**Introduction**

DDT (dichloro-diphenyl-trichloroethane) was indeed a highly effective insecticide that gained popularity in the mid-20th century due to its effectiveness in combating insects, particularly mosquitoes. However, despite its initial success, DDT did not completely wipe out the mosquito population for several reasons.

**1. Development of Resistance**

**DDT: A Powerful Insecticide**

Initially, DDT was highly effective in killing mosquitoes and preventing the spread of diseases such as malaria. It was inexpensive, long-lasting, and had a broad spectrum of activity against various insect species.

**Resistance Mechanisms**

However, mosquitoes have the ability to develop resistance to insecticides over time. This resistance occurs due to genetic mutations that allow certain individuals in the mosquito population to survive exposure to DDT. These resistant mosquitoes then reproduce, passing on their resistance genes to the next generation.

**Selection Pressure**

The continuous use of DDT exerted a selective pressure on the mosquito population. As susceptible mosquitoes were killed off, resistant individuals survived and passed on their resistance genes, leading to the emergence of DDT-resistant mosquito populations.

**2. Environmental Persistence**

**DDT: A Persistent Chemical**

DDT is highly persistent in the environment, meaning it does not easily break down. This persistence allowed it to have long-lasting effects on insects, including mosquitoes. The extended presence of DDT in the environment ensured that resistant mosquitoes had a constant exposure to the insecticide, further favoring their survival and reproduction.

**3. Ecological Impact**

**Effects on Non-Target Species**

DDT had unintended consequences on non-target species, such as birds and fish. It caused thinning of bird eggshells, leading to population declines, and disrupted aquatic ecosystems. These environmental impacts raised concerns about the widespread use of DDT and led to its ban in many countries.

**4. Integrated Pest Management**

**A Holistic Approach**

Another reason DDT did not eradicate mosquito populations entirely is the recognition that a single chemical cannot solve the complex problem of mosquito-borne diseases. Integrated Pest Management (IPM) strategies were developed to address the issue comprehensively, combining various control methods such as biological controls, habitat modification, and targeted use of insecticides.

**Conclusion**

In conclusion, while DDT was highly effective as an insecticide, it did not wipe out mosquito populations due to the development of resistance, its persistence in the environment, ecological impacts on non-target species, and the need for a holistic approach to mosquito control. Understanding the limitations and drawbacks of relying solely on chemical control measures has led to the development of more sustainable and effective strategies to combat mosquito-borne diseases.

You cannot kill mosquito's whole population with ddt bcz they will grow resistance to it and this already happened. if u wipe out the whole mosquito population from Earth the ecosystem and food chain will get Disturbed and finally leading to the end of many species.