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!
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