Elizabeth E. Grafton-Cardwell
UC Cooperative Extension IPM Specialist and Research Entomologist| UC Riverside;
Neil N. O’Connell
UCCE Farm Advisor | Tulare County;
Craig E. Kallsen
UCCE Farm Advisor | Kern County; and
Joseph G. Morse
Professor of Entomology and Entomologist| UC Riverside.
Photography by Jack Kelly Clark, Elizabeth E. Grafton-Cardwell,Craig E. Kallsen, and Alan A. Urena.
Scarring of the rind of citrus fruit can prompt packinghouse operators to downgrade the fruit from fancy to choice or even juice. If you as the grower can recognize the different types of scars you can differentiate between symptoms that indicate biological (e.g., insect, mite, disease, or snail), mechanical (e.g., equipment, hail, or wind rubbing), or chemical e.g., phytotoxic burn) damage. Once you know the causal agent you can take steps to reduce injury to future crops.
Orchards should be carefully monitored when fruit are small, the stage at which damage is most likely to occur. As soon as you observe signs of damage, make an immediate search for possible sources of the damage. It is much harder to determine the cause of fruit damage toward the end of the season because the insects or other causal agents are no longer present in the orchard and many types of injuries are by then similar in appearance.