State researchers said penicillin could save Florida's citrus crop from a devastating disease, but your carton of orange juice would probably have to come with a warning label if the wonder drug is used.

Citrus is a $9 billion-a-year industry in Florida, but for several years, production has been dropping — quite literally with fruit all over the ground at John Arnold's Lake County citrus groves. 

"We are losing volume due to fruit drop," Arnold said. "These oranges just fall right off the trees."

The U.S. Department of Agriculture projects Florida will produce 103 million boxes of oranges this year. That number was 147 million just three years ago.

One of the primary causes is a disease called greening, which caused by a tiny bug called the Asian citrus psyllid. The bug has cost Florida farmers an estimated $4.5 billion dollars over the last several years as sick trees produce tiny misshapen fruit that can't even be juiced.

"We literally have to make a judgment call on every tree and every fruit we pick — the big ones and leave the little ones," Arnold said.

Lake County's agriculture extension agent was at a conference on greening last month when the U.S. Department of Agriculture announced $30 million for additional greening research.

Almost half of that will go to a program at the University of Florida.

Treatment results announced that week of injecting penicillin into sick trees showed that trees were nearly back to normal in about 19 days, according to pictures from the Florida Department of Agriculture and Consumer Services.

Dr. Nick Place, dean of the University of Florida/IFAS extension, said Thursday that more research on penicillin's effectiveness will continue. For now, though, it's unlikely to be submitted for approval by the U.S. Food and Drug Administration.

"There are so many penicillin allergies and things like that it limits what we are able to use from that technology," Place said.

Research will continue on new root stocks, heat therapy and nutrition programs.