Lace Bug Treatment #224609 - Ask Extension

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Lace Bug Treatment #224609

Asked January 15, 2015, 1:53 PM EST

Our neighborhood in SE Portland is having a lace bug infestation (on azaleas and rhodys). Read about several treatments, systemic seems to work the best but have concerns about killing friendly insects. Any recommendations as to the preferred treatment and timing would be much appreciated.

Multnomah County Oregon

Expert Response

Lace bugs, fairly new to this area, are having a big impact on our landscapes. Control recommendations are evolving as we learn more about what works best here. A current discussion is the answer posted in Ask an Expert question 169985: https://ask.extension.org/questions/169985#.VLiNtXvLo0-
The publication referenced is "Lace Bug", EM 9066, http://oregonstate.edu/dept/NWREC/sites/default/files/em9066.pdf
Timing is important. To quote the other expert, Gail L., "Control will be best if you're able to knock back the first hatch of ALB. Monitor your plants, beginning in late April, as the eggs should hatch around that time through mid-May. When you see the signs and symptoms of the ALB nymphs, you can use an appropriate chemical control to knock them back."



Jacki Dougan Replied January 15, 2015, 11:10 PM EST
Thanks Jacki for the reply. Sounds like the predator route is just as effective as the pesticide route and I don't have to worry about killing any bees. Not sure if green lacewings or else ladybugs would be the best way to go. Can you use both at the same time or just one of them (will one eat the other)? Thanks in advance for your reply.
The Question Asker Replied January 16, 2015, 3:25 PM EST
The predator route is a slow, long-term plan not everyone is satisfied with. Here is what the University of California IPM page says: "Biological Control-Natural enemies of lace bugs include parasitic wasps, predatory assassin bugs, lacewing larvae, lady beetles, jumping spiders, pirate bugs, and mites. These beneficial species may not appear in sufficient numbers until after lace bugs become abundant, but their preservation is an essential part of a long-term, integrated pest management program. To increase natural enemy abundance and reduce lace bug damage, grow a variety of flowering plant species and provide partial shade to shrub species that are not adapted to grow in full sun. If applying pesticides, choose non-persistent, contact insecticides to minimize the adverse effects on beneficial predators and parasites." http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7428.html#MANAGEMENT
I'm not finding research about ladybugs eating lacewings. I did, however, find this article about reasons not to purchase ladybugs: "Ladybugs-better to attract them naturally" from OSU: http://extension.oregonstate.edu/gardening/ladybugs-better-attract-them-naturally
We are still learning how to manage for lacebug in the Pacific Northwest. For now, using the techniques you are comfortable with while keeping your plants as healthy as possible with appropriate watering and fertilizing is the best advice we can give.
Jacki Dougan Replied January 18, 2015, 6:47 PM EST

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