Pest Alert: Aphids on River Birch

Aphids on river birch

   Every spring about this time the new leaves on river birch trees become a magnet for aphids.  The aphids start accumulating on the tiny leaves as they emerge and quickly cause them to be crinkly and distorted.

   As to whether you need to treat the tree for the aphids depends on how many leaves are infested and how badly they look. Chemicals that will control aphids include acephate, azadirachtin, imidacloprid, malathion, dinotefuran, insecticidal soap, pyrethrins + canola oil. 

   Soil drench treatments with imidacloprid can provide effective, long-term control of aphids, but such treatments are slow acting and must be applied before heavy infestations develop.

 I rarely treat my river birch for the aphids.  Usually lady bugs will find them and I end up with a ladybug nursery!

River birch trees grow quickly and by late spring the damaged leaves have fallen off.