TAC: An Update

December 13, 2005 - 12:17

The Technical Advisory Committee, established to track Q biotype developments, shares the background on and suggestions for this new pest.

The Technical Advisory Committee (TAC) was established to respond to requests by the Q biotype Whitefly Taskforce for technical information. The following are the marching orders given to the TAC by the Whitefly Taskforce.

Technical experts with the disciplines and relevant expertise will work together to provide the technical information necessary to meet the goals and objectives of the taskforce. This technical committee will:

  • assess and validate information concerning the Q biotype of Bemisia tabaci in the United States and elsewhere;
  • develop and recommend the most technologically feasible means to prevent/limit the spread and mitigate the potential damage to U.S. agriculture that may result from the Q biotype; and
  • develop and recommend the most technologically feasible means to minimize economic losses to U.S. agriculture that could potentially result from the Q biotype.

Facilitated by a chair and a co-chair, the committee shall form subcommittees or working groups with the appropriate discipline and expertise to address specific scientific issues, including:

  • detection and survey,
  • diagnostics,
  • management,
  • communication, education and outreach, and
  • practical biology and ecology investigation.
  • The committee was asked to begin by developing surveillance and monitoring programs. Concurrent to this, the members began to outline how they would deal with management, education and other critical research needs. Therefore, the TAC committee defined four subgroups dedicated to the following issues:

    • survey and diagnosis,
    • management,
    • biology and ecology, and
    • education and outreach.

    Survey And Diagnosis

    With any new invasive species a number of issues must be addressed before management programs can be developed. The most important issue was to determine the regulatory status of the Q biotype. In order to manage a new, potentially devastating pest one needs to know how to identify it and then determine its distribution. During the early phases of the infestation it was still unclear whether this pest would be regulated or not. TAC reported that tools did not exist to allow for Q biotype identification without significantly impacting the movement of plant material. Other problems with regulation were discussed as well.

    USDA issued a State Plant Regulatory Organization (SPRO) letter dated May 31, 2005, addressing this issue. A SPRO letter is generally written for each “new” pest and is sent to all regulatory officials in each state and territory. The following is a quote from the letter: “Plant Protection and Quarantine (PPQ) is applying the current policy for the B biotype of the whitefly, Bemisia tabaci (‘non-reportable/non-actionable’), to the recently detected Q biotype. PPQ will facilitate the work of the ad hoc Q biotype Whitefly Taskforce, with the purpose of identifying the tools and principles necessary to minimize the impact of this high-consequence plant pest on effected industries.”

    The significance of this letter is that it removed any federal requirements to treat plants prior to movement. The federal government will not attempt to regulate the Q biotype. Given the fact that growers wouldn’t be able to tell the difference between the B and Q biotypes, they would have been forced into meeting zero tolerances irrespective of whitefly biotype — an impossible goal. TAC pointed out that regulation — or even the threat of regulation — could have resulted in such insecticidal pressure on all whitefly populations that it would select for resistant B biotypes and/or a super strain of the Q biotype.

    There are currently two methods used to identify biotypes. One method relies on DNA analysis and takes days to perform. Obviously this method would be totally unacceptable to the ornamental industry because growers would incur major losses from holding cuttings at ports of entry until the process was complete.

    The second method is much quicker and could be accomplished within hours using gel electrophoresis. However, this method would have also resulted in major delays, and the USDA-APHIS didn’t have the infrastructure to implement this kind of surveillance at their inspection facilities.

    Therefore, the Taskforce agreed that it would focus on state-conducted surveys and voluntary grower submission of samples. The TAC developed protocols for the submission of samples to the three laboratories listed on the Bemisia Web site (www.mrec.ifas.ufl.edu/lso/bemesia/bemesia/htm).

    A program was developed that allowed growers to submit anonymous samples for identification. In addition to these voluntary grower samples, 14 states were requested to develop a rigorous surveillance program of their own that would be supported by the various industries at risk from this new pest (see Q biotype surveillance on the Bemisia Web site). To date, our industry and the various state regulatory agencies must be commended for stepping up to the plate and doing what the TAC and USDA-APHIS requested. Many positive samples have been detected, but no regulatory action has been taken. The current situation, at press time, is that 15 states are considered positive for the Q biotype, with the whiteflies being collected from at least one, but not all, of the following plants in each state: gardenia, gerbera daisy, lamium, hibiscus, poinsettia or veronica.

    Management

    The TAC has defined the management of the Q biotype as all aspects of management: cultural, biological, chemical, physical, etc. Therefore, a broad outline covering all aspects was developed, and scientists willing to participate in research in those aspects are now a part of the TAC subcommittees.

    Another major step in this process was the willingness of the regulatory agencies to allow scientists to work with these insects outside of quarantine facilities once a state was determined Q biotype positive. This important development occurred only recently — after the TAC successfully argued the point. Prior to the TAC urging that this be allowed, only three laboratories in the United States were allowed to work with the Q biotype: one in Arizona and two in California. The California labs had to work in a high-level quarantine facility.

    Initially, Jim Bethke could not apply pesticides within the University of California, Riverside facility. However, he was given permission to conduct some pesticide efficacy trials under very strict conditions. These conditions made it extremely difficult for him to obtain information. Once the regulations were lifted for states considered infested, he was able to conduct many more trials that provided very useful information. (Read about his research on page 18.) Other researchers can now add to this work. I have recently been informed about some very interesting research being conducted at Cornell University by Dan Gilrein. His information should be available soon.

    Obviously, immediate control measures were of major interest by the Taskforce. The Taskforce held a meeting in Dallas, Texas, in early September to discuss all current laboratory, greenhouse and field efficacy trials on the Q biotype. Three subgroups were formed at that meeting to address the immediate needs of each industry individually. That way, each commodity would be provided with “best guess” management programs using current research.

    Biology And Ecology

    Research has shown that there are striking differences in the biologies and ecologies of the A and B biotypes. Therefore, the TAC recommends investigating the biology and ecology of the Q biotype as well. Some research is underway in Europe on these issues, but little if any has been conducted in the United States. These may not be immediate needs of the affected industries, but in the long run, will be important for management strategies. The TAC has outlined the biology and ecology research needs and is preparing documents that will guide interested researchers when the time comes.

    Education And Outreach

    The TAC considers this to be a very important issue. The sooner any information can be provided to the effected industries, the better. The sooner growers are aware of the problem and how to deal with it, the better.

    The ornamentals industry was “first out of the box” with an early, strong effort to inform growers of the best strategies known at the time. Lin Schmale’s article, see page 22, discusses the industry efforts — the trade press and major meeting sponsors have been extremely helpful in this regard. Articles have been published in all the major trade publications, a “Best Guess” document circulated and presentations were made at major industry meetings.

    In an effort to make information available in the most expedient way, a Web site was developed. As information becomes available it will be posted on the Bemisia Web site. This Web site has numerous documents developed by the TAC that present, in greater detail, the short- and long-range goals for the four TAC sub-groups, the reports from each of the TAC meetings and a link to an excellent reference list on the Q biotype whitefly.

About The Author

Lance Osborne is professor of entomology at University of Florida, Mid-Florida Research & Education Center, Apopka, Fla.; he is also a member of the TAC. He can be reached by E-mail at lso@mail.ifas.ufl.edu.

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