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Frequently Asked QuestionsWhat’s All The Fungus Fuss About?In the current debate, plant pathologists familiar with the details of the particular mycoherbicide discussed and with the accumulated body of scientific data, believe the evidence is sufficiently compelling to proceed with a systematic program of field trials consistent with both mycoherbicide registration and with international standards. This is what happens normally when non-narcotic plants are the subject of control. However, in this instance, opponents of the prevailing standards, none of whom are plant pathologists, insist there are too many unresolved issues for even a controlled test to occur. Their alarmist concerns have been relayed to the media, but with little scientific validation to support their claims. These fearmongering approaches are even more misleading at the lay reader’s level. What are its most persistent claims?
1. Toxicity Claim: “Fusaria are dangerous to public health; they produce fusariogenin, a known toxin.” Answer: This misleading statement comes from confusing the genus Fusaria, with the species (There are approximately 60) and subspecies Fusarium oxysporum forma species Erythoxyli. This latter is nontoxic as measured by USDA testing at Tifton, Georgia. This mistake is the same as stating that the mushroom genus Amanita is poisonous because some species produce ananitine, a known toxin, while the species Amanita calyptrate is an edible and quite excellent food. There are even forma specialies of Fusarium oxysporum that produce mycotoxins (and most of these already exist in South American agriculture) However, the latter is not the case for the strain of interest in coca mycoherbicide control.
2. Human Health Claim: “The death rate caused by Fusarium infections in humans is 76%.” Answer: This statement is entirely misleading and suffers from the same faulty logic as the toxicity claim. Generalized statements about the Fusarium genus attacking humans are not applicable to Fusarium oxysporum, forma specialies Erythoxyli. In the cases of the referenced death rate statistics, the victims were all immune-suppressed cancer patients whose defense levels were so low as to make them highly vulnerable to almost any infection. Furthermore, the normal EPA mycoherbicide registration procedure requires extensive testing related to animal and human health, thus ensuring that no unhealthy products would be released.
3. Pathogen Host Range Claim: “Some strains have a broad host range, infecting even distantly related plant species.” Answer: This is another incorrect statement, perhaps due to a misinterpretation of the literature. Of the approximately 70 strains of Fusarium oxysporum, the host range is narrowly defined. As previously indicated, the forma specialies receives it’s definition from its host plant or closely related range of plants. They do not attack other plants—and do not mutate to attack other plants. Beyond the forma specialies, the micro-organism is further divided into races. Races are specific to individual cultivars (varieties) of the plant. These strict considerations are part of the reason that Fusarium oxysporum forma specialies Erythoxyli, Race EN4, was initially selected for its host-specificity to novogranatense and Erythoxylum Coca.
4. Mutagenesis Claim: “Fusarium oxysporum forma specialies Erythoxyli can change from one form to another.” Answer: This is wrong! Once again, the forma specialies receives it’s definition from its host plant or closely related range of plants. In this case, the plant taxonomy has been vigorously studied since 1910 and has been found to be highly stable. Due to the economic importance of Fusarium oxysporum wilt diseases, each of the principal agricultural strains has received extensive attention by the world’s best plant pathologists, and over decades. There are no documented cases of mutations extending the host range. The detailed genetic reasons for this specificity are complex, but compelling. The most profound in situ test of the mycoherbicide is its stable behavior even at the epidemic levels found in Peru. The ecological and environmental conditions of the Andean foothills in Peru and those in Colombia and Ecuador are essentially identical from a plant pathogenesis perspective. While Count Dracula can change easily from a human into a bat, this strain of Fusarium does not mutate!
5. Ecology Claim: “Anti-narcotics mycoherbicides will cause great ecological harm.” Answer: These claims are the weakest attacks, particularly egregious because they lack balance, perspective and scientific validation. As already noted, the pathogen selected already exists in South American countries and has reached epidemic levels in Peru during the 1990’s without creating any ecological issues. On the other hand, coca cultivation has devastated the ecology of the Upper Huallagua River Valley and sadly, is currently doing the same in many areas of Colombia.
A mycoherbicide would eliminate the slash and burn approach because it can be applied without concern (host–specificity) and can exist for decades. An attempt to clear treated forest land adjacent to coca growing areas would result in rapid kill of new coca seedlings and discourage all further coca expansion.
6. Claim: “Biocontrol advocates are biological bullies, trying to use strong-arm tactics to get smaller, weaker nations to use mycoherbicdes against their will.” Answer: The claim has validity. Some drug producing nations may voluntarily apply mycoherbicides on drug-producing plants. In many cases, sovereign governments are less than indirectly complicit in the illegal trafficking of drugs. They are not expected to respond to anything less than political pressure, if even to that. Unfortunately, many nations will countenance no curtailment of their cultivation of narcotic plants. It is a case where stronger nations may have to act covertly or unilaterally.
A Model Answer For The Future: And that brings us back to The African Contribution. It is a curious fact that while a contentious debate is building over the use of one Fusarium oxysporum strain to eradicate approximately 200,000 hectares of coca in South America, in sub- Saharan Africa another strain of Fusarium oxysporum is being field tested to eradicate up to 50,000,000 hectares of Striga. (250 x) Better known as ‘witch weed’ Striga invades fields of cereal crops such as sorghum, depleting the nutrients and decimating the crop. Farmers are forced to give up, to move to the cities, increasing the problems of urbanization, overcrowding and disease, while at the same time having to turn to expensive imported grains for sustenance. Researchers at McGill University in Montreal have recently achieved major successes in the control of Striga and have received international recognition for their contributions. From a scientific standpoint there is no significant technical difference in the two initiatives, Certainly the overall risk associated with coca is far less, both because of the relatively smaller areas to be treated and the significantly greater body of data that has been acquired. Nonetheless, the Striga work is proceeding along an established methodological approach for testing and qualification of a new mycoherbicide. It has political and policy support and should contribute significantly to the global challenges of sustainable food in the new Millennium. Is the coca research any less valuable? Will it receive comparable political and policy support to help eliminate the global scourge of drug use? Addendum: These are some of the facts. Once one considers the claims made above and their answers, and given the fact that the answers rely on fact rather than conjecture, who is to blame for the shoddy reporting that has so far characterized the preponderance of media coverage? Is it the fault of the media for not having done proper homework, of shooting from the hip? Or, is it the fault of advocates for not having provided the media with all the necessary background? Is it possible that doing reliable homework is no longer a prerequisite to maintaining professional journalistic standards, merely a nuisance to be avoided in light of busy travel schedules? Hopefully, science writing in the future will show a greater respect for the validity of authenticated research. Obviously, we feel the media has a moral obligation to be better acquainted with the facts. One must also bear in mind that reporting on this type of biotech research and the persons who do it is not always news best entrusted to the general public. Perhaps it need not be reported at all? It is, due to nature of the problem, a media sensitive issue, one that when reported, makes mature, responsible journalism even more obligatory. The researchers are putting much more on the line than their detractors, and much more than their professional reputations.
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