Page 143 - Florida Pest Control Examinations

ASH WHITEFLY ADULTS & EGGS

Photo Courtesy of UNIVAR Photo Courtesy of UNIVAR
ASH WHITEFLY INFESTATION
ON RAYWOOD ASH

Photo Courtesy of UNIVAR Photo Courtesy of UNIVAR
1.Antenna-elongated, threadlike 6.Thorax-wings attached WHITEFLY
2.Eyes- 2 7.Petiole- none
3.Head- attached to thorax with stylet 8.Abdomen- round 1 2 5
4.Legs- 6 9.Color- white
5.Wings- 2 pair 10.Other- many sizes in this family
Life Cycle
The cycle begins when the female adult Whitefly walks across the leaves and
deposits characteristic waxy spirals on the underside. She then lays eggs
among them. The eggs hatch into a nymph called a “crawler”, which then
develops through three instars before reaching the adult stage. The nymphs 6
create the familiar waxy filaments that coat the underside of leaves. Wind
can move the new adults from plant to plant, but they prefer to stay grouped
together inhabiting the lower surface of a particular leaf their entire life. Photo Courtesy of UNIVAR

WHITEFLY Actual size 1/8”

Both immature whiteflies and adults feed by siphoning the juices out of leaves. Over time, this can se-
verely damage the plant. Common signs are leaf curl, yellowing, and early leaf drop.

Another byproduct of this feeding is a sticky substance called “honeydew,” which in turn creates a black
fungus called sooty mold. Sooty mold fungus is not only unattractive, but will impede photosynthesis,
which every plant needs.

Many different species of whitefly exist, but their life-cycles are very similar. The largest problems come
from the Sweet Potato Whitefly, which attacks spring vegetables, and the Silverleaf Whitefly. Both have
unusual coloring as their bodies are yellow. They can also infest ornamentals as well as cotton crops.

A recent variety to arrive in Florida was the Ash Whitefly, which came from Mediterranean areas in
1988. It infests many fruit trees—especially citrus, has spread rapidly, and resists efforts at control and
eradication.

The Greenhouse Whitefly also infests citrus and many potted plants, and as the name suggests is found
mainly in greenhouses. It leaves a fine filament of white strands on the underside of leaves instead of a
waxy substance. The Citrus Whitefly and Banded-winged Whitefly are also problems.

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