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Whitefly fungi

  Q:  What is wrong with my citrus tree?  I see little white flies whenever I get near the fruit or leaves.  I turned some of the leaves over and saw these orange specks.  Is this an insect or a disease?

A:   Actually the orange spots you see are neither an insect nor a diseaseBeneficial fungus on citrus. The spots are beneficial fungi which attack the young stationary stage (pupae) of a common citrus pest called the white fly. The white fly is an important pest of many fruits and vegetables as well as ornamental plants. In large commercial plantings of citrus, citrus whitefly and cloudywinged whitefly are largely controlled in rainy weather by whitefly fungi. Some important species are the red fungus (Aschersonia aleyrodis Webber) and the brown fungus (Aegerita webberi Fawcett).  A yellow fungus, Aschersonia goldiana, does not attack the citrus whitefly, but is very effective against the cloudywinged whitefly. The presence of the yellow fungus guarantees that cloudywinged whitefly is present. These fungi are generally present in all citrus groves in Florida and increase in numbers when the proper environmental conditions prevail. These fungi are commonly referred to as “friendly fungi,” and the two major species are often referred to as red Aschersonia and yellow Aschersonia.  This is another example of leaving things alone and letting nature take its normal course of action.  We would not recommend any chemical application as the fungi are probably managing the white fly population quite well.  This information was taken from a publication titled, “Your Dooryard Citrus Guide: Common Pests, Diseases and Disorders of Citrus” by James J. Ferguson from the UF/IFAS http://edis.ifas.ufl.edu/pdffiles/HS/HS12200.pdf