In this work, we provide two case studies on interoperability and transfer of knowledge in the environment of a company dealing with plant protection. We find that the area of plant protection is highly oriented on working with knowledge. In this case interoperability of knowledge can play an important role in acquiring knowledge from different environments to solve specific problem in companies dealing with plant protection. Nevertheless, the concept of interoperability is well-developed on the level of data and information only.We stem from our previous works, where we defined a logical concept for the interoperability of knowledge on the level of knowledge units. The objective of this work is to show how to apply our process model of knowledge interoperability in a particular plant protection company. Two case studies are provided in order to demonstrate distinguishing between simple knowledge transfer and knowledge interoperability.