Bio-Fungicides
Bio-fungicides are used in remediation of the diseases that impact crops. Fungal pathogens when controlled through the use of highly toxic chemicals impact the beneficial bacteria adversely. Nature cannot tolerate this vacuum and will adapt negatively or insufficiently to combat disease. The longer the use of commercial chemical fungicides, or misuse, the more profound the problem. Aside from the benefits of fertile, active soil there are direct benefits drawn from the individual species of bacteria that would attack and combat the chemical effects of commercial fungicides.
Many plant pathologists feel that bacteria rather than fungi are better candidates for the development of commercial biological fungicides since they can be used without fear of harming beneficial organisms.
Bacillus thuringiensis is the most widely used microbial insecticide. Bacillus thuringiensis contains a poison which looks like a crystal. This poison (toxin) is called BT toxin. BT toxin kills lepidopterans such as cabbage worms, tent caterpillars, and gypsy moths; dipterans such as mosquitoes and black flies; and coleopterans such as Colorado potato beetles, and Japanese beetles. At least 412 preparations of Bacillus thuringiensis and the BT toxins are registered for sale in the United States. Baculovirus is another widely used strain to combat many caterpillars, moths, and flies. Although there are over 450 viruses found to kill insects, the most widely studied viruses are the Baculoviruses.
Bio-fungicides are generally preventive rather than curative. It is best to apply them early in the production cycle before the pathogen attacks. Early application gives the beneficial microbes, in the bio-fungicide, a chance to colonize, enabling them to out-compete and/or attack the pathogen successfully, defending the plant against disease. Biological fungicides differ from chemical fungicides in their modes of action. Chemical fungicides generally have two modes of action. The first is by contact, where the chemical product must come into direct contact with the pathogen. The second mode of action is systemic, where the plant absorbs the chemical. The pathogen is then negatively affected when it attacks the plant. Since biological fungicides are living organisms, they have modes of action that are distinct from those of chemicals. PureAg products contain microbes that are antagonistic and parasitic to pathogenic fungi. Quite literally, the beneficial microbes attack and feed off of the invading fungi. The beneficial microbes in other biological fungicides have broad spectrum properties, including the production of antibiotics and/or enzymes. These exudates adversely affect and essentially kill pathogenic fungi. In their weakened state, the pathogens are far more susceptible to the vegetative bacteria.
Our application strategy is to increase the population and activities of beneficial microbes on and around plant tissue. Using the analogy of a parking lot filled to capacity, any new arrivals (disease pathogens) will be unable to find open spaces, and therefore will be forced to “find somewhere else to park”. These synergistic results are possible when certain beneficial microbes weaken the pathogenic fungi’s resistance.
An example of this synergy is with the beneficial bacteria bacillus subtilis, which produces an antibiotic that creates “pinholes” in pathogenic fungi’s cell walls. In their weakened state, the fungi are easy prey for other bacteria. Another important consideration is whether or not the microbes are spore producing (“gram positive”). Because “gram negative” bacteria are always in a live, active state, they have a very short shelf-life and extremely specific storage requirements. When gram-positive bacteria are faced with unfavorable conditions, they enter a dormant/spore state. They become active again when the conditions for their survival are favorable.
A successful biological fungicide must also be formulated in a manner that favors both the activity and survival of the microbes it contains. PureAg products are a powder with no special handling or storage requirements, and a shelf life of more than two years. In a liquid form it is entrained in a bio-surfactant to effect surface tension and allow for immediate absorption and utilization. It is able to be used on a wide range of plants and be effective against a variety of disease pathogens. PureAg also exhibits residual (lasting effects) and offers other ancillary benefits that include, improved root growth and development. Unlike chemical fungicides, bio-fungicides are comprised of all-natural materials. They do not contain chemical salts and phytotoxicity is not a concern. It is safe.