Mites as vector of Tulip Virus X in stored tulip bulbs

Abstract: Tulip virus X (TVX) is a Potexvirus causing economic losses in tulip. Potexviruses aregenerally transmitted by mechanical contact and, indeed, several mechanical transmissionpathways for TVX have been identified during tulip bulb production. However, TVXtransmission does also seem to occur during bulb storage. Since mechanical transmission isexcluded in this period, a biological vector should be involved. The eriophyoid mite Aceriatulipae, the acarid storage mite Tyrophagus putrescentiae, and the acarid bulb mite Rhizoglyphusechinopus are the main arthropod pests of stored tulip bulbs. Therefore, we studied their putativerole in transmission of TVX during tulip bulb storage. We show that mites of each of thesespecies can carry TVX with them after feeding on TVX-infected bulbs. In addition, some of thehealthy bulbs acquired an infection with TVX when inoculated with mites. Although the currentsetup of the experiments does not confirm which species of mite transmit TVX, we have strongindications that mites are involved in transmission. Additional research with larger numbers ofindependent replicates is required to further prove the vector status of each species of mite, theefficiency, and mode of virus transmission. If our results will be confirmed, this would be thefirst case reporting a Potexvirus to be transmitted by mites, and the first case of an associationbetween acarid mites and a plant pathogenic virus. Consequently, TVX control in tulip bulbproduction should include an adequate control strategy of both eriophyoid and acarid mites.