Rhizoecus amorphophalli is similar to R. thailandicus by having 2 circuli (rarely 1 & 3), tritubular ducts, oral-collar ducts on dorsum and venter, 6-segmented antennae. Rhizoecus amorphophalli differs (characters of R. thailandicus are in parentheses) by having a smaller circulus (large) and lacking papillae on the apex of the circulus (present).
U.S. quarantine notes
This species was intercepted at U. S. ports-of-entry 8 times between 1995 and 2012, with specimens originating from India, Nigeria, and Thailand. We also have examined specimens taken in quarantine from China (Zingiber); Thailand (Zingiber); and Vietnam (unknown host). ScaleNet lists hosts in 5 plant families. It is most commonly intercepted on Araceae and Zingiberaceae. ScaleNet distribution records for R. amorphophalli include the Federated States of Micronesia (Turk Islands) and the Hawaiian Islands (Hawaii) in the Australasian zoogeographic region; Guadeloupe in the Neotropics and several countries in the Oriental zoogeographic region. One other species of Rhizoecus, R. cacticans Hambleton (Australia, on Echinocereus), has been taken in quarantine at U. S. ports-of-entry.