Testing the differences of LT50, LD50, or ED50

An approximate method is derived for testing the differences of LT 50 , LD 50 , or ED 50 , which indicate the temperature or dose needed to kill or damage half of the plants, respectively. It is assumed that a logistic model is used to describe the relationship between probability and a treatment variable in the framework of generalized linear mixed models or generalized linear models. The method is based on the delta method and the Wald test. In the forest sciences, this method can be used when dose, temperature, or time responses are compared in different treatments, cultivars, or origins.