How to avoid bright pixels in grass

In case the bright spots are caused by sun being reflected by the grass blades, this is a physically correct phenomenon that you can also observe in real life (examples: waves on the water reflecting sun, “sparkling” snow).

Example of bright pixels visible in grass:
glossiness = 1.0

To decrease this effect, you can:

1. Lower glossiness value of the grass material:

Glossiness lowered from 1.0 to 0.5:

After lowering material’s glossiness to 0.5, sun reflections became “softer” and more realistic:

2. Disable reflection visibility for Corona Sun:

Result of disabling sun’s reflection visibility:

There are no bright pixels but the grass looks less realistic. Using this option will globally disable sun reflections for all objects.

Source: Corona Renderer Forum