The 'Cheongcheong' is a 'Tongil' type rice variety that is used for rice resistance with the WBPH. It is a high yield plant with a complete abscission layer originating from 'Nagdong' is the main variety cultivated in our region and considered as positive and negative with WBPH resistance.
The WBPH were reared in room 18 cages (50 x 50 x 40 cm) in the greenhouse.
The WBPH can redistribute themselves on to the fresh plants.
All the lines were invaded from 2nd and 3rd instar of WBPH and the resistant lines were screened after 7 days, 14 days, and 21 days.
By contrast, WBPH resistance to imidacloprid was not obvious, and our research demonstrated that most WBPH populations from different regions remained sensitive to this chemical.
Fukuda & Nagata (1969) reported great differences in susceptibility to organophosphorus insecticides among geographic populations of WBPH. High levels resistance to malathion and fenitrothion were observed in Zhejiang, China during 1987-1991 (Mao & Liang 1992).
Since 2009 pymetrozine has been the priority insecticide to control WBPH in order to prevent virus diseases vectored by it (Guo et al.
The devastation caused by the virus transmitted by the WBPH drew the attention of the Agricultural Administration on WBPH control.
A single plant of each of the 71 RI lines ([F.sub.8], [F.sub.9], [F.sub.10]), 12 plants each of Asominori and IR24 parent, and eight [F.sub.1] plants were caged with WBPH in three experiments.
Ten weeks after seeding plants were infested with 8 to 10 cultured WBPH females for 2 d at room temperature to allow oviposition.
Plants were infested at 10 wk after seeding with 5 to 6 cultured WBPH females for 2 d at room temperature.
Eight weeks after seeding plants were infested with 10 to 12 cultured WBPH females for 3 d at room temperature.