Pesticides are used to kill pests (insects, bacteria, rodents, fungi and weeds) and are essential to meet the high global demand for food. Unfortunately, its extensive use can cause environmental problems. That is why it is necessary to reduce it. But what if there was a more effective and environmentally friendly alternative?
A group of researchers from the Advanced Porous Materials Unit of the IMDEA Energy Foundation and the University of Granada have developed a new material with application in agriculture based on two active ingredients: the herbicide of natural origin glufosinate and copper, with antimicrobial activity
Agrochemicals: essential and harmful
Agrochemicals (basically fertilizers and pesticides) are essential in agriculture. Although they have been used for many years, their excessive use is deteriorating the quality of ecosystems. Thus, agrochemicals affect our health and can lead to the development of new resistant pests.
Its toxicity is manifested through biochemical and functional agents in the nervous system. Furthermore, although it is not always easy to identify them, there is evidence linking long-term exposure to some agrochemicals with chronic diseases. Some examples are skin, respiratory, liver and kidney disorders, cancer development and fertility problems. A recent study from the University of Granada links exposure to pesticides with a premature start to puberty.
On the other hand, pesticides can cause the development of new resistant pests. Through genetic variation, pests naturally evolve and become resistant to the products used to kill them.
Also, taking into account that the world population does not stop growing, will we be able to increase the demand for food in a sustainable way if we continue to use so many pesticides?
more respectful pesticides
In recent years, different alternatives have been proposed to reduce the amount of agrochemicals in crop fields. Specifically, the development of new materials that are capable of:
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improve the solubility and stability of agrochemicals,
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release them in a controlled and directed manner,
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improve its adhesion and availability in the plant.
In this context, a new class of porous materials known as porous coordination polymers or MOFs stands out. These materials allow the efficient incorporation of active molecules and their subsequent controlled release. Compared with classic porous materials (carbons, silica), MOFs present a series of advantages for agriculture:
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They are very porous, so they can store a large amount of pesticides.
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They are formed from pieces (molecules, metals), such as a chemist lego that may be active against pests. In this way, by joining several pieces, a material with multiple actions (antibacterial, fungicidal, pesticide, with nutrients, etc.) can be obtained.
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They can be modified to improve your activity. For example, so that they stick to the plant.
AgroMOF: the LEGO of agrochemicals
The material we have developed is called AgroMOF. This is the first time that a MOF has been synthesized using agrochemical compounds (in this case, glufosinate and copper) as precursors.
Pesticides are often sprayed in the form of an aqueous solution or in suspension on the fields. The first step was to study the stability of this new material in water. We check that it is stable in water for at least 5 days.
Subsequently, we tested the activity of its different pieces: the ability of copper to eliminate bacteria and the herbicidal effect of glufosinate. Its activity was verified against two types of bacteria that cause infections in plants and the radish weed, an invasive species in berry and vine crops. This new material is effective against both types of bacteria, even improving the effect of their individual precursors (glufosinate and copper).
On the other hand, its herbicidal activity also improves. This material is capable of drying radish in 8 days, whereas glufosinate alone cannot.
Finally, we verified that this new material is not toxic against crop plants such as the black currant. These results demonstrate its efficacy and selectivity in the treatment of berry crops.
From our study we can conclude that the manufacture of AgroMOF based on herbicidal compounds and antibacterial compounds is a promising strategy to obtain agrochemicals with several combined functions, allowing to improve their activity with a better dose. This work opens new avenues in the safe and efficient application of these materials in agriculture.
