February 14, 2014 at 6:30 PM CST - Updated July 9 at 9:38 PM
SAN ANTONIO (AP) - A disease that has damaged citrus crops in Florida and elsewhere appears to be spreading in South Texas, prompting state agriculture officials to expand a quarantine.
The San Antonio Express-News reports citrus fruits turn green and their taste fouled by the disease known as citrus greening. The Texas Department of Agriculture last week quarantined a third zone in the Rio Grande Valley after a sampling survey found more trees infected.
Residents have been prohibited from moving citrus plants or plant materials outside the zones. Texas A&M University's AgriLife Extension Service has warned residents that their trees may be infected, even if they're not showing signs.
Greening is caused by bacteria carried by the gnat-sized Asian citrus psyllid. The disease poses no threat to people.