Did you know rind scarring damage caused by the same pest could look different in mandarins and sweet oranges?

A NEW extension article "UCANR publication 8708", brings you a pictorial guide to help differentiate between the damages caused by the same pest on mandarin species and sweet oranges.

Early-season insect pests, such as katydids, earwigs, and citrus thrips feeding on newly developing fruit can cause rind scarring damage. Resulting scar damages can lead to the downgrading of fruit in packinghouses causing huge economic losses for growers. Highly valued for the fresh citrus fruit (unblemished), managing these surface-feeding pests and minimizing their damage is vital to California citrus growers. Several resources, such as “Photographic Guide to Citrus Fruit Scarring” UCANR publication 8090, published in 2003 exist to help identify various types of damages. But previous work was mainly based on work with sweet oranges.

With the increasing acreage of mandarins in California, the need for identifying early season rind scarring damage caused by several pests was recognized. Dr. Bodil Cass led a group of researchers from UC Davis in evaluating grower data and conducting experiments at the Lindcove Research and Extension Center. The results of this research are now published as a photographic guide that provides information on how three early-season pests cause damage to mandarin species compared to sweet orange.

What are the main findings?

• Damages caused by early-season pests are different in tango mandarin and clementine mandarin.
• Katydids do not cause feeding damage on tango or Afourer mandarins.
• Katydid damage on clementine looks like worm damage on sweet orange. It can cause maturing fruit to split and then drop.
  
  Figure. 1. Pictorial summary showing the different types of damages caused by katydid feeding on young and mature fruit.