Bronzing of apple tree leaves is caused by the:

• A. Codling Moth
• B. European Red Mite
• C. San Jose Scale
• D. Plum Curculio

Answer: (B)

Bronzing of apple leaves comes from the feeding injury of tiny mites that suck sap from the leaf tissue. The European red mite specifically feeds on the underside of leaves, causing the upper surface to take on a bronze or stippled appearance. This bronze coloration is a distinct symptom of mite feeding and can be accompanied by leaf curling or premature drop when populations are high.

This symptom is not typical of the other pests listed. Codling moth damages fruit by boring into the fruit itself, not by bronzing the leaves. San Jose scale involves scale insects that attach to bark, twigs, and sometimes fruit, causing small, rounded scales rather than bronzing on foliage. Plum curculio creates surface scars and dimples on fruit and can cause fruit drop, not the bronze leaf effect.

Because bronzing is characteristic of mite feeding on leaves, European red mite is the best answer. To manage, monitor populations and use appropriate mite-control methods, such as horticultural oil sprays or miticides, while maintaining tree vigor.