written by Roua Eltayeib*
One of the most notorious pests of any garden is the aphid. The aphid in some ways is like plant lice in that they reproduce quickly and they are unwelcome little creatures that drive the gardener nuts. However, I find the aphid to be more similar to an insect that we humans truly dislike: the mosquito. Both these pests do very similar things and act in similar ways especially when it comes to how they fill their appetite.
One major similarity between these two creatures is how they get their food. Mosquitoes have an appetite for the blood of mammals, like us. They land on skin and pierce it with their proboscis, which is a very sharp and thin tube that you will not likely at all feel being inserted. Aphids, on the other hand, definitely are not after blood, but are after something equivalent to that. They love sugar and they are able to satisfy their appetite with the sweet taste of plant (phloem) sap. Like to the mosquito, the aphid pierces and sucks the plant. It uses a mouth-part known as a long stylet, which contains a saliva and food canal. It uses it to suck out the sap from the phloem of the plant.
The technique of piercing for both insects serves another purpose as well. Both insects are mechanically engineered to counteract the defenses that organisms put up. The mosquito and the aphid both pierce in, but before taking in a delicious meal, they inject their saliva. When a mosquito injects its saliva, the proteins (anticoagulants) contained in the saliva prevent the blood from clotting. This insures that the mosquito can keep sucking until it is completely satisfied. A similar thing happens with the aphid. In the aphid’s case, it uses its saliva not to stop the plant’s defenses, but rather to overcome the plant’s protein defense response. When damage is done to the phloem cell of a plant, the plant sends out calcium to block the damage. This is similar to our bodies’ way of defenses. The aphid, able to take care of the defenses of the plant, can suck the sap in peace.
Another big similarity between these two insects is that they can quite easily bring harm to the organism. Because both these insects both take from the organism and inject, they can spread diseases faster than you know. As you probably already know, one of the diseases that are spread quickly through mosquitoes is malaria. Mosquitoes are able to carry the disease in the blood they ingest and easily inject the disease during their next meal. In the same way, aphids are harmful to plants because they can so easily spread viral diseases. They take in sap and inject their saliva. In both situations, the host really has no way of defending itself.
However, there are steps to prevent these aphids from harming your beloved garden. Aphids tend to harm fruit and vegetable plants. By planting flowers nearby, like sunflowers, daisies, and marigolds, you can attract insects that kill aphids and prevent them from doing any harm. Dosing the plants with water also helps, knocking the aphids right off their feet. Aphids are annoying pests, but they can be prevented from doing harm. Those pesky mosquitoes however, you might just need some bug repellent to solve that issue!
*Roua is a Sprout Farms summer intern and graduate of the Brooklyn Latin School.