It can nearly ruin a good gardening day to walk outside and see one of your beloved shrubs or trees with chewed up leaves. Almost instinctively, an “all points bulletin” goes out to find the culprits.
But what clues might our plant be trying to tell us? A closer look and quite possibly there’s an existing problem that’s weakened our plant and left it vulnerable to infestation. Stressed plants emit chemical signals that attract insects. The insects are calling our attention to its distress.
Many things can stress a plant, such as drought, compacted soggy soil, and wrong amount of sunlight or the wrong soil pH for that plant. Also, excess nitrogen can be taken up and stored as amino acids, and certain insects can detect the presence of excess amino acids, encouraging them to feed on trees and shrubs that have been over fertilized.
Making sure each plant is in its ideal growing situation will go a long way in keeping plants healthy and stress free, and one of the best ways to prevent insect infestation.
Patty Frederick, former Smith County Master Gardener
Texas A&M AgriLife Extension Service