The Weeds In The Willows

This paper was written with the sole intention of informing consumers about the products they may currently be buying.  Hopefully with enough demand from consumers industries will supply safer and more sustainable products.

Humans have been harvesting plants since the beginning of our earliest civilizations. Our ancestors noticed that some of these food-producing plants were not suitable for harvest due to a number of factors.  Some were eaten by insects and/or other species of animals, while other plants succumbed to plant diseases.  However, the obstacle that caused the most damage both then and now is weeds.  Weeds take up space and nutrients from the chosen crop. Additionally, some weeds poison crops, which can cause some or most of the wanted plants to die. Hence, In 2019 alone, weeds cost farmers over $26 billion a year in yield reduction and an additional $7 billion in herbicides (R. Baucom, S 2019).

Historically, farmers managed weeds by crop rotation, appropriate tillage, and fallow systems (P. Kudsk et al 2003).  These practices were labor-intensive.  The invention of herbicides gave farmers an easy and effective tool to combat weeds. Wartime research during World War II led to the creation and subsequent widespread use of the deadly herbicides MCPA and 2,4-D  (P. Kudsk et al 2003). Subsequently, in the 1950’s a new family of herbicide compounds was discovered and marketed widely to farmers.  Synthetic herbicides continued to be quite popular until the late 1970’s.

🌾 Weeds Are Evolving to Adapt to Synthetic Herbicides 🌾 

Historic and current use of herbicides has resulted in alarming changes to ecosystems found in agricultural areas. Some plants affected by exposure to herbicides have begun to evolve and have adapted to herbicide-resistant varieties (R. Baucom, S 2019). This phenomenon was first identified in Hawaii sugarcane plantations in 1957 (R. Baucom, S 2019). Subsequently, It has been found in at least 174 other plant species, including soybeans, maize, canola, and cotton (M. Owen and Zelaya, A. 2005). As these plants have adapted, the common approach has been to increase the toxicity and amount of synthetic herbicides. The environmental impacts are escalating swiftly. As a result, there has been increased runoff of herbicides into soils and waterways. (AHC Van Bruggen et al 2021).  This in turn directly affects the reproductive stages of native plants, which can reduce species diversity (AHC Van Bruggen et al 2021).

🐠Consequences of Using Synthetic Herbicides To Control Weeds🐠

Furthermore, the cumulative impact of repeated herbicide applications can persist in the environment for decades  (AHC Van Bruggen et al 2021). Resulting in herbicide contamination that affects both plants and animals.  For example,  in fish, herbicide residues tend to accumulate in lipid-rich tissues such as the liver, kidneys, and muscles.  These toxins affect growth, longevity, reproduction, and behavior (A. Giglio & M. Vommaro 2022).  

Another side effect of chemical herbicides is that they pollute the environment.  They kill numerous species of fungi and protozoa.  Beneficial bacteria, including those that consume other microorganisms, were also eliminated. Herbicides can increase disease-causing organisms.  Herbicides spare them and then kill organisms that would naturally control their population.  (PC Latha and H. Goal 2010).  Plus, herbicides cause the soil to be less fertile (PC Latha and H. Goal 2010).

🍾 Some Growers Are Using Vinegar To Control Weeds 🍾

Given all the problems caused by synthetic herbicides, some growers and homeowners have been utilizing natural herbicides.  The effectiveness of natural herbicides depends on a few factors including and not limited to the stage of development of the weed.  In the germination stage, vinegar or more specifically, acetic acid (the active ingredient in vinegar) is highly effective.  Using acidic acid directly on the weeds does not inhibit the root length or leaf surface area of non-target species (H. Pujisiswanto et al 2013).

However, acetic acid loses its potency once the weeds have germinated and started to grow. Organic herbicides are most effective when weeds are young and actively growing.  Organic herbicides include citric acid, clove oil, d-limonene, cinnamon, and lemongrass (T. Lanini 2010).  Among the options listed, cinnamon and clove oil were found most effective at eliminating weeds (T. Lanini 2010).

🌲Another Natural Approach To Combat Weeds Is Natural Oils 🌲

 Bioherbicides are another type of natural herbicide.  Bioherbicides utilize microorganisms as thier active ingredients. These substances are based on phototoxins, which prevent the germination and growth of weeds.  Microorganisms derived from pine and manuka oil are the most highly effective bioherbicides  (V. Maria et al. 2020). Additionally, they have high selectivity, meaning they have little to no side effects on non-target organisms.  They do not leave residues or cause resistance in plants (V. Maria et al. 2020).  Lastly, there is a promising group of natural herbicides called phytopathogenic fungi. This fungus can produce toxic substances.  It penetrates leaves, disintegrates cellular structure, and induces the production of necrotic lesions (V. Maria et al. 2020).  As a result, it can kill fully grown weeds, and it has no effect on non-target species.

🌎 The Future Of Weed Control Will Be Natural 🌎 

The answer to converting to natural herbicides is complex. Synthetic herbicides are losing their potency so a natural solution is imminent.  Each natural herbicide has its advantages and disadvantages. Currently, growers can use natural herbicides to combat target weeds at each stage of growth.  There are other factors that can affect their potency, including temperature and soil Ph.  So growers need to figure out the combination of natural herbicides that works best for each particular crop.  With enough dedication and hard work, the world can save itself from synthetic herbicides and create a more sustainable future.