The power of cross-indication testing: agrochemicals originally stemming from a different indication.

Cross-indication testing is the assaying of final compounds, but also their intermediates or side products, from one agrochemical indication against target species of other product lines. This approach has proven to be a highly successful source of lead compounds, which led to several important crop protection products. This review article describes, which herbicides came from fungicides and insecticides, how fungicides have been obtained from herbicide and insecticide leads and which insecticides have their roots in herbicide and fungicide chemistry. © 2022 Society of Chemical Industry.