Question
have walnut trees with green like bunps on them what is this is it normal or is there a problem with tree? How can I fix problem or explain what is going on Thank you

Answer
These are insect galls formed by insects (more than likely small wasps or mites) that lay their eggs on the leaf secrete a chemical that causes the cells of the leaf to expand and form the gall over the egg. These are not harmful to the tree but if numerous could cause the leaves to drop early. There is no control since the life cycles of the insects are short and any treatment would need to be applied as the insects are laying their eggs--timing would be a problem and since the damage is slight no treatment is recommended.