Which cultural control practice involves maintaining the height of turfgrass at three inches?

Maintaining the height of turfgrass at three inches is associated with frequent mowing because this practice helps promote a healthy and resilient lawn. Keeping the grass at the correct height is essential for the overall health of the turf. When turfgrass is mowed at an appropriate height, it encourages stronger root development, allows for better air circulation and light penetration, and enhances the grass's ability to withstand pests and diseases.

In contrast, the other options do not directly relate to managing grass height. Heavy fertilization can lead to excessive growth, which may necessitate more frequent mowing but does not itself maintain a specific height. Watering less frequently can stress the grass and potentially affect its growth and height negatively. Regularly applying pesticides does not address the height maintenance of the grass at all, as its focus is on controlling pests rather than cultural practices to promote healthy growth. Frequent mowing at the correct height is essential in maintaining an optimal growing environment for cool-season turfgrass.