It's my opinion that poplar is an interior wood and has no place in plug building even if sealed properly. I learned this thru experience.
I ain't grumpy and I don't know it all. Define sealed properly.
Maybe your buggers have some space age sealer that will make them impervious to water. Maybe you use it because it is a little denser and cheaper than pine, but I don't think plugs used for fishing will last long made out of it. Of course it won't matter if ya snap them off like we do
I'll tell you, just the high humidity from down south will rot poplar if it is not properly treated and cared for.