LTC 153-2011 Update: Gumbo Limbo MdAMIBEACH
OFFICE OF THE CITY MANAGER OF F I
NO. LTC #03 - LETT '16th 1MISSION
TO: a r a i era Bower and Me ers of the City Commission
FROM: Jorg M: Gonzalez, ity la.nager
DATE: June 17, 2011
SUBJECT: Update: Gumbo Limbo Spiraling Whitefly infestation
This Letter to Commission is.provided to give update on the recurring issues. relating to whitefly in
our City. As we advised you in LTC 289 -201 O, last October 28, 2010, a new tree pest, the Gumbo Limbo
Spiraling Whitefly, has infested trees, palms, and other plants throughout Miami. Beach and Miami -Dade
County. Infestations are typified by the production of a white waxy substance that discolors leaves and
drops onto surfaces near infested trees; sticky "honeydew; mold 'that black sooty mol that grows on the
honeydew. Although very messy, this whitefly, does not appear to kill the host plants, unlike. the Ficus
Whitefly which .arrived in South Florida a year or two , ago.
Now that warm weather has returned, whitefly numbers are again increasing and the City is receiving calls
from residents seeking information on the pest. In particular, they are inquiring on the effects of the Whitefly
on trees and palms, and what can be done to treat the infestation. A typical sequence with the arrival of new
insect pests is a population explosion due to unexploited resources and lack of predators and parasites,
followed by the eventual control of the pest as.the numbers.of predators and parasites increase and a
balance is attained. This is the anticipated scenario with the new whitefly. The following information is
provided. -in the event that inquiries come into your offices.
• The city chemically treats many trees on city property but does not have the ability to treat all of the
trees: On City property we have been using soil drenches with either Merit or Safari, which are systemic
pesticides recommended by the University of Florida. With soil drenches, the tree absorbs the pesticide
and distributes - it throughout the tree. When the whiteflies feed on the leaves, they ingest the pesticide
. die. Pest control is not immediate because it might take -a month or longer for the pesticide to
spread throughout the tree, but this type of treatment provides protection for a number of months.
• The alternative to a root drench is an aerial spray of pesticide which will kill every insect_it contacts, the
,good along with the bad. With this method, pest control is faster but short term, and whiteflies from
neighboring properties soon re- infest the tree. In most situations; the City does not use foliar sprays.
• The name.of this Whitefly species was recently changed from "gumbo limbo spiraling whitefly" to "rugose
spiraling whitefly. However, they are.one and the same.
• In an- effort to provide our residents additional information, the University of Florida fact sheet on the
whitefly..has been posted again on the City's web page. Information has also been included in the City's
MB magazine.
The Parks and Recreation .Department's Greenspace Management Division will continue to.monitor,this
infestation and adjust their control .strategies as new information � is collected. Additionally, they are
networking and sharing their experiences and treatment :programs with their colleagues in the. industry to
ensure we :are following a holistic approach that -is as effective, as possible. Please advise if you have
additional questions related to this information.
J'MG /HMF / KS /JO /CL H: \Parks \Greenspace \LTC_Gumbo Limbo Spiraling Whitefly_6 17 11.doc