The current debate on the general decline of insects throughout Germany lacks well-documented long-term studies. This is due to the immense diversity of insects, the associated effort for identification, and finally the lack of standardised collection procedures. We revisited own studies on the abundances of leafhoppers and planthoppers from the years 2008 to 2010, which are based on inventories from the 1950s and 1960s. Historical and more recent data are comparable to each other thanks to the application of standardised methods in the historical datasets. Here, we add newly calculated data on changes in biomass in order to facilitate comparison with other studies that have received very much attention. We were able to calculate regressions between dry weight and individual size for the main auchenorrhynchan groups, which allow us to deduce biomass from abundance. The determined decrease in biomass for leafhopper and planthopper populations on protected dry grasslands in eastern Germany amounts to 54 %. For wet grassland in Lower Saxony, it even amounts to 78 % over a period of 40 to 60 years. These data underline that currently discussed losses in insect biomass are indeed tremendous. Thus, the phenomenon should be considered universal. Measures to preserve and re-establish insect populations should therefore be taken swiftly.