Question
I have the same problem as Karen who wrote you previously about 1000's of black bugs on her yuccas.  I have them in my front, back and side yards and have never, ever been invaded by bugs on these plants.  They totally destroyed the younger plants before I noticed them.  They are so very small that I didn't notice if they have red heads on them or not.  I sprinkled Sevin Dust on all of them and that seems to have stopped them in their tracks.  Is this okay to use on Yuccas?  I hope so, because I have sprinkled the dust on them until they like like they have been in a snow storm.  By the way, I am about 40 miles south of St. Louis, Missouri. I have had Yuccas for years and years, and have never seen such a thing on them before.  Are these Aphids?  Or just Yuccas bugs?  Is this common to the Missouri area?  Where do they come from?  Thanks for any help!  Pam

Answer
Hi Pam,
I don't know that Sevin will hurt the yucca.  I doubt it but Merit and Orthene are the pesticides recommended by Purdue University so I think I will stick with their advice.  The yucca bug won't kill the plant it will just make it look bad.  Sounds like you have it under control.  I think the bug is common wherever there are yuccas, so, pretty much all over the country.  I've seen it reported in Connecticut, New Jersey and Arizona to show you the diversity of where it is found.  The bugs are native to the Southwestern U.S. but have been appearing in all parts of Continental U.S.A. wherever there are yuccas.  The bug was probably introduced accidentally by various natural and artificial means such as coming back in shipping crates from the Southwest or in plants imported from the Southwest and then the bug was steadily spread all over the U.S.  You will need to observe your plant carefully as it may take several applications of the recommended insecticides before you will be successful in eradicating the pest.  I have found nothing that indicates the yucca bug is common in Missouri.  I checked the University of Missouri Extension and didn't find anything.  I haven't noticed any infestations here in Eastern Kansas where I live (Kansas City are).  There are heavy infestations in Ohio, New Jersey and Connecticut but the bug has been identified nationwide.  I hope this helps.
Tom