Wood Decay Fungus

• Some fungal diseases that occur in poplars cause the wood in the center of the tree's truck and limbs to begin to decay. In conditions favorable to fungus, the rot can affect large portions of the tree in months to years. Decay fungus infections common to poplars include artist's conk, varnish fungus rot, sulfur fungus, oyster mushroom, common split gill, hairy turkey tail, turkey tail and oak root fungus. Decay fungi are not always identifiable from the outside of the tree but are dangerous because the tree's integrity is weakened, causing branches or the trunk to break. Decay fungi are difficult to manage but can possibly be prevented by keeping the poplar healthy in its youth, pruning a young, growing tree to give it a good structure and cutting out dead or damaged branches throughout the tree's life.
  
  

Leaf Spot Fungus

• Foliage fungus infections like leaf spots develop fastest in cool and wet weather. Leaf spots aren't necessarily fatal to an entire poplar, but the condition makes the tree look dirty or sick and causes the foliage to fall early. Some poplar hybrids that can be purchased at nurseries are resistant to certain leaf spot fungi. If purchasing a young poplar, find out if it is resistant. If a tree has leaf spot, make sure to rake up all leaves and branches that fall from the tree to prevent more disease in the spring. If the infection is in a small area, try pruning the spotted leaves and branches. Keep leaves dry if possible, although make sure the roots get enough water. Fungicides will prevent an outbreak, but will not kill fungus that is already established.
  
  

Canker Fungus

• Cankers are visible dead spots on poplar tree branches or trunks that can be caused by a fungus, although cankers are not always a fungal issue. The sections of tree above the canker may die if the area of infection is large enough. Some cankers are man-made gashes in the tree bark that become infected with a fungal disease. Cankers can also lead to decay fungal diseases. Healthy poplars are better able to deal with cankers, so make sure the tree is well-watered and properly pruned. Dead branches that may cause wounds in the tree bark should be removed. When pruning a section of tree with a canker, sanitize the cutters after each cut.