Biological Control Of Weeds: Why Does Quarantine Testing Take So Long?

Bio Control Labby Gary R. Buckingham and Christine A. Bennet - USDA/ARS and the University of Florida/IFAS - USDA/ARS
Presented at the Florida Exotic Pest Plant Council Annual Meeting, 2002.

QUARANTINE research is often slower than other types of research, which can be frustrating for those funding the research or waiting for field releases of the agents. Although many of the problems encountered during testing are the same as those encountered elsewhere, they are often more prevalent in quarantine. Space and manpower is severely limited in most quarantine facilities, including the Florida quarantine facility at the Florida Division of Plant Industry, Gainesville. New planned quarantines in Ft. Lauderdale and Ft. Pierce should operate more efficiently initially, but in time, their projects will increase and they will have similar problems. In this poster, we present some of the items that contribute to the slow progress of quarantine programs.

UNDESCRIBED SPECIES or named species with unknown host plants and unknown biologies are common among potential biocontrol agents. Some are studied at our foreign laboratories before being sent to quarantine, others are sent directly to quarantine. Examples of questions needing answers before rearing, testing, and eventually establishing field populations of new species are:

  • Will they mate immediately, are special conditions needed?
  • Will females oviposit right away, is there a preoviposition period?
  • Is there a diapause (winter or summer rest period), can it be prevented?
  • What temperatures are best, which are lethal?
  • Are eggs and wing muscles mutually exclusive?

TEST PLANTS, both cultivated and native, must be obtained at the beginning of each project and maintained or replaced as the project continues. Many native plants have no readily available horticultural data. Pest problems are especially troublesome because we are cautious with the use of pesticides – mostly we spray soap alone or with corn oil. Control of mealybugs, aphids, thrips, and caterpillars is often by the thumb-forefinger technique.

The melaleuca snout beetle was tested with over 100 plant species, although many were by cuttings from cultivated trees. We currently have 34 species of ferns in our screenhouse for the Old World climbing fern project. Outside the screenhouse, we hold melaleuca and other myrtaceous species which need to be covered with plastic during winter.

Host plant cuttings are field collected to provide the amounts needed to rear vigorous colonies of foliage-feeding biocontrol agents. Weekly shipments of melaleuca were sent from Ft. Lauderdale during the melaleuca snout beetle testing. Luke Kasarjian now sends weekly climbing fern shipments.

REARING AND TESTING of the potential biocontrol agents requires a large and steady supply of insects. As mentioned, large amounts of foliage are field collected for leaf feeders. Seedlings and saplings must be grown as potted plants. Cages must be made or adapted for the agent. Simplicity has been our motto because of costs and lack of storage space for large, solid cages like those made of Plexiglas or wood. The diversity of agents, i.e.., weevils, sawflies, bugs, psyllids, flies, requires diversity of cages and methods. Weevils require adult and larval feeding tests in addition to oviposition and larval development tests. Flies only require oviposition and larval development tests. Melaleuca psyllid DNA was checked for micro-organism DNA, which was then compared with a plant pathogen database. Plants were also held for up to a year after psyllid feeding to see if disease symptoms would develop.

DISEASE CONTROL is imperative for rearing programs. The white fungus, Beauveria bassiana, was omnipresent during our aquatic weed projects and was kept at low levels by constant bleaching of containers and dipping of insects in a non-insecticidal fungicide. For the first time, we recently have had a protozoan pathogen invade our colonies. The climbing fern moths, "Cataclysta" and Neomusotima, have been infected, apparently through the field collected fern. Eggs from individual females are kept only if dissections suggest that the female was non-infected. Samples of her larvae are dissected as they mature. If no pathogens are found the larvae are allowed to mature and samples of adults are dissected. If they are clean, their progeny are used to start a new colony. We are currently finishing this protocol for both fern moths. We are also bleaching the fern before feeding the larvae. It takes about 3 months to clean a colony and to begin testing again.

PERMISSION TO RELEASE the biological control agents must be obtained from the USDA, Animal and Plant Health Inspection Service (APHIS) and from the Florida Department of Agriculture and Consumer Services, Division of Plant Industry (DPI). Both agencies have advisory committees that include representatives from other agencies. If the federal Technical Advisory Group (TAG) for the biological control of weeds recommends release after reviewing a proposal submitted by the petitioner(s), then APHIS, with the cooperation of the petitioner, prepares an Environmental Assessment. After the US Fish and Wildlife Service has been consulted, notice of the EA is published in the Federal Register. If, after considering the responses to the notice, a finding of no significant impact (FONSI) is made by APHIS, the petitioner submits an application for a release permit. This application must be approved by DPI before APHIS sends the petitioner a release permit and shipping labels.

Preparation of the proposal for release can take 3 months to a year, depending upon the need for additional testing, the amount of data to be summarized, the number of other projects, and various other factors. The TAG response can take 3 to 5 months. The Environmental and Biological Assessment preparation and consulting has been taking 1 to 3 years or more. The federal register announcement and FONSI take no more than 1 to 2 months. If a copy of the release proposal is submitted to DPI after the TAG response and has been approved by the Florida Arthropod and Pathogen Introduction Committee, the DPI approval and APHIS permit issuance takes only days.