Texas Sugarcane Faces Small but Devastating Foe
By Hannah Jane DeCiutiis
The red-streaked leafhopper isn’t especially menacing as insects go. It’s a fifth of an inch long, if that, with thick red bands across its wings. But its abrupt discovery in Texas has put sugar growers on alert—not for what the bug is, but for the devastating disease it carries.
Sugarcane white leaf disease is caused by a phytoplasma called Candidatus phytoplasma cynodontis that infects the plant when the leafhopper feeds. That stunts the sugarcane’s growth and turns its leaves a creamy white. Researchers worry the disease could spell disaster for the state’s $200-million sugarcane industry.
“The species is here, and it’s established,” said Ashley Morgan, research associate for the Texas Invasive Species Institute. “If it reaches sugarcane crops, it could be pretty much game over.”
Texas is the country’s fourth-largest sugarcane producer behind Louisiana, Florida and Hawaii. Crops are grown almost exclusively on a 40,000-acre swath of farmland in the Rio Grande Valley and create thousands of jobs. The area’s high concentration of growers only adds to worries about sugarcane white leaf disease’s potential for destruction.
Native to Southeast Asia, the red-streaked leafhopper was first identified in Texas in 2008 when it turned up in a routine sampling of more than 18,000 invertebrate species in Bexar County. According to a 2010 paper published by the American Entomological Society, the invasive insect made up more than 85 percent of the sample. Today, the pest has been sighted in more than 50 Texas counties.
So far, no sugarcane crops have been infected, but researchers worry that once it starts the damage could be both fast-moving and comprehensive. Eradicating the insect is possible, but researchers say they need more time and money to figure out how to do it.
Sugarcane white leaf disease can cause total crop failure when it bites into a sugarcane field. It has caused more than $20 million in damages to sugarcane crops in Thailand each year since it was first observed in 1954, according to a 2014 paper published by the Sugarcane Research Institute in Yunnan, China. Thai farmers produce roughly $3 billion in sugarcane annually, so the damage is fractional; fields are scattered around the country, and many remain uninfected. Texas fields are all in one place, and the perpetual nature of the disease makes researchers worry that the damage here could be sweeping.
In 2014, researchers discovered that a leafhopper specimen had been misidentified in Kingsville, Texas, in 1971, meaning the insect has had decades to establish itself. So far, however, the leafhopper has mainly fed on King Ranch Bluestem grass— an invasive grass that also comes from Southeast Asia. The leafhopper’s current preference for the grass is a lucky break for now, but researchers are fairly certain that it will eventually get into sugarcane.
It is unclear how the species first showed up in the U.S., but Morgan said it might have entered on a cargo ship, possibly on grass being imported from Asia. It’s also possible the Texas breed of leafhopper doesn’t carry sugarcane white leaf disease, at least in a high concentration. But researchers aren’t willing to take that chance and require more funding to determine the exact nature of the threat.
Yet Jerry Cook, executive director of the Texas Invasive Species Institute, said such funding is hard to come by. TISI’s efforts to secure grant money from the U.S. Department of Agriculture to investigate the leafhopper and its consequences have so far been unsuccessful.
“USDA is dealing with lots of stuff, and their budget just isn’t big enough to work on everything,” Cook said. “They do a great job with the budget they have, but since this isn’t affecting the crops right now, it just doesn’t get the same priority.”
At the state level, Cook said, funds simply aren’t available. The Texas Department of Agriculture has been aware of the threat for more than two years, but Cook said like USDA, the state department is limited in which threats it can focus on at a given time.
While state and federal budgets can only account for pests currently damaging crops, Cook said it is important for researchers to detect pests as early as possible so that researchers have the best possible chance to reduce damage from an invasive pest, and it has saved crops in the past.
In 2014, sugarcane growers in the Rio Grande Valley faced down a similar threat from the sugarcane aphid. First discovered in Florida in the 1970s, the aphid is so named because it fed almost exclusively on sugarcane at the time of its discovery. Danielle Sekula-Ortiz, invasive pest manager at Texas A&M AgriLife Extension Service, says the species was discovered in Texas in late 2013.
“After some trials, we noticed that the sugarcane aphid was actually feeding on grain sorghum in Texas,” Sekula-Ortiz said. “We decided to check sugarcane and corn to make sure they aren’t in those two crops—we found a few, but we noticed they did not develop nearly as much.”
Grain sorghum is also a prominent crop grown in South Texas and is primarily used for livestock feed.
Researchers at AgriLife studied various ways of spraying the grain sorghum with insecticide to kill the aphid. They then worked to educate farmers about how to protect their crops and the industry saved at least $65 million, Sekula-Ortiz said.
“Our growers down here in the valley grow around 350,000 acres of grain sorghum per year,” Sekula-Ortiz said. “The losses this past year would have been immense if we had not done a lot of outreach.”
Adrian de los Santos, member of the Tip of Texas Ag Producers Cooperative in Hidalgo County, said the co-op has nearly 30 acres of sugarcane crops that are grown without any pesticides, which makes pest prevention all the more urgent.
“When the cane is growing, it’s hard to control anything that’s growing on it,” de los Santos said. “It’s so thick, there’s nothing that you can do to stop it other than destroying the crops, which would be devastating. Our main goal is prevention.”
Bill Crawford, founder of Hondo Cane Co. in Rio Hondo, said he’s terrified about the red-streaked leafhopper threat. Hondo Cane produces juice from 6 acres of sugarcane grown in the Rio Grande Valley and is also a member of the Tip of Texas co-op.
“This business is so brutal,” said Crawford. “But farmers are eternal optimists—you put all your money in up front and you see what grows in a year. When farmers hear something like this, they’ll just say ‘OK’ and go plant anyway. What else are you supposed to do?”
Representatives from the Rio Grande Valley Sugar Growers Association declined to comment for this story.