Screen for rice leaffolder resistant rice genotypes in Taiwan

Rice is the major cereal crop in Taiwan and has the most cultivated area and crop production in Taiwan. Recently, brown planthopper, white backed planthopper, and rice leaffolder (Cnaphalocrocis medinalis Guenee) are three major rice pests in Taiwan. Planthopper resistant rice varieties have been widely used in Taiwan. However, we have no rice leaffolder rice variety in Taiwan yet. Thus, we are trying to do large screening of all Taiwan rice genotypes and expect to have rice leaffolder resistant rice genotypes. Furthermore, we have been tested several successful artificial insect diets (fall armyworm corn strain, fall armyworm rice strain, and even the suggestion recipes of rice leaffolder artificial diets in several publications). However, all tested artificial diet failed to rear rice leaffolder. Thus, we suggested that the previous corn seedling rearing technique is still the best rearing method for rice leaffolder. In addition, rice leaffolder in Taiwan is a migratory insect which immigrates from Mainland China every year. The maximum population of rice leaffolder in Taiwan is usually observed at rice tillering and panicle initiation stages on second crop season. However, rice leaffolder seems not over-winter in Taiwan. It may lack optimal host plants or cannot survive under lower temperature during winter season. Thus, we collected rice leaffolder throughout Taiwan to gain the information of the genetic variation of rice leaffolder in Taiwan and will use this information for further rice leaffolder screening process.