Article 3-4
Pesticides
by Erwin Rosario, Atami, Holland
- Pyrethrum:
Pyrethrum is made from the flowers of an African type of chrysanthemum. Its
Latin name is Chrysanthemum Cinerariaefolium. It is very poisonous to
insects and bees, because it works on their central and peripheral nerve
system. This causes the impulse transference to be disrupted. After
convulsions death will follow. An insect that is contaminated by the toxin
will drop dead on the spot. If the concentration is high enough, the insects
will be dead instantly. Pyrethrum is less poisonous to flies and
cockroaches. Fish on the other hand are very susceptible to Pyrethrum. To
mammals it is less harmful. The deadly dose for humans lies around 100
grams. Pyrethrum can however also cause allergic reactions, like rash, to
those people sensitive to it. Pyrethrum is mostly grown in Kenya. At
daylight Pyrethrum disintegrates into innocent inactive compounds, within a
few hours.
Because Pyrethrum decomposes quickly, synthetic compounds are sometimes
added to the natural product. For instance Pyrethroids and Piperonyl
Butoxide. Pyrethroids are synthetic compounds made by the chemical industry.
Pyrethroids cannot be decomposed as well as the natural Pyrethrum. Piperonyl
Butoxide is not a pesticide, but a booster (synergidae) of Pyrethrum. It
inhibits demolition and therefore increases the effect of Pyrethrum. It is
however also a synthetic compound. So by far, not all products, which are
named Pyrethrum, are in fact "natural" or
"environment-friendly".
- Nematocides kills little worms and larva
- 1988 yield per square meter:
Tomatoes 34 Kg; 1998=63 kg
1988 yield per square meter
Paprika 20 Kg; 1998=34 Kg
1988 yield per square meter
strawberry 3.5 Kg; 1998=4.5 Kg
- Reasons why not to use pesticides:
- Environmental problems
- Food Contamination
- Safety of workers
- Inadequate production methods in third world countries
- Suicide
- Explication of nerve gas:
Nerve cells (neurons) contain threadlike ends (axons). The nerve impulses go
from the central nerve system (brains, spinal marrow) via the neurons to the
different organs and muscles. When an axon ends, the electronic message
needs to be transmitted, for instance to the axon of another nerve cell or
muscular cell. The gap that needs to be narrowed (around 20 nanometers: nano
= millionth) is called the synapse.
Stimulus transfer within the synapse occurs by using biochemical
substances. When a stimulus reaches the end of an axon, a small amount of
acetylchline is released and then stored inside very small blisters at the
very end of the nerve vessel. The released acetylcholine diffuses
(diffusion) to the receptor places of for instance a neighboring muscle
vessel membrane. After the impulse has been transmitted in this manner, the
receptor places are released again.
This occurs under the influence of enzyme cholinesterase, which through
the molecular bond of acetylcholine is divided into acetic acid and chorine.
These small compounds can no longer bind to the receptor places.
An important group of insecticides are the phosphor ethers. The effect of
phosphoric insecticides (parathion, Malathion, dichlorinefox and demeton) is
based on the blockade of the enzyme cholinesterase. Because of the blockade
an overdose of acetylcholine inside the synapse is created. The consequence
is an "over stimulus" of the receptor places and uncontrollable
muscle contractions and muscles paralysis can occur. With insects this may
lead to paralysis of the respiratory muscles, which can lead to suffocation.
- When residues of synthetic pesticides (parathion included) are heated, a
great risk is carried. At the combustion of chemical residues of pesticides,
dioxins can be released. These are the most poisonous compounds known up to
now. These dioxins are also released when lighting a cigarette or other
stimulants, which have been treated with synthetic pesticides. They are very
harmful to mankind.
- The use of pesticides has caused numerous problems for the environment.
There is no way to keep pesticides out of water sources. This contamination
hurts the ecosystem around the water, the wildlife, and the humans who drink
the water. Also pesticides cause soil degradation. If we continue to use
pesticides, the soil will become less effective and crop yields will begin
to drop. Furthermore pesticides add to the depletion of the ozone layer and
add to the greenhouse effect( for example methyl bromide).
- When we introduce foreign chemicals into our food, we run the risk of
contamination. The food grown using pesticides contains chemical residues.
Although these chemicals are constructed to have no adverse effects on
humans, it is impossible to know the long term effects of pesticides
residues. On a more alarming level, 31 people died from pesticides
contaminated bread at a party in the Sudan. This contamination was caused by
improper application of pesticides and is very common in third world
countries which lack the same application tools.
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