Any new treatments for rhododendron lace bug?

Asked June 29, 2020, 1:59 PM EDT

Hello, I am wondering if there is any new treatment out there for azalea/rhododendron lace bug? I have gone to this website in the past and received information regarding use of insecticidal soap, neem oil, thinning plants to allow for greater air flow, culling plants in full sun, use of predatory insects on juvenile lace bugs etc. I have tried all the above at the recommended time periods and continue to have a pretty robust lace bug population that does not seem to be getting better. I have not used the systemic insecticide that is known to kill bees, just can't do that with a good conscience but am feeling rather desperate now. I am now seeing adult lace bugs and fear that I may loose my beautiful mature rhodies. Is there any new treatment out there that doesn't kill bees?

Lane County Oregon

1 Response

Not aware of any new treatments for this bug. Although you mentioned several cultural controls, hopefully you have also tried out strong water sprays on multiple occasions. Hit both upper & undersides of leaves on multiple occasions. This may help reduce overall lace bug populations, not endanger natural predators, and reduce the need for other treatments.

Make sure the shrubs are not stressed due to drought stress during our warm, dry periods. Try irrigating every two weeks. This will certainly help ensure the shrubs aren't overly stressed (which could make them more susceptible to these bugs).

If you can't accept the level of lace bug damage you're seeing, you could consider using a systemic like dinotefuran (this is a neonicotonoid which is very toxic to pollinators like bees) with strict application restrictions. This systemic is only active for the season in which it's applied. If it's applied to the rhododendron according to label instructions AFTER the rhododendron AND any other adjacent plants have finished flowering, it should not be a threat to pollinators. Do NOT use any other systemics like imidacloprid because they may be active for several seasons and thereby pose a long term hazard to pollinators like bees.