Little crane grass's spirit was stronger than the average person's, and with his own training, his spirit wasn't weak. However, he couldn't release his spirit too far away. Most importantly, he couldn't use his spirit for too long even though he had a lot. If he kept it out for a long time, he could only sustain it for about two hours at most. After that, his spirit would be exhausted. If his spiritual power was really exhausted, it would affect his overall strength. In serious cases, he would even feel dizzy.
It was precisely because of this that little crane grass did not use its mental energy to explore the way at the start, but kept its eyes open as it advanced. However, the green mosquitos seemed to be very smart. They specifically attacked little crane grass's eyes. In order to not affect his speed, he had to cover his eyes as well and then speed up.