insect damage to maple?

Asked September 4, 2020, 2:43 PM EDT

A preexisting maple, maybe native, on my property is weeping black liquid. The maple also looks like the insides are being extruded out of the trunk. I expect this to be insects boring into the trunk and "sawdust" coming out. This has been happening since the spring and throughout the summer. Is this fatal?

Wake County North Carolina

1 Response

Hello, I am so sorry about your tree. You have 2 problems going on. First, the black ooze is due to Bacterial Wetwood. Bacterial wetwood results from an infestation of anaerobic bacteria that thrive in low-oxygen environments, penetrating the maple's inner wood. The germs enter the tree through damaged bark. Several bacterial species may infect the tree simultaneously. They form populations of wet tissue and spread over a period of years. Pressure increases in the maple's interior as the fermenting germ colonies release carbon dioxide. When pressure is high enough, it forces frothy fluid from wounds in the bark. The clear fluid darkens to brown or black with exposure to air. This doesn’t kill the tree but it weakens the tree which becomes attractive to other problem like the Ambrosia Beetle. This is your second problem. When a plant isn’t healthy it often gives off a gas that attracts harmful insects. That’s how the beetle found the tree. Yes, your right the little extrusions are due to the beetle burrowing into the tree creating tunnels where they leave an ambrosia fungus. This is there food source. They do not eat the tree nor does the fungus but numerous tunnels streets the tree a great deal. You do seem to have a significant population which may mean the tree has to be removed. Here is some options to treat and prevent from the Clemson University website. Prevention & Treatment: Heavily infested plants should be removed. If only a few branches are infested, they may be cut out. The life cycle takes approximately 55 days until the emergence of the next generation of beetles, so prompt removal or burning of the wood is important. Protective sprays on other susceptible plants may reduce their spread. Permethrin may be used as a trunk and scaffold limb spray beginning in March (see Table 1 for specific products). Thoroughly wet the bark. Multiple treatments may be needed during a season. Research indicates that spraying the infested trunks with permethrin may cause the beetles to leave the galleries they have already created. Since the beetles do not consume the host plant material, dinotefuran and imidacloprid systemic soil treatments are ineffective. https://hgic.clemson.edu/factsheet/maple-diseases-insect-pests/ I hope this helps. Please let me know if you have any other questions. Thank you for contacting us!