Two economically important eriophyoid mites, Aceria tosichella (wheat curl mite; WCM) and Aceria tulipae (dry bulb mite; DBM), were frequently confounded in the world literature until the late 20th Century. Their morphological similarity and ambiguous data from plant-transfer and virus-transmission trials contributed to this confusion. Until recently, there was a general lack of knowledge about the existence of species complexes and it was not possible to accurately genotype tested mites. In the present study, two WCM genotypes of divergent host specificity (MT-1 and MT-2) and one DBM genotype were tested for the acceptance of Poaceae, Amarylidaceae, and Liliaceae species that were reported or suspected as hosts of WCM or DBM. The MT-1 lineage colonized all tested plants. Onion- and garlic-associated DBM populations did not colonize tulip and wild garlic, suggesting that host-acceptance variability exists within A. tulipae s.l. Morphometric analysis did not discriminate closely-related MT-1 and MT-2 genotypes but completely separated both WCM genotypes from DBM based on the larger overall body size of the latter. Three morphological traits combined to discriminate between the DBM and MT-1 genotypes, both of which can infest Amarylidaceae bulbs. In total, these combined DNA sequence, host-acceptance, morphometrical results unambiguously separated two WCM and one DBM genotypes. Similar studies on additional lineages of both WCM and DBM should ultimately dispel previous taxonomic confusion between these two species. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 111, 421–436.