Biological pest control predatory midge "Feltiella acarisuga", and a ladybird "Stethorus punctillum". The bug "Orius insidiosus" has been successfully used against the two-spotted spider mite and the western flower thrips ("Frankliniella occidentalis"). Predators including "Cactoblastis cactorum" (mentioned above) can also be used to destroy invasive plant species. As another example, the poison hemlock moth ("Agonopterix alstroemeriana)" can be used to control poison hemlock ("Conium maculatum"). During its larval stage, the moth strictly consumes its host plant, poison hemlock, and can exist at hundreds of larvae per individual host plant, destroying large swathes of the hemlock. Not all biological control agents are directed at
What Is and What Should Never Be and What Should Never Be" was performed live at Led Zeppelin concerts between 1969 and 1973. A live version taken from a performance at the Royal Albert Hall in 1970 can be seen on the "Led Zeppelin DVD". Another was included on disc two of the live triple album "How The West Was Won". Two more versions were included in BBC Sessions. What Is and What Should Never Be "What Is and What Should Never Be" is a song by English rock band Led Zeppelin. It was written by Jimmy Page and Robert Plant and was included as the second