You may apply Bora-Care once premise 2 has dried.
Bora-Care can be used at a 5:1 ratio for preventative treatment and will last for the life of the wood.
Yes, it is common to still see evidence after treatment with Bora-care. The beetles lie dormant for years and once they wake up they start consuming the wood, which is when we see the sawdust material. Now that it has been treated with Bora-care, once they consume the wood they will die.
You will need to do 2 application of Bora-Care. After applying first coat you will wait 20 minutes and then add the second coat.
When mixing Bora-Care, it is recommended to use hot water to make it easier to dilute it. The water should not be scalding hot, it should be a warm/hot temperature that will also be safe in case it splatters. It is recommended to dilute in a bucket first before putting it into the sprayer. The solution should not clog the sprayer if it cools but it would be best to use the mixture within 24 hours and not store or leave product in the sprayer because of the possibility of it being clogged after a long period of time.