Navel Orange Leaf Curl: Aphids or Leaf Miners—Not Vegetable Oil

Leaf curl on citrus is caused by aphids (leave slimy residue, black sooty mold) or citrus leaf miners (squiggly trails inside leaves). Vegetable oil is not horticultural oil and won’t work. For aphids: blast with water, then insecticidal soap or Orthene. For leaf miners: horticultural oil (apply carefully) or ignore—they don’t affect fruit. Always follow label directions.