San Diego County has received a two-year grant of $53,966 from the state Department of Food and Agriculture to contain an invasive weed species, county officials announced Wednesday. Ward’s weed has been found in Carlsbad, Del Mar, Otay Mesa and Camp Pendleton, in the only known infestations in North America, according to county officials. The weed is native to the Mediterranean and southwest Asia and threatens local fragile plant species and habitats by dispersing thousands of seeds.