Potential for using borate mixtures as groundline preservative pastes

The potential for combining borates with differing degrees of water solubilities into pastes for remedial treatment of surface decay on utility poles was investigated using a small block test. Pastes containing disodium octaborate tetrahydrate (DOT) as a component tended to be most able to diffuse inward from the surface, but other borates with lower water solubilities, especially sodium tetraborate decahydrate and sodium tetraborate pentahydrate, moved inward at protective levels. Boron movement increased at the higher moisture level (60 %) and with prolonged incubation times (3 vs 6 weeks). The results suggest that combining borates with differing water solubilities would be an effective method for producing both immediate protection against fungal attack coupled with prolonged slow release to limit renewed fungal activity. Field trials are recommended to confirm these results.