International Produce Training

Apples- Insect Damage

Insect damage, affecting apples is pretty much straight forward.  There are specific scoring guidelines for “injury,” “damage,” and for “serious damage.”  All worm holes are scored as a free from defect, always score as a serious damage defect when found.  If insect stings are found, the following guideline is offered:

  • 51.316 Injury. (h) Insects: (1) Any healed sting or healed stings which affect a total area of more than one-eighth inch in diameter including any encircling discolored rings.
  • 51.317 Damage. (j) Insects: (1) Any healed sting or healed stings which affect a total area of more than three-sixteenths inch in diameter including any encircling discolored rings.
  • 51.318 Serious damage. (h) Insects: (1) Healed stings which affect a total area of more than one-fourth inch in diameter including any encircling discolored rings.

This defect was found on Pink Lady apples.

 The defect is showing raised areas, hard, and the underlying flesh is not affected.  What is it?  This is a type of insect injury, caused by the Plum Curculio insect.  From NC State’s website; “A female Plum Curculio uses her snout to cut a crescent-shaped slit beneath each egg she lays in order to keep the growing apple from crushing the egg. This slit becomes a crescent-shaped scar as the apple grows, though the damage is often only cosmetic. However, larvae sometimes bore tunnels, and heavily-infested fruit may become knotty or fall to the ground. Later in the season, adult beetles may create numerous round punctures in fruit skin.”

So if the defect is identified as being caused by the insect, then the above mentioned scoring guideline is followed……right?  No, the scoring guideline for the defect caused by the Plum Curculio insect is unique.

The USDA’s scoring guideline is as follows; “Punctures made by the Plum Curculio for the purpose of laying eggs usually result in crescent-shaped, corky, russet scars, which shall be scored on the basis of russeting rather than insects.”  This defect resembles the defect, russeting.  If the defect is smooth, slightly rough or rough score according to the specific guideline for each.  The following are definitions for damage by russeting:

  • Smooth solid russeting, when an aggregate area of more than 5 percent of the surface is covered, and the pattern and color of the russeting shows no very pronounced contrast with the background color of the apple, or lesser amounts of more conspicuous solid russeting when the appearance is affected to a greater extent than the above amount permitted.
  • Slightly rough russeting which covers an aggregate area of more than one-half inch in diameter.
  • Rough russeting which covers an aggregate area of more than one-fourth inch in diameter.

The apple in the top image would be scored as a defect.  The second image is zoomed in, making it difficult to determine the defect’s size as in comparison to the size of the apple.

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