[1][3] In 1854, Glover joined the Bureau of Agriculture of the United States Patent Office as an entomologist, and studied a wide range of topics, including sugarcane, citrus insect pests, plant diseases, soils, birds, mammals, reptiles, and Indian mounds, before joining the faculty at Maryland Agricultural College in 1859.
[1] In 1862, when the Department of Agriculture became an independent organization, Glover took up his appointment as United States Entomologist.
After a trip to an entomological convention in Paris, Glover strongly advocated for the fumigation of imports to the United States,[1] stating "It is well known that several of the insects most destructive to our crops are of European origin, and I would suggest that all foreign seeds and plants imported by this department be subjected to a careful investigation, and if found to be infested by any new or unknown insects, fumigation, or other thoroughly efficacious means of destroying them, should be used before distributing them through the country.
However, he struggled to find a publisher for his proposed book, and even refused to illustrate Insects Injurious to Vegetation by T. W.
[2] In 1872, he combined all 273 copper plates and 6,179 figures into Illustrations of North American Entomology in the Orders of Coleoptera, Orthoptera, Neuroptera, Hymenoptera, Lepidoptera, and Diptera.