Q. Something is taking big bites or notches out of edges of the leaves on my Redbud tree. I never see any insects on the leaves, just the damage to the tree foliage. Do you have any idea what is causing this problem?
A. The writer sent some digital photos of the problem that made diagnosis easy. They showed the characteristic handiwork of leafcutter bees (Megachile species). These insects take circular bites out of the margins of the leaves of a number of plants, including redbud trees (Cercis canadensis) and roses (Rosa spp.). I have had them take pieces of leaves from sweet pepper transplants in my own garden. They use the pieces of leaves to line their egg cells. Leafcutter bees build their egg cells in hollowed-out twigs and natural cavities in plants, rocks and buildings.
The damage they cause is strictly cosmetic and does not truly harm the plant. They are not aggressive, and pose no threat to you or your family. Leafcutter bees are pollinators and should be considered beneficial.
No control measures are recommended. If you watch the tree closely, you should be able to see them at work. They clutch a piece of leaf with their legs, and fly off with it when they chew it free from the rest of the leaf. Imagine being agile enough to cut off the limb you are standing on and carrying it safely to the ground!