corn rootworm
noun
: any of several chrysomelid beetles (genus Diabrotica) whose root-eating larvae are pests especially of corn
Example Sentences
Recent Examples on the Web Trapping and studying the corn rootworm has been Verónica Calles Torrez’s route to exploring North Dakota. 
NBC news, 15 Sep. 2021 The western corn rootworm beetle grows to only the length of a grain of rice. Tess Joosse, Scientific American, 16 Aug. 2021 Cucumber beetle larvae, also known as corn rootworms, feed on corn roots, causing plants to weaken and collapse. The Editors Of Organic Life, Good Housekeeping, 5 Apr. 2016
NBC news, 15 Sep. 2021 The western corn rootworm beetle grows to only the length of a grain of rice. Tess Joosse, Scientific American, 16 Aug. 2021 Cucumber beetle larvae, also known as corn rootworms, feed on corn roots, causing plants to weaken and collapse. The Editors Of Organic Life, Good Housekeeping, 5 Apr. 2016 Word History
First Known Use
1892, in the meaning defined above