Because they dominate all terrestrial environments that support human life, insects are usually our most important competitors for food, fiber, and other natural resources. The harmful direct impact of insects on agricultural food production by chewing the leaves of crop plants, sucking out plant juices.
Harmful Impact of Insects:
Insects feed on natural fibers, destroy wooden building materials, ruin stored grain, and accelerate the process of decay. They also have a big effect on the health of people and pets by being annoying, biting or stinging them, and spreading disease.
The economic impact of insects is measured not only by the market value of products they destroy and the cost of damage they inflict, but also by the money and resources expended on prevention and control of pest outbreaks.
Even though it’s hard to put a dollar value on these losses, especially when they affect people’s health and well-being, economists agree that insects eat or damage about 10% of the gross national product in large, industrialized countries and up to 25% of the gross national product in some developing countries.
These and other aspects of economic entomology will be our main emphasis in the final section of this course, when we focus entirely on insect pests and the tactics used to control them.
But despite the tremendous economic losses they may cause, it is not entirely fair to cast the members of Class Insecta as villains who rob us of our food and livelihoods. They are also cherished allies on whom we depend to keep the natural environment clean and productive.
It has shaped human cultures and civilizations in countless ways. They supply unique natural products; they regulate the population densities of many potential pest species; they dispose of our wastes; bury the dead; and recycle organic nutrients.
Indeed, we seldom stop to consider what life would be like without insects and how much we depend on them for our very survival. To paraphrase William Shakespeare, “The evil that insects do lives after them; the good is often interred with their exoskeletons.”
The Brown Marmorated Stink Bug
It is a pest of many different fruit trees and plants. The Brown Marmorated Stink Bug was accidentally brought to North America from Asia.
It made its way to the coast and has been spreading from there. They are known to damage fruit only in appearance (not its flavor), rendering the fruit less likely to sell at market.
The Brown Marmorated Stink Bug uses its proboscis to poke a hole through the skin of a piece of fruit that is still growing on the tree. It sucks out the fruit’s juices. The depletion of juice coupled with the piercing of the fruit’s skin results in a dimple. You can read more about how do you get rid of stink bugs at xvola.com.
This permanent depression deforms the fruit as it grows to picking size. A series of these bites on one apple can cause the fruit to look quite deformed and unappealing at the market.
Such devalued fruits can still be processed into pies and other edibles that are not as profitable.
The color of the Brown Marmorated Stink Bug keeps them effectively camouflaged among branches and dead leaves. The brown body is covered in small black freckles.
Both nymphs and adults feed off of tree leaves and hanging fruit. The nymph (juvenile) looks nothing like the adult. It is round like a ladybug and red and black. Three thick, black dashes cross its red abdomen.
Insects as agricultural pests.
Negative impacts from insects are a significant threat to agriculture. Harmful insect pests include caterpillars, grasshoppers, and locusts, which eat the leaves, seeds, and fruits of crops.
At times, locusts can form massive plagues of several million, which can cause widespread damage to crops and lead to famine events. Other insects, including aphids, thrips, and weevils, suck the sap from plants, which can affect plant growth and development and make plants more susceptible to disease.
The harmful effects of pests also include carrying and spreading plant diseases that impact animal life.
You can get rid of insect pests by spraying them with pesticides, using smoke, putting irritating chemicals like capsicum on them, or encouraging natural predators to get rid of them.
Damage to growing crops
Insects are responsible for two major kinds of damage to growing crops. First is direct injury done to the plant by the feeding insect, which eats leaves or burrows in stems, fruit, or roots.
There are hundreds of pest species of this type, both in larvae and adults, among orthopterans, homopterans, heteropterans, coleopterans, lepidopterans, and dipterans.
The second type is indirect damage, in which the insect itself does little or no harm but transmits a bacterial, viral, or fungal infection into a crop. Sugar beet and potato viruses, which are spread from plant to plant by aphids, are a good example.
Although most insects grow and multiply in the crops they damage, certain grasshoppers are well-known exceptions. They can exist in a relatively harmless solitary phase for a number of years, during which time their numbers may increase. You may read more at projects.ncsu.edu
They then enter a gregarious phase, forming gigantic migratory swarms, which are transported by winds or flight for hundreds or thousands of miles.
These swarms may completely destroy crops in an invaded region. The desert locust (Schistocerca gregaria) and migratory locust (Locusta migratoria) are two examples of this type of life cycle.
Some insects are dangerous to humans because they use you as a food source. Biting flies, for example, bite big chunks of our skin.
Ouch! Other insects like the kissing bug, tsetse fly, mosquitoes, or ticks use us for snacks and pass diseases to us that can cause very serious health effects. Many of these bugs are not dangerous in themselves, but the diseases they carry can create serious health problems around the world.
For example, kissing bugs may sound sweet, but the Chagas Disease that you can get from their ‘kiss’ is not.
Mosquitoes are the vampires of the insect world because they suck our blood, but that’s not the real reason they’re dangerous. The bite of certain kinds of mosquitoes can carry many different diseases, including a very dangerous parasite that causes malaria.
As a result, the mosquito is the most dangerous insect because it causes the most harm and even death.
Ticks are another common example of a blood-loving insect. Hikers or outdoor enthusiasts pick up ticks, and these ticks burrow themselves into their skin.
Ticks like the other bugs we’ve mentioned, are harmless. But they carry a parasite that causes Lyme’s disease, which can cause things like joint pain and sleepiness. Tsetse flies, found in Africa, also cause sleepiness. They carry another parasite responsible for the deadly sleeping sickness.