Cockroaches evolving? According to a new research, cockroaches are evolving and becoming increasingly difficult to eliminate because they quickly develop cross-resistance to the best insecticides used by the exterminators, warn US entomologists.
These insects pose a real threat to human health. They carry dozens of types of bacteria, such as E. coli and Salmonella, that can be transmitted to humans. In addition, their excrement and remains of moults can trigger allergies and asthma, but also cause problems in some people, such as gastro.
According to Michael Scharf and his colleagues at Purdue University, the problem is particularly acute in urban areas and in housing for low-income or state-subsidized people, where actions to effectively combat these insect pests are not always taken.
Cockroaches develop resistance to several classes of insecticides at a time, making the fight against these insects almost impossible with only chemicals.Michael Scharf, entomologist at Purdue University
Each class of insecticide acts in a different way to kill cockroaches. Exterminators often prepare a mixture of several classes of insecticides. Thus, if a small percentage of insects resist a class, insecticides of other classes will eliminate them.
US researchers tested these methods in multi-unit buildings in Indiana and Illinois for six months.
In a first treatment, three insecticides of different classes were used alternately each month for three months and again. In a second, they used a mixture of two insecticides of different classes for six months. And in the third, they chose an insecticide to which the cockroaches had low initial resistance and used it all the time.
In each location, cockroaches were captured before the study and tested in the laboratory to determine the most effective insecticides for each treatment, allowing scientists to achieve the best results.
“If you have the opportunity to test cockroaches before and choose an insecticide that has low resistance, it increases the chances,” says Michael Scharf. “But even there, we had trouble controlling the populations. “
Using three insecticides, the researchers managed to contain the cockroach populations for a period of six months, but they failed to reduce them.
In addition, the mixture of two insecticides did not work and populations flourished.
In one experiment with a single insecticide, Scharf and his colleagues found that there was little resistance to the insecticide chosen, and they were able to virtually eliminate the insect population. In another, there was about 10% resistance initially, and populations eventually increased.
Subsequent laboratory tests on the remaining cockroaches showed that cross-resistance probably played an important role. A certain percentage of cockroaches showed resistance to a class of pesticides. In fact, those who survived treatment and their offspring would be essentially immune to this insecticide in the future.
In addition, they also acquired resistance to other classes of insecticides, even if they had not been exposed and had no resistance before.
We have seen the resistance quadruple or sixfold in a single generation. We absolutely did not imagine that such a thing could happen so quickly.Michael Scharf, entomologist at Purdue University
Females have a three-month breeding cycle during which they can have up to 50 pups. However, if a small percentage of cockroaches are resistant to an insecticide and cross resistance develops, a population eliminated by a single treatment could explode again in a few months.
These researchers, whose work is published in Scientific Reports, say that only an integrated approach to pest control can overcome a cockroach problem. They recommend combining chemical treatments with traps, vacuum cleaners, but also improved sanitation facilities.
“These techniques are often more expensive than using insecticides, but if they do not control or eliminate a population, then money is wasted,” says Scharf.
“Combining several methods will soon be the only effective way to eliminate cockroaches,” concludes Michael Scharf.
Types of cockroaches
There are more than 4,500 types of cockroaches in the world. And while this number is high, the good news is that you only have to worry about five or six different kinds of cockroaches, depending on where you live.
Most cockroach species rarely invade homes, including the western wood cockroach and the brown hooded cockroach that prefers to live outdoors.
But the news is not all good. These few cockroach species that want to move in with you can easily become a nightmare for any homeowner.
Consider that for every cockroach you can see, there is a good chance that there are dozens, if not hundreds, in your home that you can not see. And while all cockroaches may seem to disperse when you turn on the lights, knowing how to differentiate between the most common types of cockroaches in your home will help you choose the most effective pest control methods to stop them.
General appearance of all types of cockroaches
First, be certain that you are dealing with cockroaches. Cockroaches can be confused with other insects such as grasshoppers, beetles or crickets.
Cockroaches have a broad, flattened body, with long antennae and long hind legs. Each of their six legs has tiny sensory hairs. Adult cockroaches have wings that fold flat on their backs, but all cockroaches can not fly.
Most roaches are brown or black and can range from 0.07 to 3 inches in length, depending on the species.
One of the most distinctive features of a cockroach is the shield located directly behind the head. If you see a cockroach in your house, chances are it’s a German cockroach or a brown-banded cockroach. They are the two most often unwelcome inhabitants of houses, buildings and structures.
The German cockroach is the most common of all types of cockroaches found in homes. Their high-speed breeding ability makes them a direct threat to your family and home. It only takes one single female to enter your home. Between her and her offspring, more than 30,000 cockroaches can be produced in a year, but many of them will not live very long. Those who survive are more than enough to cause disease and disgust.
Each German cockroach eggshell can hatch between 20 and 40 cockroaches, and unlike other cockroaches, the adult female carries the eggs with her until they are ready to hatch. This makes them extremely persistent and difficult to eliminate.
- Length: 0.6 inches; smaller than American or Asian cockroaches.
- Color: light brown
- Distinctive features: two dark and parallel bands on the “pronotum”, from head to wings.
- Preferred Locations: areas near water sources with food, such as kitchens, storage areas and bathrooms.
- Flight: hardly, but can slip in the blink of an eye.
- Entry: usually carried by visitors, parcels, clothes, handbags, used furniture, etc. but also easily spread through the walls of multi-family units
While German cockroaches and brown-baded roaches may live in the same house, they seldom hide in the same places. Brown-banded cockroaches prefer warmer and drier places, especially in height and inside your electronics, TVs, refrigerators, etc. They tend to stay away from water.
- Length: 0.5 inches; smaller than American or Asian cockroaches.
- Color: males are dark brown at the base and golden brown towards the tips of the wings; females have reddish-brown wings and a dark brown body.
- Distinctive features: Males and females have two light yellow bands on the wings, abdomen and sides of the pronotum.
- Preferred location: warm and dry indoor spaces, ceilings, behind frames and clocks, hollowed out wood and clutter, inside electrical appliances.
- Flight ability: Only males can fly, more likely to jump.
- Entry: as the German cockroach, usually carried by visitors, packages, clothes, handbags, used furniture, etc. and easily spread through the walls of multi-family dwellings.
Although it is not the most common cockroach in homes, the American cockroach is the largest. They can survive for up to two years, much longer than other types of cockroaches. These cockroaches are more commonly known as “palmetto bugs” and finding them can be particularly alarming.
- Length: 1 to 3 inches; the biggest
- Color: brown to reddish-brown
- Distinctive features: light yellow edges on the pronotum
- Preferred Locations: prefers the outdoors but likes hot and humid places, sewers, drains, kitchens, laundry rooms, basements and bathrooms.
- Flight ability: adult males and females can fly.
- Entrance: may enter under doors, basement windows, garages or sewage system.
Smoky- brown cockroaches
The smoky brown cockroach dehydrates very quickly, so you will see these types of cockroaches in damp places. They are excellent aviators and extremely nocturnal, although they are attracted by the light and will enter the houses when they see it.
- Length: 1.5 inches; a little smaller than the American cockroach.
- Color: a dark mahogany coat, pronotum black.
- Distinctive features: wings longer than the body.
- Preferred Locations: gutters, attics and crawl spaces
- Flight ability: adult males and females can fly.
- Entrance: plumbing, vents, trees, vegetation, shrubs, etc.
More commonly known as “water bugs”, the eastern cockroach lives in the dark and likes damp places that are out of sight and damage caused by humans. It is therefore more difficult to get rid of it without the help of pest control professionals, as pesticides may be washed away.
- Length: 1.25 inches
- Color: dark brown or glossy black.
- Distinctive features: shiny appearance, male wings shorter than the body, underdeveloped female wings.
- Preferred Places: Areas containing tonnes of moisture, decomposing organic matter, sewers, wet basements, etc.
- Flight ability: none
- Entrance: may enter under doors, basement windows, garages or sewage system.
No matter what types of cockroaches you have, you do not want them in your home or around your family. Cockroaches can transmit diseases when they are contaminated by crawling on floors, in drainage pipes or in other low places where they are usually move.
A few minutes later, you can see the same roaches roaming the clean dishes or the foods you have prepared. The best way to make sure your home is free of cockroaches is to call a pest control professional and get a free pest assessment.
How to kill cockroaches
A simple but effective mixture. Baking soda and sugar are able to effectively help kill roaches, and you will be able to see a rapid decline in the growth of these pests. You need to know where the cockroaches are hiding, so it’s important to note where you’ve seen these pests before planting the bait so they can eat it.
Here’s what you’ll need to get started:
- Baking soda
- A bowl or a cup
Baking soda is not poisonous in the same way as boric acid, and it will begin to mix with the cockroach’s stomach acid, causing it to die over time.
You will need to mix equal parts of baking soda with equal parts of sugar for this solution to be effective. Now all you have to do is sprinkle this mixture in places where you have seen the cockroaches. You will need to leave this bait and repeat the action as often as possible to make sure there is enough to kill cockroaches. Sugar is not the deadly part of the mix, but it will act to attract the cockroaches.
Boric acid can be bought in stores or online, and is one of the best killers of cockroaches, ants and a variety of other pests. This acid has proven effective in killing cockroaches, and it is one of the most commonly used remedies.
But since boric acid is not safe for humans, you should keep it out of the reach of children and pets. Indeed, it is a poison, and a long-term exposure can make you sick. Ingesting boric acid will also cause poisoning that can be serious.
Cockroaches will die if they come in contact with this acid, but there are a few things you should consider when sprinkling boric acid in your home:
- Only a slight dusting is necessary (too much, and it will be inefficient)
- Boric acid is not effective when wet
The goal is to keep cockroaches running through the boric acid powder, which is difficult if the cockroaches are in tight corners or under cabinets. Once you have placed the acid, cockroaches will have it on their antennae, paws and body. During grooming, the acid will be ingested, resulting in the death of the cockroach.
Fabric softener spray
You can also make a home remedy to get rid of cockroaches. Fabric softener can kill cockroaches, but it can not only be placed on the floor in the hope that the job will be done automatically. Instead, you need to spray it and actively spray the cockroaches you see outside and in your home.
The solution will be rather thick, so keep this in mind when you are going to spray
When you see cockroaches, sprinkle them with the solution. If you see a cockroach squatting behind a piece of furniture, you can often spray it more easily than if you tried to walk on it, for example.
The cockroaches breathe through their skin, so that when the thick spray arrives on the roach, it will choke it. This is one of the home remedies for roaches that works best if there is a massive infestation in your home. Dishwashing liquids can also be used in place of the fabric softener. However, it is sometimes less effective.
You may be against killing animals, even if they are harmful cockroaches. Maybe you do not want to kill them, but you just want to keep them outside your house. Bay leaves are a natural repellent for roaches. This is ideal because these insects simply hate their smell.
Another major benefit is that bay leaves are not toxic to humans, so you will not have to worry about where you place them. To be more effective, it is necessary to crush the leaves.