Fusarium Fungus: Unpublished manuscript

(haga clic aqui para la versión española)

The US State Department and the Office of National Drug Control Policy (ONDCP) are negotiating with the United Nations International Drug Programme (UNDCP) and the government of Colombia to establish a research station in Colombia with an aim to "large-scale implementation" for applying the Fusarium fungus as a mycoherbicide to destroy Colombian coca plantations. The agreement includes the handover of more than 15 years of USDA research to the UNDCP.

The US Department of Agriculture’s (USDA) Agricultural Research Service (ARS) labels all narcotic crops as "weeds." While the concept of using herbicides against weeds and camouflaging cover foliage is not novel, however, using them against crops is. And while the promotion of mycoherbicides at first impression might appear to be a logical solution to the ongoing chronic problem of drug abuse, our investigation so far indicates that no independent agency has tested and evaluated the use of the mycoherbicidal strain EN-4 of Fusarium oxysporum. Its use is fraught with major uncertainties, with implications far beyond the areas and the time frames of its proposed use.

Our concerns about the proposed use of Fusarium in Colombia involve the following issues:

History

The Hawaiian Outbreak

Fusarium oxysporum is a fungus known to attack many plants, most notably food crops. During the 1960's through the 1980's, a wilting and dying of coca plants were observed at a USG research station in Hawaii (formerly operated by a major soft-drink manufacturer). The causative factor was found to be the fungal mold Fusarium oxysporum, inhabiting the soil. The source of the soil-borne Fusarium was not clearly determined, and several possible vectors were hypothesized, including potting soil or water contaminated by an indigenous Hawaiian Fusarium.

The US Government Response

As cocaine use grew in the United States, USG entities and other researchers initiated a series of detailed scientific studies into the strain of Fusarium responsible for killing the Hawaiian coca, focusing on determining and isolating the chemical causative agents of the disease; methods of mass-producing the fungus; developing application media for field use; and finding strains of Fusarium to kill other narcotic plants.

The Peruvian Outbreak

During the early 1990's, fully two decades after the fungus first broke out amongst Hawaiian coca plants, another Fusarium epidemic, known locally as "seca-seca" swept through the coca patches of the upper Huallaga Valley in eastern Peru. Coincidentally, one of the apparent epicenters of the disease was near the US antinarcotics fire base at Santa Lucia. Peasants in the area complained of their coca patches being sprayed from helicopters. In a debriefing of the US-funded Peruvian National Coordinator for Human Rights ("La Coordinadora") about their 1993 Annual Trip to Peru’s Huallaga Valley Jungle Region, "the delegation was struck, however, by the devastation caused by the fungus plague that is withering coca crops. They were assailed at almost every stop with accounts of US DEA airplanes spreading "fungus pods" over the coca fields..."

Non-specificity and effects on populations

Over the last decade, the disease spread to the Yurimaguas area, the northern limit of Peruvian coca cultivation as well as beyond Pucallpa in the east. During this period, disturbing revelations about its nature were documented by the US State Department through the US embassy in Lima, who were following its progression in their reports to Washington, D.C.. The embassy recorded reports that the Fusarium coca wilt disease was not specific to coca, but killed other crops, too: "Meanwhile, reportedly 3000 farmers in the Tingo Maria and Leonicio Prado area…have had to scratch for other means of earning a living, including panning for gold, when a plant disease, ‘seca-seca’ which had previously attacked coca plants broke out again in alternate crops planted in former coca beds." The disease also caused migrations of population, sometimes deeper into the jungle, or to other areas to avoid the plague: "Coca growers, especially those abandoning the UHV to move into other areas, generally attribute the industry’s collapse in the UHV to the fungus..." The US Government also contracted research in the field, and resultant tests showed that the same Fusarium that was killing the coca also killed tomato, achiote, and papaya: "the fungus is not specific to coca, but may infect other crops. This may be consistent with WINDELS, 1991, who states that not all special strains of F. oxysporum are specific, but may affect a wide range of hosts".^,

Longevity

A contract proposal submitted by researchers to the US DEA states: "It [Fusarium oxysporum] stays in the soil for years." our brackets[]. And, indeed, the Project Document contract between the United Nations International Drug Control Programme/Project of the Government of Colombia states that Fusarium "causes a debilitating disease and persists in the soil for several years^."2 Dr. David Struhs of the Florida Department of Environmental Protection wrote: "The fungus can remain in the soil for as long as 40 years."

The Florida experience

In 1998, the US Congress proposed that the ONDCP create a 10-year "Master Plan for Mycoherbicides to Control Narcotic Crops" in the US and in every drug-crop producing country in the world from Latin America, through the Middle East to Asia. By early, 1999, Jim McDonough, who formerly worked for the ONDCP was hired by Gov. Jeb Bush to head Florida's Office of Drug Control, was lobbying for the use of Fusarium against Florida’s illicit marijuana crop. After concerns were raised by other State entities, notably the departments of Environment and Agriculture, enraged citizens and the press the idea was dropped.

Mutagenicity

Secretary of the Florida Department of Environmental Protection, David Struhs wrote in a April 6, 1999 letter: "Fusarium species are capable of evolving rapidly... Mutagenicity is by far the most disturbing factor in attempting to use a Fusarium species as a bioherbicide. It is difficult, if not impossible, to control the spread of Fusarium species. The mutated fungi can cause disease in a large number of crops, including tomatoes, peppers, flowers, corn and vines, and are normally considered a threat to farmers as a pest, rather than as a pesticide. Fusarium species are more active in warm soils and can stay resident in the soil for years. Their longevity and enhanced activity under Florida conditions are of concern, as this could lead to an increased risk of mutagenicity." Mutagenicity in this case, would, in common terms, refer to the ability of some of the characteristics of the fungus to change. These changes could be in physical characteristics, toxicity, and host-specificity, among other things. Indeed, mutagenicity has been the subject, and indeed, the object of Fusarium research, even though the US Environmental Protection Agency prohibits the release of mutated fungi in the wild without prior approval: "Mutation research in our laboratory is directed toward generation of at least three kinds of mutants: auxotrophs (need help to grow in terms of added chemicals), survival cripples (can’t survive due to lack of sclerotia), and host range reduced pathogens."¹¹  

Misdirected Research

The research performed by ARS scientists and others quickly focused on a protein found in Fusarium that was partially responsible for the wilting disease in host plants. This compound was labeled "24kDa protein." Many additional scientific papers followed on this theme, but it appears the scientists focused on this novel protein, neglecting to perform basic analysis of Fusarium for the toxins generally associated with the genus. Nothing in the USDA literature available on the Internet or obtained through the Freedom of Information Act indicates ARS did studies on this particular Fusarium species’ toxicity to animals or humans, whether in natural or "mutant " form. There is, however, plenty of evidence of the toxicity of compounds produced by Fusarium species in mammals, including humans. Fusarium’s toxicity to animals and humans depends on several factors including local environment, climate, soil, competition with locally present microorganisms including fungi, delivery medium and concentration of the application, as well as the particular strain of fungus being applied. The toxins Fumonisin B₁ (Macrofusine or FB₁), B₂, and B₃ have been isolated from members of the genus Fusarium including a variety of Fusarium oxysporum. A 1995 ARS report states, "Fumonisin B₁ is an important phytotoxin and mammalian toxin. This is the first report of fumonisins produced by a variety of Fusarium oxysporum which is a well-known pathogen of economically important crops. It is possible that the fumonisins are involved in the pathogenesis of F. oxysporum." FB₁ can be a causative agent in pulmonary edema in pigs, and there is an association between FB₁ and FB₂ with human esophageal cancer, and is carcinogenic in rats. Indeed, its toxicity in mammals is of such consequence that reviews of its effects have been published. ^, Even the ARS abstracts on the Internet document health effects on animals: "Elevated plasma glycosaminoglycans in chickens with tibial dyschondroplasia induced by a Fusarium oxysporum isolate."

Many species of the genus Fusarium contain far more dangerous toxins than the aforementioned Fumonisin B₁ (Macrofusine or FB₁), B₂, and B₃. The genus Fusarium is also known to contain Nivalenol, a compound whose "potential symptoms of overexposure include, fever, nausea, vomiting, diarrhea, leukopenia, bleeding, sepsis; necrotic lesions of skin and mucosa," as well as Deoxynivalenol (Vomitoxin), "implicated as a chemical warfare agent."²³ Even more toxic is Fusariotoxin, which is also known as Mycotoxin T2: "Direct contact may cause extensive inflammation and tissue necrosis," and "Topical exposure has lead to systemic toxicity and death in experimental animals."

Indeed, Fusariotoxin (Mycotoxin T2) is considered in the Nuclear, Biological and Chemical warfare literature as a biological warfare agent. We include the above references to compounds found in other species of Fusarium because laboratory experiments have shown that fungi can produce varying amounts of chemically different toxins based upon substrate (host) and at different periods of its life cycle, etc., and it not unlikely that under certain conditions other novel toxins can be produced by Fusarium oxysporum.

Summary

Fungi are the world’s largest organisms. Because the majority live underground, and are only visible in the form of mushrooms during reproduction, they are taken for granted. However, issues surrounding the use the Fusarium fungus as a mycoherbicide have not undergone careful scrutiny by independent experts. The concept of killing off natural Amazonian mycoflora, flora, and fauna with massive infusions of a fungus that can inhabit soil for decades or more; that may produce undetermined amounts of known toxins affecting many forms of life; that may kill species other than the target species; and may produce unquantifiable mutations; in an area whose ecosystem supplies much of the planet’s oxygen, is a risky business at best.

Endnotes:

Revised 06/24/00