Sugar maples are very diseased trees. They have a lot of different insects that feed off of them. Surprisingly, unlike their close family member the red maple, sugar maples do not have any insects that do major harm to them. Their major concern is with fungus diseases. The worst and most destructive fungus disease that sugar maples get is called verticillium wilt. There is much to write about when it comes to this disease so I have created a separate page just for this disease.
Some of the very noticeable things you should look for are white spotting on the branches of the trees. You also want to look for die back in areas of the tree. The most common area is on the top of the tree. Anthracnose is less common but also a very dangerous fungus disease for a sugar maple. Anthracnose is a grouping of diseases that all have black spotting. So look for spotting on the leaves of your sugar maple. Another fungus disease that is very serious and should be taken care of immediately is called sapstreak. Sapstreak is unnoticeable unless you start pruning away at the limbs of the tree. There you will be able to notice on bigger limbs a browning of the core or woody area. This browning should be fairly rounded in shape with some streaks coming off of it.
There are over 22 different insects that attack the sugar maple tree. Unless there are serious infestations a sugar maple tree is unharmed. Unlike its counterpart the red maple that is mostly killed by insects the sugar maple is rarely killed by insects. Strange huh? Well I am not going to name off all of the insects for you. If you are interested in knowing about all of the diseases that feed off of the sugar maple here is a link to read more about them. Otherwise I can break it down for you and let you know what to look for. There are 3 different boring insects, 2 bud miners which can cause serious damage, many different leaf chewing insects, 3 different scales, several different rotting diseases that weaken the structure of the tree
Here are some things to look for in your sugar maple: