Q. Something is eating the leaves of my small grapefruit tree. I have checked it often to see if I could see the pest that was the culprit, even at night, and cannot find anything. What do you recommend?
A. Without seeing it I am not sure anything is eating your grapefruit leaves. Wind damage to the leaves is the most common reason for damage to citrus leaves that resembles feeding damage by insects. We did have some pretty good winds recently. Wind damage most resembles tearing, shredding or ripping of leaves. I would not apply an insecticide if you are not convinced it is insect damage and then only if the damage is not recoverable by the tree without your assistance or interferes with fruit production.
Wind damage to persimmon leaves.