I hope it isn't rude of me to resurrect a thread from a few years ago, but I came across this thread while searching for information on controlling asclepias syriaca, more specifically, whether the rhizomes can be contained so as to prevent them from taking over (the seeds I'm not as concerned about). I have a couple of 1 year old syriacas in my garden (planted last year), as well as some new syriaca and purpurascens seedlings I have started indoors. I'm just now realizing/reading about how aggressive established syriaca can be. I have been fighting ongoing battles with Japanese knotweed and bindweed in my garden, which makes me very leery of inviting more rhizome-related trouble! I also have a fairly small garden, which means that if the syriaca begins spreading, it will quickly be popping up in my raised veggie beds on the one side, or in my rose/perennial beds on the other side. That said, is there a way to contain the syriaca rhizomes? Jazzygardener, above, mentions black plastic landscape edging--do others recommend this approach? Perhaps I'm overly cautious because of my J. knotweed experiences--those roots spread far too deeply underground for some black plastic to do much good, but J. knotweed is somewhat notorious for that so it may not apply to syriaca. If black plastic would work, what about large nursery pots sunk into the ground? Or alternatively, might it be a better idea for me to focus on better-behaved asclepias that would be more manageable? As mentioned, I do have some purpurascens seedlings and from my reading, it looks like there are many other asclepias varieties that are better behaved. I don't want to do the butterflies any disservice, but I don't know if I can take on another garden battle! What would you recommend? Thanks all for any thoughts and opinions. :)

I'm going to add some comments here that I made on another thread to maybe clarify some of my opinions on OE. As always my thoughts are my opinions based on many years of actually doing, not just accepting what others say. So they are only FWIW to be taken as a person chooses to take them. IMO common logic dictates that like with most infestation, disease or infection, the level they intrude an individual at can vary widely from minor to massive. That is commonly proved out with OE in Danaidae. If a larvae makes it through complete metamorphosis to an imago that can eclose and form OK, even if OE is present it was a relatively minor infestation in that individual. The opposite being if a larva at any instar, pupa or adult that has OE dies without getting through complete metamorphosis, that individual was obviously infested at a much higher level. Unfortuanately no matter at what level (with OE especially), failure to destroy any sick livestock whether it be OE, another parasatoid, viral or bacterial infection in most cases will promote the spread of any of any of them to other individuals. OE is the prominent one that will carry on to generation after generation beyond a given brood, and nothing but complete elimination of any brood within your control that might be infected with it will help slow it down in a colony. Why in my opinion when it comes to livestock even suspected of possibly having OE it's not worth taking any chances with them "for the good of the species as a whole". For those of use who did/do field work with Lepidoptera, that includes wild Danaidae livestock found or adults netted that show any possibilty of hosting OE. NOTE: Even if you have a very strictly controlled gardening and rearing rigime (which I doubt any of you have), you won't eliminate all of any OE present. So don't go slap happy destroying everything in sight. Instead be analytical and logical, and then decide what is reasonable for your own circumstances. Yes, livestock can have OE and not show any of the so called "visible" signs of it, which IMO are not proof positive of OE anyway and can be from other causes. In part why on my OE thread I offered some habit and condition factors that could also suggest OE is present as well even though they also do not prove OE and can also be from other causes. Bottom line, to prove OE is NOT present in an individual for certain takes a microscope or loupe. And in almost all cases if a larvae it will have to be euthanized to test with any certainty. A possibility to check for OE in pupa is to test the purge of the last instar larva for OE, but unforunately that is not 100%. I'm a lot more scientific in my appraoch to Lepidoptera than all of the folks here, so I don't accept things at face value. I am also skeptical of data from other sources that are not proven to me. The Internet and publications commonly breed misinformation about everything, including Lepidoptera, that is passed on by ACE's who probably got it from another one. So it's prudent not to trust every thing you read on the Internet or in books if it's not from a source you trust. Larry

Was the account that is missing emails in OE set up prior to the receive date on the emails? I would also check the Blocked Sender's List in OE...click Tools, Message Rules and Blocked Sender's to see if the senders have somehow been blocked. Pam

Try reviewing the Butterfly Gardening forum FAQ for topics like OE and black chrysalides, and/or post your question on that forum, it is commonly discussed there. I'm not sure that Monarch eggs/larvae infected with OE can even get to adult stage, but normal adults can carry and spread OE.