The beet leafhopper, Eutettix tenellus (Baker), is one of the most serious insect pests of western North America. Its chief importance is as a vector of the plant disease curly-top, which it transmits to beets, tomatoes, beans, melons, and many other agricultural plants. The virus apparently is introduced into the plant during the process of feeding, and is responsible for the frequent and often enormous losses to the sugar-beet growers and sugar manufacturers of the west. Apparently, the virus multiplies and remains active in the body of a leafhopper for some time, making it possible for the insect, after once feeding on a curly-top plant, to transmit the disease for a period of several weeks or even months. This study was undertaken to obtain information regarding certain of the internal organs. The writer also entertains the hope that a discussion, together with illustrations of the structures, might be of assistance to workers interested in a study of the internal structures to determine, if possible, the region or regions in which the virus is carried while in the body of the insect. Especial emphasis has been placed on the digestive tract and its accessory glands, as they appear to be the organs most closely associated with disease transmission.
Knowlton, G. F., "Bulletin No. 212 - Studies on the Morphology of the Beet Leafhopper" (1929). UAES Bulletins. Paper 170.