Another example related to mutant rice varieties was the 2006-2007 outbreak of the Grassy Stunt Virus disease in the Southern areas, transmitted by Brown Plant Hopper. The Vietnam Government organized a campaign to mobilize different actions to control the pest. Our role was to transfer new tolerant varieties into production. In some provinces we supplied new varieties (including mutant as VND95-20, VND99-9, VN121 and VN124) and guided the production procedure in adverse conditions. As a result, in the Tay Ninh province and the Ben Cau district during the rainy season of 2007, the mutants yielded on average 5.1 t/ha compared to the local varieties that yielded only 4.1t/ha. Due to farmers having reduced insecticides, fertilizers and seed rate with a total spending reduction of 27,0% (about 175 USD/ha) in the production model of the mutant varieties, the added return from the use of mutants increased by 437.5 USD/ha over the concurrent ordinary varieties.