Azalea lace bug is a new pest that has decided rhododendrons are on the menu as
well as azaleas. This seems like a big problem because azalea lace bug has multiple
hatchings in a season and can do a lot of damage. The old rhododendron lace bug only hatched once a year in the Pacific Northwest.
Organic Control Methods
Systemic sprays and insecticides kill bees. It’s very important to use methods that don’t harm beneficial insects. Since drought and sun stressed plants are more susceptible, one method is to give these plants better care. Practically speaking, I would say irrigate even your old rhododendron trees that never seem to need a drop. Water them once a week during hot summer days as a preventative measure. Preventative methods are best. So far this spring, out of perhaps 60 gardens, I’ve only seen one garden that didn’t have these new pests. Preventative methods I’m recommending are building up green lace wings in your garden preferably before you have the pest or when you see that you do have it and better watering.
Using green lace wings, a beneficial insect, is another effective way to combat lace bug. You can purchase green lace wing larvae and apply them near your affected rhododendron, the idea is to build a population of green lace wings in your garden from March Biological in Sherwood, Oregon. Ladybug Indoor Gardens in Medford, Oregon can also be reached at: 541-618-4459541-618-4459. Please note, green lace wings are pretty, they remind me of Tinker Bell, sort of. Using the green lace wings does work, as my associate and friend Phil Thornburg, (Winterbloom) can attest. It took about 3 years but his plants have fully recovered and he has a nice population of the lovely green lace wings in his gardens as a bonus. Their latin name is Chrysopididae and you can look them up on Wikipedia for more details.
The chemical sprays I have seen recommended for lace bug are harmful to beneficials such as honeybees. My recommendations are purchase and apply green lace wings and irrigate azaleas and rhododendrons weekly in the summer. This will allow us to wait until a honeybee friendly solution to help us protect our plants is found.
Azalea lace bugs are here to stay.
For more details, download the informative Oregon State University flyer.