phy·​to·​plas·​ma ˌfī-tə-ˈplaz-mə How to pronounce phytoplasma (audio)
: any of a group of bacteria that are related to mycoplasmas, cause plant diseases (such as aster yellows or elm yellows) by infecting phloem tissue, and are transmitted especially by homopteran insect vectors

Note: Phytoplasmas are assigned temporary taxonomic names because they cannot yet be grown in artificial media as required in bacterial nomenclature for a fully valid name.

For almost half a century, plant pathologists thought phytoplasmas were viruses. To this day, the inability to grow these bacteria outside plants or insects hinders efforts to get a handle on their biology and genomes.Evelyn Strauss

called also mycoplasma-like organism

Example Sentences

Recent Examples on the Web These look like the symptoms of aster yellows, a disease caused by a type of virus called a phytoplasma. Miri Talabac, Baltimore Sun, 28 July 2022 Usually, sap-feeding insects (aphids, leafhoppers, thrips, etc.) serve as the vector since the virus or phytoplasma can’t survive outside of plant tissue. Miri Talabac, Baltimore Sun, 28 July 2022 Along for the ride will be their good friend, the phytoplasma. New York Times, 1 Oct. 2021 The plant’s neighbors grow old, reproduce and die, but the phytoplasma’s eerily youthful host persists. New York Times, 1 Oct. 2021 It’s caused by a phytoplasma transmitted by an insect called a planthopper. Arricca Elin Sansone, Country Living, 25 Aug. 2021

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'phytoplasma.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Word History


phyto- + plasma (after mycoplasma), now taken as a New Latin genus name

Note: "In 1994, the name 'phytoplasma' was adopted by the Phytoplasma Working Team at the 10th Congress of the International Organization of Mycoplasmology to collectively denote MLOs [myoplasma-like organisms]." (Saskia A. Hougenhout et al., "Phytoplasmas: bacteria that manipulate plants and insects," Molecular Plant Pathology, vol. 9, no. 4, July, 2008, pp. 403-23.)

First Known Use

1994, in the meaning defined above

Time Traveler
The first known use of phytoplasma was in 1994

Dictionary Entries Near phytoplasma

Cite this Entry

“Phytoplasma.” Dictionary, Merriam-Webster, Accessed 27 Jan. 2023.

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