We bought pine mulch for our front yard but the bag did not indicate that the pine mulch was treated for termites. Is there a prevention agent I can spray on the mulch to kill termites?
Also are there any sprays or treatments to use on my spruce tree to prevent any damage to our lovely 40 ft spruce? Are there any diseases I need to look for or prevent against for spruces?
Regarding the mulch, I can relate. I apologize I am not writing sooner because I might suggest returning it if you have seen any signs of termites present. I have the HSNY Librarian, Katherine Powis, searching to see if there is any new information we might be able to share. At this time I do not know of anything that you can treat your mulch with. Supposedly the termite issue in mulch often comes from bags or palettes that sit with excess moisture for lengths of time. The best is to look for a nice dry bag or palette of mulch next time you are shopping. From what I understand the termite mulch issue got significantly worse after Katrina because much of the mulch was coming from down south and exposed to more moisture than not for lengths of time prior to being shipped up north. Even some staff here in our office have been dealing with these issues in their own gardens. We will continue to research and let you know what we come up with.
Regarding your big spruce, simply taking good care of the tree as you have been is the best approach. The older trees get the less they need or like to be coddled. Mature trees should not be fertilized heavily or pruned aggressively because it takes them longer to acclimate to the changes. To minimize stress and encourage a healthy, long-lived tree practice basic proper upkeep. Prune any dead or diseased wood but otherwise keep pruning to a minimum. Feel free to top-dress the soil with an inch of compost or mulch, but do not add more than 2 inches because we want to make sure the roots continue to get enough water and fresh Carbon Dioxide. Try to avoid any compaction of the soil at the base of the tree. If we have extended periods of drought then the tree can tolerate some supplemental water, but by this point it is probably pretty used to "nature's watering schedule". Regularly scout for pest and/or disease issues. The lower and interior branches and needles will fall as the leader and tips of the branches continue to produce new growth. In terms of scouting for pests and diseases, you want to focus your attention more on the new growth and tips. Make sure that you do not see any browning of the needles, holes in the stems, or black fungal spots, or anything that seems blatantly different than the rest of the tree. When it comes to a mature tree like that spruce of yours I hesitate to take any drastic action until we know there is a detrimental situation present.