We have 5 spruce trees Ali go our fence line and for some reason that are all dropping sap. Seems to be coming from the needles but has been going on for weeks now. Earlier in the spring I noticed lots of the new growth has broken or eaten off. Any suggestions?
Dear gardener, I am so sorry that your spruce trees are dripping sap. How distressing for you. Unfortunately, without a photo of the branches with the leaking resin and without knowing what kind of spruce trees you are growing, I can only offer some suggestions, and hope you will follow up.
Adapting a previous posting with the Toronto Master Gardeners, I share the following with you:
Sap carries water and nutrients from the roots to all parts of a tree. Sometimes healthy plants drip small amounts of sap naturally. The leakage of sap is often a normal biological process of the trees and is not always a sign of a problem.
Mechanical damage: However, the dripping of sap may be in response to pruning, the trees being wounded by a lawnmower or squirrels, or attack by insects or disease. The most important step when such symptoms arise is to identify the cause. If you feel that the hole is there because a branch came down then watch the area for signs of disease. If pruning has not recently occurred, insect damage or fungal or bacterial cankers may be to blame.
Insect damage: If you see sap dripping from multiple holes that appear bored in the tree, suspect insects (although some woodpeckers also make holes and feed on sap). Bark beetles are a serious infestation and can be identified by the presence of sawdust, small holes in bark, leaking sap from bark and dying needles.
The Ldd moth (Lymantria dispar), previously known as the European Gypsy Moth, may also be affecting your spruce trees, including leaving oozing sap. The Ldd month mostly affects hardwood trees, but it also infests some spruce trees. The fact that the sap is coming from the needles indicates that the Ldd Moth is the potential problem. Ontario really had a bad infestation of this invasive insect.
For more information on the Ldd Moth, you may find this article interesting: The Ldd Moth
And this article as well which talks about Ontario’s infestation of the Ldd Moths: Ontario infested by Ldd Moth
Fungal damage: Cankers are dead spots on your trees, usually caused by fungi that grow under the bark. Typical symptoms of cankers are sunken areas along a stem, cracked, swollen or discolored stems. Sometimes resin leaks from a canker and forms a white patch on the bark. Trees may produce ridges of wound tissue around older canker infections as the tree attempts to restrict the fungus’ growth. As cankers develop, they can interfere with the branch’s ability to transport water and nutrients, resulting in the death of individual branches often referred to as “flagging.” Cankers can be a gateway for bugs, bacteria and other fungi to enter the living tissue of the tree. The following two articles will tell you more about canker damage:
what can you do about canker damage
spruce affected by canker damage
The first thing to do is determine why the hole is there. Diagnosis of fungal or bacterial cankers is difficult without specialized knowledge. If you feel there might be another cause, then I advise you to contact an arborist for advice. Landscape Ontario has information on finding certified arborists https://landscapeontario.com/
Happy Planting.
July 9, 2021