Whitefly

• Healthy leaves are green and glossy.ficus benjamina image by Unclesam from Fotolia.com
  
  If the leaves on a ficus hedge are turning yellow and leaves are dropping off, a whitefly infestation is probably to blame. Check the undersides of the ficus leaves where silvery-white small dots may be spied. These are the dead bodies of the juvenile bugs. Mature whiteflies look like little white moths. If the hedges are devoid of leaves but the twigs are supple and will still bend, the plant is alive and may show new growth. The hedge should be treated as soon as the leaves appear. Leave fallen leaves on the ground as a mulch.
  
  

Treatment

• According to the University of Florida IFAS Miami-Dade County Extension, whitefly-affected hedges should be sprayed with imidacloprid, which is a chemical control for insects that attack trees and shrubs. They also recommend applying dinotefuran, which is another insect controllant, to the soil. The treatments do not need to be re-applied for at least six months.
  
  

Thrips

• Ficus hedges can also be subjected to thrips. These little yellow or dark brown bugs are hairy and have pointed rear ends. The young bugs are wingless. When thrips attack a ficus hedge, leaves start curling and silvery gray wounds on the leaves may be noticed. These are the sites where thrips have been feeding. An insecticidal soap sprayed on the thrips should help control the problem.
  
  

Scale and Mealybugs

• Scale and mealybugs also attack ficus hedges. Both types of pests are virtually undetectable until ample damage has been caused to the plant. Check the ficus for a cotton-like substance on the undersides of leaves. A black mold may also be present. These are indications that mealybugs are present. Spray insecticidal soap on affected plants.
  
  

Aphids

• Aphids can suck a plant dry.reed aphids image by Adrian Hillman from Fotolia.com
  
  Aphids can be brown or green and will suck the sap from healthy ficus twigs and leaves. They release a honeydew that attracts ants so spying ants beside a ficus hedge is a good indication that aphids have attacked the plants. Strong jets of water from a garden hose will dislodge the bugs and/or spraying with insecticidal soap will dessicate the fragile bodies.