|Leafcutter bee damage to bottle tree.|
A. Leafcutter bees can be pretty destructive to the appearance of many plants. They are pretty selective in the plants they choose. Other plants affected besides your Carolina jasmine and roses include bougainvillea, grape leaves, basil and other leafy herbs, photinia and ash leaves.
|Leafcutter bee damage to grape leaves.|
Part of the female leafcutter bee’s life cycle is to cut circles out of soft, thin, smooth leaves and use them to build nests for their young. The nests are constructed of individual cells, each with a ball of nectar, pollen and one egg.
They build these nests in cracks and crevices and holes that vary from about 1/4 inch to 3/8 inch across and deep enough to construct individual cells for their young. They also build nests in the stems of some pithy ornamentals like roses.
A frequent recommendation among Rosarians is to seal pruning cuts in roses with Elmer’s glue, a safeguard against leafcutter bees nesting in rose canes.
Leafcutter bees are important pollinators of commercial crops and were introduced into the United States from Europe. They have been used in Nevada for pollinating alfalfa primarily.
The bee is slightly smaller than a honey bee and won’t sting unless highly provoked or injured. Because they are such prized pollinators of urban vegetable crops, I encourage people to live with the damage they create or drape affected plants with cheesecloth to keep them away.
If you want to reduce their populations, another method to control damage, you can put out bee boxes, which are blocks of wood drilled with holes large enough to accommodate a portion of a soda straw. The females deposit their eggs inside the soda straws. You can dispose of the straws when they are full but before the young bees emerge.
Using insecticides is highly discouraged and it doesn’t prevent the damage anyway.