Which pest on fruit trees is best managed by applying oil and is usually found beneath loose bark?

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

Answer: (B)

Horticultural oil is especially effective against scale insects because the oil smothers the insects and blocks their breathing when they are exposed on the tree, including stages that hide under bark crevices. San Jose Scale is a scale insect that commonly overwinters under loose bark on fruit trees, so an oil spray reaches and suffocates them while they’re protected there. This makes oil applications the best approach for this pest, particularly during the dormant or pre‑bud stage when they’re most exposed to the spray. Other pests listed don’t fit this scenario as neatly: codling moths are caterpillars inside fruit and managed more by traps or targeted insecticides, European red mites and plum curculio aren’t characteristically found under loose bark in a way that oil alone addresses best, and their control relies on different strategies.