Which of the following can be a consequence of ineffective fly management?

Ineffective fly management can lead to the spread of diseases, making this the correct choice. Flies are known vectors for numerous pathogens, including bacteria and viruses, which can be transmitted to humans, livestock, and wildlife. When their populations are not properly controlled, the likelihood of disease outbreaks increases, resulting in health risks for both people and animals.

On the other hand, increased populations of beneficial insects or a reduction in overall pest pressure might not be direct outcomes of poor fly management. Rather, these scenarios generally occur under active and effective pest control measures. Additionally, enhanced quality of life is tied to successful management practices; ineffective management would most likely lead to issues such as health problems due to increased fly populations, negatively impacting quality of life.