GM Mosquitoes, Citrus and Antibiotics: Recipe for Disaster?

Citrus fruits are not native to the U.S., but they are now an integral part of Florida’s agricultural growth and state identity. Citrus trees came with Europeans in the 1500s and quickly began growing in Florida. In return for serving during the Seminole War several hundred years later, John Eaton was given land under the government’s plan. This was the birth of the citrus industry in Florida.¹

Eaton lived in what is now Orange County, where his experiments with grafting helped establish the crop. Farmers took them north into the Carolinas and Georgia to reduce shipping costs after the fruits were harvested,² but a freeze in 1835 destroyed all crops growing in those states.³ Farmers recognized the need for warmer winters and began moving the industry back to Florida.

In the early 1900s, the middle of the state was home to almost all of the entire citrus crops flourishing at that time. Another freeze hit central Florida in 1895, and, in one night, the entire industry was decimated. Few of the old groves were re-established, so the industry moved even farther south.⁴

Today, citrus is a $ 9 billion industry. Florida’s subtropical climate and its vast areas with sandy soil present ideal conditions for growing these brilliant, fragrant trees.

What Is Citrus Greening?

Citrus huanglongbing (HLB), also known as citrus greening, is a destructive disease that was first thought to be caused by a virus. It’s now known that the Asian citrus psyllid infects the trees with bacteria while it munches away on the leaves, twigs and stems. This hurts the tree’s ability to absorb nutrients.⁵ Once this happens, the tree produces sour-tasting fruit, eventually reducing production and dying.

To date, there is no cure for the disease and rapidly removing the trees is crucial to reducing its spread.⁶ The bacteria are able to infect most citrus trees, and even some relatives.

Since the disease was discovered in 2005, the number of acres dedicated to citrus growth has declined significantly. The disease has also been found throughout the southeastern U.S., the Caribbean, Asia and the Middle East.⁷

In the past 15 years, the infection spread rapidly across Florida and resulted in a 72.2% reduction in the production of oranges and a 20.5% reduction in the fresh fruit market overall.⁸ Even more disturbing than these statistics is the lack of scientific evidence about the bacteria.

Farmers are spraying antibiotics to protect the orchards, yet the bacteria have still not been successfully grown in the lab.⁹ The disease is associated with the gram-negative bacterium Candidatus Liberibacter. In the early stages, farmers find it difficult to make a diagnosis.¹⁰

Scientists are unsure how long a tree may be infected before symptoms begin to appear. Initially, farmers may find some thinning in the top branches with twig dieback and discolored leaves. An imbalance in sugar transport and accumulation also affects the nutritional content of the fruit, which becomes asymmetric and poorly colored as the disease progresses.

EPA Approves Antibiotics to Treat Citrus Greening

Some estimate that 90% of Florida’s citrus groves are infected with HLB.¹¹ Nearly two-thirds of the factories are closed, and packing operations have been cut from nearly 80 to 26 in the state.

The loss of groves and production could mean death to the state’s citrus agriculture that produces 80% of the orange juice consumed in the U.S. In the face of this devastating loss, the U.S. Environmental Protection Agency expanded the use of two broad-spectrum antibiotics in 2016, 2017 and 2018 that are medically important in treating human illnesses. These are oxytetracycline and streptomycin.¹²

It was hoped that application to citrus groves in Florida and California would prevent HLB. Yet, without adequate research showing the antibiotics could be effective and would not lead to further antimicrobial resistance, the decision reads as though the agency is throwing the kitchen sink at the problem and hoping it works.

In a press release following the announcement of emergency use of oxytetracycline in 2018, the Center for Biological Diversity pointed out three vital issues the EPA was failing to consider in the approval, writing:¹³

“In setting the tolerance level the EPA failed to analyze how the antibiotic could affect gut bacteria in humans that play a critical role in digestion, metabolism and immune system health.

The agency also failed to assess how fruit trees treated with the antibiotic year after year could affect the development of human pathogens resistant to the tetracycline class of antibiotics. And the EPA failed to consider the potential harm increased use of the antibiotic could cause to the nation’s most endangered wildlife.”

In late 2019, lawmakers expressed concerns that an overabundance of these antibiotics in the environment would only exacerbate antibiotic resistance.¹⁴ In a letter signed by seven lawmakers, the EPA was urged not to authorize the expanded use of streptomycin on farms in Florida and California after oxytetracycline had been approved in 2018.

Spraying has not solved the problem. The expanded use proposed in late 2019 allowed growers to use 650,000 pounds of streptomycin and 338,000 pounds of oxytetracycline every year. The University of Minnesota Center for Infectious Disease Research and Policy published part of the letter sent to the EPA, which said:¹⁵

“Antibiotics are life-saving medicines and, except in extraordinary circumstances, should only be used to treat specific illnesses in people and animals. EPA’s assessments appear to ignore scientific evidence, violate the principle of judicious antibiotic use, and could create unnecessary harm to human health by authorizing an unprecedented amount of medically important antibiotics to be used for plant agriculture.”

One Study: Agricultural Antibiotic Overuse Poorly Monitored

The amount of oxytetracycline and streptomycin sprayed on citrus trees dwarfs the amount used to treat infections in people. Yet, citrus trees are not the only place these two antibiotics are used. The University of Minnesota reports they are also sprayed on apple and pear trees to fight fire blight, another bacterial disease.¹⁶ Streptomycin is used on tomato seedlings before the young shoots are planted in a field.

Results from a recent study bear out concerns about the amount of antibiotics being sprayed on crops. Data were collected in low- and middle-income countries, revealing “that antibiotics are being recommended far more frequently and on a much greater variety of crops than previously thought.”¹⁷

The team gathered data from Plantwise, which is “an agricultural development program that trains extension workers to provide assistance and advice to farmers in countries in Africa, Asia and the Americas.”¹⁸

They gathered more than 436,674 records from 32 countries, which indicated the development program was recommending antibiotics for bacterial diseases, and also fungus, insects, mites and viral infections. The thing is, antibiotics only have activity against bacteria, so use for these other agricultural conditions is not warranted.

The University of Minnesota reported the study revealed “very little documentation or monitoring of antibiotic use in crops.”¹⁹ Data from the U.S. were not included in this study. The report also didn’t include information from China because China doesn’t report this information to CABI, an international nonprofit organization whose work is focused on agriculture and the environment.

For reasons that were not clear to the team, none of the records from Africa recommended the use of antibiotics. Some researchers believe streptomycin is the most commonly used antibiotic in agriculture across the globe, followed by oxytetracycline, which is sprayed when the local bacteria have developed resistance to streptomycin.²⁰

Phil Taylor and Robert Reeder from CABI were co-authors on the study, noting that antibiotics routinely sprayed on crops are usually mixed with agrochemicals, leading to concerns that interactions could create cross-resistance for antibiotics in bacteria. They quoted one study in which “resistance evolved 100,000 times faster” when bacteria were exposed to antibiotics and herbicides at the same time.²¹

Tetracycline-Dependent GM Mosquitoes Planned for Florida

As disturbing as this is, I ask you to now consider the thousands of pounds of oxytetracycline being dumped in citrus groves in southern Florida at the same time genetically altered mosquitoes designed to require tetracycline to reach maturity are being released in Florida. What could go wrong?

Oxitec is a company based in Britain that created a genetically modified mosquito planned for release in Florida in 2020. This will not be the first time genetically modified mosquitoes were released into the wild, as Oxitec also did it in the Cayman Islands, Malaysia, Panama and Brazil.²²

However, questions continue to abound as to the effect these mosquitoes will have on wildlife since once released, they can never be called back. The goal in releasing them is to reduce the local population of naturally occurring mosquitoes and reduce the transmission of illness associated with them.

The company reported that after releasing GM mosquitoes in three Bahian neighborhoods, there was a 90% reduction in mosquitoes. The mosquitoes are all male and have a gene inserted in their DNA that causes the insect to die before it reaches adulthood if it does not receive tetracycline. In the lab, they survive to maturity and can mate with wild female mosquitoes if they are given the antibiotic.²³

The assumption was that without access to tetracycline, the mosquitoes would die. However, with the thousands of pounds of the antibiotic being sprayed in Florida, it is often found in the soil and surface water and could create a nightmare that no one can predict.

The Time to Act Is Now — Here’s What You Can Do

Although genetic modification may sound preferable to insecticides or vaccines, there are still far too many unknowns to predict the future. Currently, there’s just not a way to predict the consequences to our environment and ourselves, because proper risk assessments have not been done.

As GeneWatch UK reports, “no evidence has been provided to support these claims” that the female offspring of the mosquitoes will die before they reach maturity.²⁴ There are questions about the effect these mosquitoes will have on other native species in the Florida Keys, too, such as bats.

It’s easy to believe that one person won’t make a difference, but as consumers, when we all act together, we can break the tight hold that leaders of large agribusinesses believe they have on our food supply. One of the best ways to do this is to buy your food from a local farmer who runs a small business and uses diverse methods to promote regenerative agriculture.

Consider joining a community-supported agriculture program so you can buy a share of the vegetables produced by the farm, which gives you a regular supply of fresh food. I believe this is a powerful investment, not only in your health but in your local community and economy as well.

By adopting preventive strategies to reduce toxic chemical pollution, you can also impact your personal health. Large companies like Monsanto and Bayer would like you to believe they control everything, but the reality is, they don’t.

You have the power in your hands to make a difference because it all starts with shopping smart and making the best food purchases for you and your family. I recommend visiting the following trustworthy sites for non-GMO food in your area:

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