borate diffuses below the surface and provides kill of the target pest deeper below the surface than will one application. This reduces the likelihood that beetles will emerge from treated wood. That means greater customer satisfaction!
Mixing boric acid for pesticide
borate is a powder, which is formulated to mix with water at the rate of one pound per gallon. It is recommended that a dust mask, not a respirator, be worn when mixing large quantities. Stirring the solution will cause the borate to completely dissolve into the water, resulting in a clear solution which is very stable. Water temperatures down to the freezing mark will not cause the borate to drop out of solution. Other borate formulations are not stable after mixing. When they drop out of solution, you may have difficulty in redissolving them. borate, however, will not break down in water and solutions can be stored in sealed, labeled containers until needed.
Applying boric acid for pesticide
Once mixed with water, the boric acid for pesticide solution can be brushed, (foamed) or sprayed onto wood surfaces. Either method leaves approximately the same amount of borate on the wood surface. A spray application usually requires less time, so you save labor costs by applying it as a spray. The wood surface should be free of paint or other protective coatings. boric acid for pesticide will not penetrate such coatings. The surface should be treated until wetted, just short of the point of runoff. Once dry, there may be crystals on the wood surface, however, this should not interfere with any exterior treatment. If the wood is on the exterior or otherwise exposed to occasional wetting, the surface should be sealed following the borate application. Sealing should be done after the treatment is completely dry (at least 48 hours). boric acid for pesticide will not interfere with sealants such as paint, varnish or waterproofing compounds. If termites or deeply seated wood boring insects, such as old house borers are the target pest, you may need to drill and pressure-inject thick wood to reach the pest. borate will diffuse much greater distances when moving with the grain of the wood than it does across the grain. Drilling and pressure injection permits borate to diffuse with the grain below the wood surface. To obtain the necessary diffusion and borate concentrations to control such pests, it is recommended that the following procedures be used to accomplish good control in thick wood:
Treating through the edge of a 4 x 10-drill holes every 8 to 10 inches along the edge. The holes should nearly reach the opposite edge. This requires a long, thin drill bit approximately 9 inches in length (or longer if the wood is thicker).
Treating through the face of a 4 x 10-drill holes approximately 3-1/4 inches deep (just short of the opposite face) 12 to 16 inches apart along the center line to create a diamond pattern. Wider or thicker wood members need additional rows of holes or deeper drill holes to achieve total coverage. The holes are usually 7/64 or 1/8 inch in diameter, but should be of a size that permits an injection tip to be a force fit into each hole.
Regardless of the drilling pattern, inject borate into each hole using a tight fitting injection tip and 75-100 psi (a compressed air hand sprayer can be pumped up to 75 psi or more). Inject each hole for 15 to 60 seconds. Apply the maximum if the holes will accept the solution. Be prepared to wipe up excess borate if it exits the drill hole following removal of the injection tip.
For native Subterranean termites, a concentration of 1% a.i. (2,000 ppm B) in the wood will prevent attack. One to 2°!° a.i. (more than 2,000 ppm B) is needed to deter Formosan subterranean termites from feeding. However, when they consume wood with lower borate content (as little as 100 ppm B), it functions as a slow-acting bait. The slow-acting nature of borate permits the toxicant to be carried back to the colony and reduce its vigor. The surface of the wood, after the recommended two applications, usually contains 6-9% a.i. (12,000 to 18,000 ppm B). The concentration gradually drops off deeper in the wood. Even though there are higher concentrations at the surface, concentrations as low as 0.1 °f° (200 ppm B) can have an impact on termites.
Concentrations of borates in wood effective for Subterranean termites appear to be equally effective against drywood termites and dampwood termites.
Wood boring beetle larvae are killed by 0.4°% a.i. (800 ppm B). A spray application can provide a treated zone of 1/4 to 1/2 inch protection against wood destroying beetles. Even if borate does not diffuse deeply enough to reach all larvae, the larvae will tunnel back into the borate as they mature and be controlled. The high concentrations of borate left on the surface will also prevent reinfestation.
In the case of Old house borers, however, larvae are deep in the woodas is often the case in log homes. The wood must be drilled and pressure injected with borate to eliminate the infestation. A surface treatment will prevent reinfestation and often kill larvae near the surface, but the customer may still hear larvae chewing well below the wood surface. Even with drilling and pressure injecting, some larvae may not be reached by borate immediately. As the larvae tible to borate. Concentrations of borate in the wood as low as 0.3% a.i. (600 ppm B) will provide total control. Wood wet enough to support decay fungi will also enhance borate diffusion. One application should be sufficient to control the infection, although a second application will increase the borate concentration throughout the diffusion area in the wood.
boric acid for pesticide like all Borate matrials is a poor contact insecticide. Wood surfaces treated with borate will not be attacked by carpenter ants but contact will not kill the ants. Dry borate powder should be injected into carpenter ant galleries and nesting areas for control.
borate provides you with a long lasting, odorless, low acute toxicity pesticide/(fungicide) to eliminate or prevent infestations in wood by a wide range of wood destroying organisms. It can be a substitute for fumigation in some cases. It will last longer than other insecticides and penetrate wood better. And the customer can paint, stain or apply other sealants to the wood surface later.
Dr. C. Douglass Mampe is a nationally known consultant in the pest control field. He is president of DM Associates, Monmouth Beach N.J., and a contributing borate, like all borate materials, is technical editor of Pest Control magazine.
((borate will not affect mold spores) Kenn))