Citrus Whitefly (Dialeurodes citri) is an exotic pest from India, likely introduced to FL in the mid-late 1800s. Until synthetic pesticides became widely used, citrus whitefly caused an estimated loss of 45-50% of citrus crops in Florida and the Gulf States. It is a common pest of gardenia in the landscape. It is very similar to other whiteflies in that it lives and feeds primarily on the undersides of leaves. Whiteflies suck out the plant juices causing yellowing of leaves. They also cause a sticky sap like substance, called honeydew, to coat leaves. This honeydew can attract other insects as well as allow black sooty mold to grow on coated surfaces.
Treatments can be applied whenever pest populations are noted on an individual tree. In addition, preventive applications with systemic treatments should be considered on high value host species that are growing in areas where heavy whitefly populations are present.
Other Treatment Practices
- Cultural treatments (e.g. root collar excavation, proper irrigation, soil management, etc.) need to be considered to improve/maintain plant health.
Signs of Damage
- Yellowing leaves and defoliation
- Sooty mold is sometimes associated with this insect
- Plant decline and dieback
- Adult is small orange and moth like but covered by a white waxy bloom
- Crawlers are tiny and pale green, have six legs, two antennae, and two red eyespots.
- The flattened nymph is pale green and scale-like.
- heavy infestations, eggs may be so numerous that leaves are malformed, and growth is impaired
- the honeydew excreted by the feeding whiteflies provides an excellent medium for the sooty mold fungus
Citrus whitefly adults
Nymphs on underside of gardenia leaf
Nympth under microscope
Trees At Risk
Wide range of hosts including, but not limited to:
- Females lay up to 125 eggs partially inserted in the lower leaf surface
- Eggs hatch in 6-21 days; crawlers emerge and begin to feed
- After the first molt, legs and antennae are lost
- After two additional molts pupae form
- There are 3 broods in AL and FL
- Adults emerge from T-shaped splits in pupal skins
- Summer broods take 2 months to develop
Always refer to product label for rates and approved uses. Some images courtesy of forestryimages.org or Wikimedia Commons. Use of the images does not imply endorsement of treatments.