Not sure what effect you used, but if you are able to assign a spot color to the effect, it can typically be output straight from illustrator.
I do this with outer glows for neon effects often, but you need to be able to assign a spot color.
It looks like you did a textured effect in the grass, so you could take that into photoshop and make a bitmap overlay and use the rest of the image from illustrator just with the texture overlay.