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How to Get Rid of the Scale Bug in Fruit Trees

By Jay Golberg ; Updated September 21, 2017

Scale insects start out as tiny nymphs that insert a thread-like sucking mouth part through the bark of a fruit tree weakening the tree over time. As they mature, they secrete a scale-like covering that increases in size. A mature scale insect covering is round with a raised nipple-like structure and is the same color as the bark of the tree it infects, making it difficult to see. Because the insect lives inside the waxy scale-like coating, control with a contact insecticide is difficult. If not controlled during the dormant season, scale can spread to developing fruit in the spring. The best control method is spraying with dormant or horticultural oil in early spring, which smothers and kills the scale.

How to Get Rid of the Scale Bug in Fruit Trees

Prepare to spray trees on a calm, early spring day when they are close to bud break. This means the green buds are about to sprout or flower but are not showing any flower petals, leaves or color. The ideal outdoor conditions are when temperatures will stay above freezing and there will be no rain for 24 hours.

Mix dormant oil spray according to directions while wearing protective glasses and rubber gloves. Pour in garden sprayer.

Spray fruit trees by completely covering all limbs and trunk of tree. Shake or agitate sprayer often to prevent clogging and to keep oil solution mixed well. It is OK to use a heavy application because complete coverage is important for control.

 

Things You Will Need

  • Dormant oil
  • Garden sprayer
  • Fruit tree
  • Rubber gloves
  • Safety glasses

Tips

  • Mixing an insecticide such as malathion with dormant oil gives better control of scale insects.
  • Application of dormant oil must be made for at least three consecutive seasons for control.
  • Other names for dormant oil are scale emulsion, superior oil or horticultural oil.
  • Prune trees as required before applying dormant oil. There is no point spraying vegetation you will be pruning.

Warnings

  • Dormant oil is toxic to any nearby green plants it might contact, so use with care.
  • Follow all instructions on toxic chemicals carefully.
  • Motor oil of any grade is not an appropriate substitute for dormant oil.
  • Never use an oil or insecticide containing sulfur on fruit trees as it could do long-term damage.

About the Author

 

Jay Golberg is a certified Texas nursery professional and professional project manager. He has 30 years of business and farming experience and holds bachelor's degrees in English writing from St. Edward's University and finance from Lamar University.