Texas seems primed for a terrific citrus season. Sets are good, the start should be early and timely rains promise larger fruit than last year. Hot days promise sweet fruit and cooler nights are bringing on good color. Aside from a trio of hailstorms in May, milder weather means the crop will be more cosmetically appealing than usual.
But lurking in the background is the specter of HLB — citrus greening disease — which was discovered in Texas in January.
The good news for Texas growers is that so far, HLB has not spread beyond the two neighboring groves where it was originally found, thanks to managed spraying programs for psyllid control and a database of HLB-fighting knowledge from researchers in Florida and elsewhere.
Spread by the tiny Asian citrus psyllid, HLB has wreaked havoc wherever it has appeared. Groves have been mangled or killed off completely by the bacterial infection, which first showed up in Asia in the 1920s. Since then, it has hampered the Asian citrus industry, spread across Brazil where it has done major damage, shown up in Florida a decade ago and was found in California in March of this year.
The disease is present in Mexico and across the southern United States, but nowhere is the problem more severe than in Florida. The University of Florida estimated that since 2005 HLB has cost the state 6,600 jobs, $1.3 billion in lost revenue to growers and $3.6 billion in lost economic activity.
Said Ray Prewett, president of Texas Citrus Mutual, “We’re certainly optimistic from a marketing standpoint of what the season could look like as far as the size of the crop and the quality of the crop. And there is some reason for optimism regarding HLB, but this is still a very dicey situation and we’ve got to move pretty fast. We’ve certainly got a new commitment to do that.”
The only HLB infection detected so far in Texas is in two neighboring commercial groves in San Juan, TX. Some of the infected trees have been removed and “there’s some very serious discussions going on about what we need to do with the rest of the trees and get something done here pretty quick,” Mr. Prewett said. “The industry stepped up and set aside some money for some compensation to growers to assist them in the burden of removing some infected trees. I think that’s very positive. We’re in the process of setting up a new group — so new we don’t even have a name for it — that is going to play an important role in the decision-making process and serve as a point of coordination for a lot of activities.”
Some may wonder why the infected trees were not removed immediately upon detection. That came in part due to reluctance to remove a grower’s livelihood when it was not known how widespread the infection might yet have been.
“With the latency of this disease the big unknown is where it might be,” Mr. Prewett said. “Early on people were seeing lots of symptoms that looked like they could be greening.”
Texas growers started treating those symptoms as if they were treating another infection, Phytophthora, and “these symptoms went away. How that looks here in Texas is a little different than how it looks in Florida,” Mr. Prewett said.
Another cause for optimism is the sheer amount of psyllid and tissue sampling that has been going on for several years. Since 2008 Texas has tested 43,511 psyllid samples and 22,359 tissue samples, which has “helped us come to the conclusion that though we don’t know how widespread it might be and we have to stay vigilant — I’m not going to jump up for joy that we have put the lock on the gate and kept the horse in the barn — but we can say not all the horses are out of the barn anyway,” Mr. Prewett said.
Still, said Craig Nessler, director of Texas A&M University’s Agri-Life Research, “I think HLB is probably going to spread. But we’ve learned a lot from Florida in terms of what works and what doesn’t, so I think the industry will survive until there’s a more permanent solution. It’s unfortunate that Florida had to go through this — and Asia and Brazil — and kind of make it up as they go along. But one of the wonderful things about agriculture is that information is put out in the public domain and the things that are working are disseminated very quickly so we can build off that rather than go through experiments that don’t work.”
Texas has a three-pronged approach to fighting HLB. The first is the detection and eradication of infected trees. Second is concerted spraying to control psyllids. Third is growing new citrus trees in an enclosed environment.
“Mature trees do not get impacted by this as quickly,” Mr. Prewett said. “Our last major freeze was 1989. We’ve gone a long time without a tree-killing freeze so the majority of our trees are a good size and this is in our favor. You’d be surprised how fast you can bring young trees up in an enclosed environment. The goal is a year from now folks will only be buying nursery trees that have been grown in a protected environment. Are we going to get there? We may have some shortages here but we’re moving toward getting our nursery industry into shape to make the shortage and time period as short as possible.”
Another fascinating option that is showing early promise is a citrus cultivar crossed with a gene from spinach that seems to resist HLB infection.
“Because we’re dealing with a crop that’s not an annual, it’s very difficult to control,” Dr. Nessler said. “If you do have resistance it’s difficult to move that into a breeding cycle because you’re talking about a perennial that may not bear fruit for several years. We’ve got a transgenic solution; it’s a spinach gene, so it’s not some gene from an animal or a skunk or something, it comes from another plant we consume on a regular basis. As far as I know there’s not a population of people out there who are allergic to spinach — a lot of people don’t like it I guess — but the protein itself is not allergenic, so I think it represents a viable solution to the industry.
“But we’ve got to do something in a hurry,” Dr. Nessler continued. “We’ve got the data that supports the resistance, it might be available in three to five years if we get approval. That’s the big hurdle, the federal government giving approval of the gene.
“The technology has been proven time and again to be safe and effective but that whole area of transgenics has been a problem with regulators because of issues with animals — and particularly humans — versus plants. With a plant we don’t give a rat’s butt — if it causes stunted growth or changes in leaf color, those events are immediately discarded, no harm no foul. You just throw those away and select the transgenic plants for propagation that are normal in terms of growth and development,” he said.
“It’s a plant gene into a plant so hopefully it won’t be quite as lengthy a process to get it approved. But it’s going to cost money and we’re going to have to have an industry partner to get it through the regulatory process. It’s kind of like approving a patent.”
Meanwhile, Texas citrus growers are holding their breath hoping HLB stays confined to the two groves where it has appeared.
Said Mr. Prewett, “It took the industry a while to get to the point of stepping up and saying, ‘We’ve gotta act on what we know and we better do it now rather than later.’ I know people will say it sure took Texas a long time to do something. Should we have done some things a little better and a little faster? Probably so. But we have reached the conclusion that this thing is not everywhere and we need to do something about it now and I feel real good about it.”