Reduced incidence of tomato yellow leaf curl virus and leafminer in a tomato cultivar in northern Thailand

Tomato yellow leaf curl virus (TYLCV), a whitefly-vectored begomovirus, is a major limiting factor for tomato production worldwide, including Thailand. Field evaluation of commercial tomato cvs. for resistance to the virus endemic in northern Thailand has not been reported. Experiments conducted in northern Thailand in 2011-2013 compared the field performance of three tomato cvs. from the US with a commonly grown Thai cultivar. There were few significant differences observed among the cvs. in marketable yield, and the severity of root-knot and root rot. However there were significant differences noted in TYLCV incidence; virus incidence ranged from 38 to 100% and 8-41% in experiments one and two, respectively. In both experiments 'Husky Cherry Red' from the US had the lowest TYLCV incidence, leafminer damage (Liriomyza sp.), and progression of foliar necrosis primarily caused by thrips feeding and possibly exacerbated by air pollution. TYLCV infection was confirmed by a simplified method of nuclear inclusion visualization with light microscopy in experiment one, and by virus inclusion detection and PCR in experiment two.