The research was conducted at the screen house of Indonesian Center for Rice Research (ICRR) to screen of 19 accessions by seedbox mass screening method. At 5 days old seedling of all varieties are thinned to remains 20 seedlings per row, then each set treatment infested by 5, 8 and 10 of 2-3 instar nymphs BPH/seedling from each biotypes 1, 2 and 3. The results showed that the seedbox screening method to obtain the stability of the resistance rice varieties to BPH must be infested 2-3 instar as much 8 or 10 BPH nymphs/seedling on 5 days old rice seedling. The stabilized varieties moderately resistant to all BPH biotype were Rathu Heenati, Swarnalata, Pokalli, PTB33, Kencana Bali 53, Kencana Bali 54, and IR 74. The population of BPH nymphs reduced height of rice seedling to cause stunting of rice seedling. Ability BPH nymphs to stunted rice seedling depend on to kind of BPH biotype, number BPH nymphs infested, and resistance rice varieties. Reduction seedling height by BPH biotypes 1 almost all stabilized varieties moderately resistant below 50%, but IR 74 and Kencana Bali 53 between 50-60%. Reduction seedling height by BPH biotypes 2 on stabilized varieties moderately resistant Rathu Heenati was smaller than 50%, but the other stabilized varieties moderately resistant were height reduction more than 50%. Reduction seedling height by BPH biotypes 3 on stabilized varieties moderately resistant Rathu Heenati, Swarnalata, Pokalli less than 50%, but the other stable varieties were reduction height more than 50%. The most stabilized rice variety was Rathu Heenati that stable on seedbox screening test, low reduction of plant height, and the little effect of population of BPH/row seedling. Kencana Bali 53 and Kencana Bali 54 can be used as differential varieties that were moderately resistant to BPH biotypes 1, 2, dan3. Likewise popular variety IR74 can be included as a comparison resistant in screening rice varieties to BPH. In the other hand screening methodology used 2-3 instar as much 5 BPH nymphs/seedling on 5 days old rice seedling resulted the unstable rice resistant.
