One year ago, citrus canker was found in young orange trees at a nursery in Avon Park, Fla. Ever since, state and federal agricultural officials have fought a widening battle to eradicate the deadly bacterial disease, last seen in Florida half a century ago. The canker now threatening the state's $1.2 billion citrus industry is resistant to every remedy except fire. But even after spending $24 million and burning nearly 9 million trees, officials are finding the canker in new locations. In the past month alone it has turned up in three nurseries and an orange grove.
Last week Florida took...