What are pesticides?
The spreading use of pesticides has been very controversial for these past decades. It is indeed one of the most concerning issues in the agriculture industry, especially in California. This US state grows a whopping 54% of the citrus fruits produced for the United States (Source: Citrus Fruits Summary) total citrus production. These citrus fruits include oranges, lemons, mandarins, and grapefruits. So, how is pesticide issue connected with yummy citrus fruits grown in sunny California? Well, citrus fruits like other fruits that are grown need protection from weed trees and excessive grass. Weed trees are unwanted trees that you didn't grew, however, these parasitic plants can grown anywhere and anytime near your plants. Think of this plant as the guest in your family who always makes surprise visits (source: Washington State University). Weeds and excessive grass near a citrus tree makes it extremely competitive for the citrus trees to gather nutrition since all of the vegetation would be fighting for the same space, water, sunlight, and for other minerals that are critical to its growth.
Let's stop beating around the bush (pun intended), and understand pesticides. These substances target "pests and disease carriers" and are used in agriculture to "control weeds, insect infestation, and diseases" (Source: https://www.epa.gov/). There are many types of pesticides that target a specific species, such as insecticides, herbicides, and fungicides (source: EPA | Types of Possible Ingredients)
How are they made?
From 1930-1950s, pesticides were heavily used since there was the Great Depression which caused a massive downhill for country's economy and staged global poverty. As a result, farmers with no law restraining them to use pesticides, started using it incessantly. This overuse heightened its environmental impact. The pesticide products "contain at least one active ingridient" and an inert ingredient. The inert ingredients could be chemicals, compounds, or an artificially created substance (source: https://www.epa.gov).
One of the most common example is Dichlorodiphenyltrichloroethane (DDT), an insecticide, which was banned during 1972. This insecticide aided farmers greatly when maintaining a livestock, dairy farms, clean supply of water, and growing crops. However, its overconsumption posed detrimental consequences on the buyers of the farm's produce since there were higher levels of residues remaining on the food. As a result, people had symptoms of seizures, and vomiting from the DDT protected food .
Connecting the context and our knowledge to the present, many Californian farmers use the Neonicotinoid, an insecticide that's used on honeybees. Not to mention, the UN Food and Agricultural Association stated that "71 out of 100 crops that provide 90 percent of human food are pollinated by bees." This insecticide is absorbed by the plant and further damages the pollinators in our ecosystem.
Clearly, these insecticides are the cause of higher mortality rates in the honey bees population. Considering that the European Union (EU) banned Neonicotinoid, it poses a question of its existence in the US. The neonicotinoids have similar chemical structure as nicotine and are regarded as systemic insecticides (pesticides that can be absorbed entirely by the plants’ roots). This is important since another use of neonicotinoids are the seed coatings. Seed coatings help the seed stay safe from underground organisms such as fungi. In addition, seed coatings’ general use is in corn, cotton, and canola.
How do these insecticides affect pollinators such as honey bees?
According to Frontiers Research, these insecticides are agonists (that initiate chemical responses and receptors) of nicotinic acetylcholine receptors (nAChR). The effect of nAChR (present in the Central Nervous System) is that it reduces the olfaction (sense of smell) among honey bees, memory, and learning (source: Jones et al., 2006). Moreover, neonicotinoids are more toxic during winter time and lower temperatures since honey bees are ectotherms (organisms that rely on the environment for proper body functioning). Many processes that occur in their Central Nervous System are vulnerable to such toxicity and further decrease their survival rate.
Why are bees important in agriculture and ecosystems?
Honey Bees (Apis mellifera) are unofficially recognized as 'crop pollinators.' Pollination is the transfer of pollen from one crop to another. And this step is incredibly necessary for plant reproduction as pollen transferred from the flower's male part (anthers) rubs on a female plant's stigma through the vectors (such as honeybees, animals, birds, butterflies, and animals which are in close contact to flowers). This initiates the creation of seeds which could be further used to grow fruits, and vegetables (source: https://www.fs.fed.us)
Revisiting the issue of killing wild honeybees or bees in general through an insecticide would not only prevent plant reproduction but it would also breed disruption in the ecosystem as pollination will be decreased. As a result, 80% of our crops consumed by us are aided by pollinators and further won’t survive if there aren’t any bees (source: USDA | Why is Pollination Important?)
As the scientists research for ways to lessen the impact of insecticides on non-target species, you are bestowed upon the hopes of finding a better solution to help save the bees population.
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