ar·​my·​worm ˈär-mē-ˌwərm How to pronounce armyworm (audio)
: any of numerous moths whose larvae travel in multitudes from field to field destroying grass, grain, and other crops
especially : the common armyworm (Pseudaletia unipuncta) of the eastern and central U.S. and Canada

Examples of armyworm in a Sentence

Recent Examples on the Web The moth family in this study feeds on roughly 350 plant species across North and South America, including the tobacco budworm, the corn earworm, and the fall armyworm. Laura Baisas, Popular Science, 2 Aug. 2023 To find out what was going on, entomologist Madoka Nakai and her team at the Tokyo University of Agriculture and Technology infected northern armyworm larvae with a common pox virus before introducing the immature insects to various parasitic wasp species. Mennatalla Ibrahim, Science | AAAS, 29 July 2021 Under the same situations, females of the true armyworm and the potato aphid exhibited significantly reduced calling behaviour. Seriously Science, Discover Magazine, 7 Oct. 2013 However, in the case of the armyworm there was a significant decrease in the incidence of mating under rising atmospheric conditions, suggesting an effect on male behaviour. Seriously Science, Discover Magazine, 7 Oct. 2013 Rebek said there are two kinds of armyworms: the true armyworm and the fall armyworm, the latter of which is the scourge homeowners are now facing. Christine Fernando, USA TODAY, 1 Sep. 2021 The bites of the armyworm are also a good clue, Pratt said. Sylvia Goodman, The Courier-Journal, 1 Sep. 2021 And the threat of swine fever and armyworm in China would diminish if the country wasn’t so dedicated to using the appetites of its people as a trade-war bargaining chip. Washington Post, 11 June 2019 The drought has also given rise to armyworms and other pests that can damage crops. Washington Post, 10 Oct. 2019

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'armyworm.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1815, in the meaning defined above

Time Traveler
The first known use of armyworm was in 1815

Dictionary Entries Near armyworm

Cite this Entry

“Armyworm.” Dictionary, Merriam-Webster, Accessed 23 Apr. 2024.

Kids Definition


ar·​my·​worm -ˌwərm How to pronounce armyworm (audio)
: any of numerous moths that in the larval stage travel in large numbers from field to field destroying crops (as grass or grain)

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