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Gardening Questions Answered

Worms Are Defoliating My Redbud Tree

Large worms are eating the leaves of my redbud tree? It will soon be stripped.  What can I do?

REDHUMPED CATERPILLAR on a redbud tree. 
(Photo by Kathy Keatley Garvey)
REDHUMPED CATERPILLAR on a redbud tree. (Photo by Kathy Keatley Garvey)

To the Redhumped Caterpillar, your redbud is an 'eat-all-you-can' buffet.  It is readily identifiable by its bright red head and an equally bright red hump behind its head.  Its yellow body with red and white stripes is about an inch and a half long.  It will extend its buffet to include walnut, liquidamber, plum, and even cottonwood, birch and willow leaves at times. 

The damage is minor and spraying is not advised since they feed so late in the season and there is no harm to the tree.  Eggs are laid on the undersides of the leaves and can be discovered on close examination.  Prune out leaves while worms are small and side by side.  Control by spraying with Bacillus Thurengensis (BT) is also effective while the worms are small and side by side on trees of a size where this is possible.  Hand-picking can be effective on smaller trees. 

UC PUBLICATION 7474:  Redhumped Caterpillar  

Additional photos by Kathy Keatley Garvey:

Redhumped Caterpillars dining on redbud leaves.

Redbud leaves skeletonized by Redhumped Caterpillars.