The Fig Whitefly – A
New Pest in
Introduction: Recently, a
new pest was reported attacking ficus trees and hedges in
Description and Damage: The leaves of
ficus trees infested with whiteflies begin to turn yellow before the leaves are
dropped from the plant. Ficus trees
without their leaves are one of the most obvious symptoms of a whitefly
infestation. This whitefly has been most
commonly found infesting weeping fig (Ficus
benjamina) but has also been seen on F.
altissima, F. bengalensis (also
called “banyan tree”), F. microcarpa,
and F. maclellandii in
If the foliage is disturbed
the small, white gnat-like adult whiteflies can be seen flying from the
foliage. The adult whitefly resembles a
very small moth with a yellow body and white wings with a faint grey band in
the middle of the wings. Immature stages (eggs and nymphs) can be found
primarily on the underside of the leaves. Prior to adult emergence, the nymphs are
tan to light green discs with red eyes. The
underside of infested leaves look like they are dotted with small, silver or
white spots which are actually the empty “skin” of the pupae after the adult
emerges.
Red
eyed stage Leaf
infested with whitefly Immature
whiteflies Adult
whitefly
Biology: The biology of the fig whitefly is not known,
however, it is probably similar to related species in
Management: Although efforts to understand and control
this pest are ongoing, there are several potential options for whitefly
control. However, it is necessary to
consider the site (landscape, hedge, large tree, container, production, etc),
the size and number of trees, and the surrounding environment before taking
steps to control this pest. For large trees, for example, a foliar spray may
not be possible.
In the landscape, several natural enemies have been observed attacking
this whitefly which can play an important role in controlling this pest. Efforts to introduce other natural enemies
are being considered. Awareness of these
natural enemies is very important so decisions for additional control measures
can be made wisely so as not to also kill the natural enemies.
Beetle
predator Beetle
predator Parasitized
whitefly Parasitic
wasp
Monitor your ficus plants for early signs of an infestation
because it will be easier to manage the pest before it builds to high
populations and causes major damage.
Also, if infested trees or hedges are trimmed, either leave the
clippings on the property or if removing, bag the clippings to reduce the
chance of spreading the insects. If
clippings are being transported in a truck, be sure to either bag them or cover
these clippings with a tarp.
Insecticidal soap or oil sprays may be an
effective method of control for homeowners,
but, thorough coverage of the undersides of the leaves is especially
important. It will also be necessary to
repeat these applications every 7 to 10 days.
The use of other insecticides may be necessary to control this
pest. However, it is important to use
products that will not be detrimental to the natural enemies. These products would include Bayer Advanced
Tree & Shrub Insect Control (imidacloprid) and Spectricide Tree and Shrub
Insect Control (dinotefuran) applied to the soil. Protecting natural enemies
may be a critical component in the long-term
control of this pest. Other products
available for homeowner use include Ortho Bug-B-Gon (bifenthrin), Bayer
Advanced Rose and Flower Insect Killer (cyfluthrin), Sevin (carbaryl),
Malathion, and others, however, these products may also be harmful to the
natural enemies. All of the above
products can be found at garden centers and hardware stores.
There are also numerous insecticide options
available for professional use in the
landscape and for growers which can be found at agricultural and
landscape chemical suppliers.
Insecticides with systemic properties may be very useful in whitefly
control because they can be applied as a drench to the soil and many times
provide longer lasting control. These
insecticides include the neonicotinoids [Celero (clothianadin), Flagship/Meridian
(thiamethoxam), Marathon/Merit (imidacloprid), and dinotefuran (Safari)]. These products also tend to be less
disruptive to the natural enemies. After
drenching, apply foliar sprays as needed if whiteflies are present. In addition to the neonicotinoid insecticides
listed above, insecticides that can be applied to the foliage for whitefly
control include Aria (flonicamid), Avid (Abamectin), Azadirachtin, Distance
(pyriproxyfen), Endeavor (pymentrozine), Endosulfan, Judo (spiromesifen), Talus
(buprofenzin), and Tristar (acetamiprid).
Rotation of insecticides among different modes of action is critical in
the management of pests and is especially important for whiteflies that have
been shown to develop resistance to insecticides. If plants have received a neonicotinoid
drench, DO NOT spray with another insecticide in this group. Also available are products that contain more
than one insecticide such as Allectus (imidacloprid + bifenthrin) which is for
use in the landscape and Discus (imidacloprid + cyfluthrin) which is for use in
production. Sometimes these products are
useful because you get the benefits of two different insecticides, however, it
is still important to consider how these products will affect the natural
enemies. No matter what insecticide is
selected, it is very important to check the insecticide label to determine if
the insecticide can be used in the landscape, in production, or either. Note that many of the products containing a
systemic insecticide also have restrictions about using near water (ponds,
lakes, rivers, etc.). Always follow the
label directions – “The label is the law”.
Although your ficus tree or hedge may appear
to be dying after losing most of it leaves, it may still be alive. If the twigs are still supple, the plant will
produce new leaves in a few weeks. As
soon as new growth is evident, a systemic insecticide applied to the soil may
provide protection to the new growth.
For more information, contact your local Extension
agent for additional information. Please
visit the UF/IFAS Miami-Dade County Extension website for updates http://miami-dade.ifas.ufl.edu or http://mannion.ifas.ufl.edu
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The use of trade names in this publication is solely for the purpose of providing specific information. UF/IFAS does not guarantee or warranty the products named, and references to them in this publication does not signify our approval to the exclusion of other products of suitable composition. All chemicals should be used in accordance with directions on the manufacturer's label. Check the label carefully as this information does change and our publications may not have the latest information. Use pesticides safely. Read and follow directions on the manufacturer's label.