Lawns love compost. Lawns love rock dust. Blend the two together for best results. Follow maintenance program I have outlined for you. In this environment, the lawn and its bio- system will be operating under stress.
Stress is the most important factor in pest control.
The Humus levels have dropped below optimum. Water effects stress. High nitrogen fertilizers kill the soil and cause a great deal of stress. Avoid using Urea at all costs. More than any other element of climate, temperature will determine which type of lawn will grow where.