What Loretta's Katydid Did — Lois June Wickstrom

The tree Grandma brings has aphids. Grandma says Loretta must kill the aphids before they kill the tree, but Loretta refuses because she loves insects. One day, a katydid finds the tree. It eats all the aphids. Then the katydid starts eating the tree. Loretta doesn't want to get rid of the katydid. How will she keep her orange tree healthy for the science fair? With a little secret help from the insect world, Loretta just might win first place.