It is possible that a plastic film that kills harmful soil insects could also damage the micro-ecology of the soil. Micro-ecology refers to the interactions and relationships between microorganisms, such as bacteria, fungi, and protozoa, that live in the soil. These microorganisms play important roles in the decomposition of organic matter, nutrient cycling, and the suppression of plant diseases.

If a plastic film is used to kill harmful soil insects, it is likely that it will also kill or inhibit the growth of beneficial microorganisms. This could disrupt the balance of the micro-ecology and lead to a number of negative consequences, including:

- Reduced decomposition of organic matter, leading to a build-up of dead plant material and a decline in soil fertility

- Reduced nutrient cycling, making it more difficult for plants to access the nutrients they need

- Increased susceptibility of plants to diseases, as the beneficial microorganisms that normally suppress these diseases are reduced in number or eliminated

In addition, the plastic film itself could also have a negative impact on the micro-ecology of the soil. For example, the plastic could block sunlight from reaching the soil, which could inhibit the growth of photosynthetic microorganisms. The plastic could also release harmful chemicals into the soil, which could further damage the micro-ecology.

Overall, it is important to consider the potential negative effects of using plastic films to kill harmful soil insects before using them. It may be necessary to use alternative methods of pest control that are less harmful to the micro-ecology of the soil.