Common Orchids Pests : Sap Feeding Insects : Scale

Scale on Orchids

Symptoms:

Scale are sucking insects that attach to and feed on the underside of leaves, in leaf axils, on pseudobulbs and on rhizomes. They often are hidden under old leaves and pseudobulb sheaths. Severe infestations cause chlorotic areas to appear on the leaves and plant surfaces which will yellow and may darken and can cause the leaf to drop prematurely.

Treatment:

If there are only a few scale, use a Q tip dipped in isopropyl alcohol or toothbrush dipped in a pesticide like Malathion, Orthene or Safer Soap (used per label instructions) to physically remove scale. For more severe infestations, apply the pesticide at the crawler stage and repeat the application 2 weeks later. Be sure to spray all plant surfaces, particularly the undersides of leaves and leaf axils. 

Prevention: 
Remove old leaf and flower sheaths to eliminate scale hiding places and allow easy inspection. Check new plants carefully before adding to the growing area.