Insects are directly and/or indirectly associated with plants, and interactions of them have long been studied in many countries. The suborders Heteroptera and Auchenorrhyncha, in Hemiptera which is the largest hemimetabolous insect order, are also closely associated with various plants as their hosts and habitats. In addition, some groups of Auchenorrhyncha are known as the vector to transmit pathogens such as phytoplasma and virus to the plant. However, there have been a few researches on interaction of insect groups and plants, although it is important to construct data and to understand their interaction for application in various fields. In this talk, the current research on interaction of two suborders and plants is presented. The importance and direction of future work are also discussed.