Plum Tree with Sticky Fruit: Scale or Borer Infestation

10-year-old plum tree loaded with tiny plums covered in clear sticky substance (dried like candy syrup). Fruit falls if touched. Owner in St. Martins, NB, Canada.

Two Likely Insect Causes

1. Scale insects: Small, oval, immobile bumps on branches (brown/black). Scrape with fingernail to confirm. They excrete honeydew (the sticky stuff).
2. Fruit borer/worm: Cut open fruit; look for larvae or tunneling inside.

Treatment

• If scale or borers found: Fruit tree spray from garden center (follow label for edible fruit).
• May still salvage some fruit this year.
• Next year: Start spraying at bloom; repeat every 2–3 weeks through season.

Regular spray schedule is essential for clean fruit.