Cockroaches are now hard to kill and it’s difficult to control using pesticides, according to studies funded by the USA scientists.
The University of Indiana spent months to eradicate German cockroaches (Blattella germanica L.), one of the common species in the US, Australia, and Europe.
They used different pesticide mixes, a mix of two insecticides sprayed monthly; and abamectin gel baits applied once a month in an area where the cockroaches had been tested and showed low resistance to abamectin.
And here we know why Cockroaches stay in filthy places ….
The abamectin gel baits succeeded in reducing the cockroach evolution. In another place where 10% of the cockroach population was resistant to the chemical, populations grew.
Cockroach populations in the building treated with the three pesticides remained flat, and populations in the building treated with the mixed spray “flourished”.
Populations were surveyed using glue traps before testing began and once a month thereafter, just before the next round of pesticide treatment.
The laboratory showed that cockroaches are able to develop an “a resistance” to types of pesticide, meaning those which survived the spraying would go on to survive if a different class of pesticide was used.
They keep evolving extremely fast ….
Previously, it was believed that cockroaches only developed a resistance to one class of pesticide following exposure.
a female German cockroach can have 50 every three months, expanding out to 10 million descendants over four generations within 12 months – mean that chemical pesticides can swiftly become ineffective.
The pest controllers would have to use a mix of traps, improved sanitation in housing developments, and bug vacuums to reduce cockroach numbers.