Pest & Plant Management of South Florida - Pest Alerts

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09.15.08

THE FIG WHITEFLY INFESTATION
Singhiella simplex, or the fig whitefly, has been reported initially in Miami-Dade and is now in Broward and Palm Beach Counties. These pests attack ficus hedges and trees, most notably the weeping fig (ficus hedge), but has also been identified on other ficus species such as the banyan and Cuban laurel.

By sucking the juices out of the plant, the fig whitefly causes the leaf to wilt, yellow, stunt and drop. If left untreated, the host plant may eventually die. Due to the popularity and widespread use of ficus in landscaping in our area, the whitefly has a plentiful food supply.The fig whitefly appears to have come from Burma, China or India. Its presence in Miami-Dade County was confirmed in late 2007 and in Palm Beach County in July 2008. Its path to the north has been documented by the defoliation of the ficus hedges and banyan trees.

RECOGNIZING THE EARLY SIGNS
Identifying the problem starts with viewing the underside of the leaf. The adult whitefly is a white, gnat-like insect that will fly away when disturbed. The larvae, however are the real problem as they consume the leaf at this stage of their development. They appear as tan to light green ovals. After hatching, the whitefly leaves behind the empty skin, giving the leaf a dotted appearance with many small silver or white spots.

LIFE CYCYLE
The ficus whitefly's life cycle is approximately one month. The eggs are deposited on the underside of the leaf and hatch into crawlers, which subsequently begin to look for food. As they grow into adulthood, they generally are immobile and remain stationary as they feed. Detection at this early stage, known as the nymph stage, is very difficult. Defoliation occurs after several generations, according to Catharine Mannion from the University of Florida's Tropical Research and Education Center located in Homestead, Florida.

TREATMENT OF FIG WHITEFLY
How to treat fig whitefly is still in the developmental stage. The possible treatments include:

(1) doing nothing and hoping that the beneficials (natural enemies of the fig whitefly) would control the infestation,
(2) foliar sprays with contact and systemic pesticides and

(3) soil treatments.

Beneficials so far have not proven effective by themselves. Foliar sprays provide a quick knock down but only provide a short residual protection (up to six to eight weeks).

Foliar treatments, particularly with contact pesticides, are detrimental to beneficials. Soil treatments with liquid or granular systemic pesticides take longer to be absorbed and translocate (become effective) but have a longer residual protection. The brief history for fig whitefly has established the potential for foliar damage and possible death of the hedge. Does a preventative treatment make sense?

Treating the hedge before it becomes infested is less costly and avoids the difficulties of treating an infestation – extended period of defoliation or replacement. It is important to remember that the presence of fig whitefly in the early stages is difficult to establish. Identification once there is a major infestation and substantial damage is easy. The cost of closely monitoring your ficus hedges could be substantial and still miss the early stages of an infestation.

CONCLUSION
There is no definitive scientific study which demonstrates the most effective, cost-efficient form of treatment. At numerous seminars and meetings there have been reports of successful treatments both for established infestations and prevention. We feel that the short history of treating fig whitefly supports a preventative approach. In the future, greater experience, coupled with new treatments and pesticides, may modify our approach to treating the fig whitefly.

In the event you are experiencing an infestation and defoliation or wish to investigate a preventative treatment, please contact us at 561.547.4406. We would be happy to discuss the merits of various treatment options available to you and the related costs for each.

More information on the outbreak

PPMSF The University of Florida's Fig Whitefly Fact Sheet
PPMSF Florida Department of Agriculture & Consumer Services website


Articles:
PPMSF 07.24.08 – The Sun Sentinel
PPMSF 11.23.07 – The Naples News

Videos:
A video from local news channel, CBS4 discussing the outbreak

PPMSF
October 19, 2007
CBS 4 Miami