Pest surveillance: During 2007 - 2010, DOA has conducted the surveillance to determine the establishment of the bacterial disease Stewart's wilt (Pantoea stewartii subsp. stewartii) causal organism of Stewart’s bacterial wilt and leaf blight of corn.. The disease has the potential risk of being seed transmitted and is the global quarantine pest. Specific survey has been conducted in 142 sites from 20 locations of corn productions (13 sites of Chiang Mai province, 10 sites of Chiang Rai province, 13 sites of Tak province, 5 sites of Nakhon Sawan province, 5 sites of Mae Hong Son province, 8 sites of Lampang province, 4 sites of Lamphun province, 15 sites of Phrae province, 10 sites of Nan province, 4 sites of Uttaradit province, 4 sites of Phitsanulok province, 2 sites of Phetchabun province, 4 sites of Sakon Nakhon province, 6 sites of Khon Kaen province, 2 sites of Chaiyaphum province, 10 sites of Nong Khai, 10 sites of Nakhon Ratchasima province, 5 sites of Saraburi and 10 sites of Lopburi, 2 sites of Suphanburi province). 1054 samples of leaf blight symptoms were collected and examined for the presence of P. stewartii subsp. stewartii using ELISA detection kit for Pantoea stewartii (AgDia®, Inc., USA) and PCR following the protocol of Coplin et al.(2002). The result showed all samples were negative for P. stewartii subsp. stewartii in both ELISA and PCR methods.