This month, we talk about an exciting program we’re working on with the Division of Plant Industry for non-chemical ways of controlling Asian citrus psyllid. We’d also like to introduce a new “right here, right now” technology solution we developed to help with our role in the program. Psyllids are small insects that transmit a disease called citrus greening, which many consider the most serious production issue in Florida. There are a lot of options for controlling psyllids, including chemical treatments and strategic options like Citrus Health Management Areas. Psyllid interventions are increasingly complicated, and involve an intricate series of field surveys, calculations, regulatory management and treatment maneuvers to achieve control. Chemicals can be effective, but require repeated applications so that the insect is continuously suppressed. This practice isn’t sustainable. Citrus Health Management Areas are also effective, but not everyone can fully participate. For example, growers with commercial blocks interspersed between housing subdivisions and abandoned groves (often owned by absentees) can’t aerial spray or easily remove declining trees. We need new ways to simplify management practices and control psyllids with fewer chemicals. In our case, non-chemical controls won’t replace established practices, but they can extend the range of psyllid control outside the reach of other methods. The Tamarixia Release Program by the Florida Department of Agriculture and Consumer Services is one of several programs working toward these goals. This article reflects our experience in the program and shows how you can participate and release Tamarixia wasps in your groves, too.
Tamarixia radiata: a beneficial wasp that attacks psyllids While there are other beneficial insects that attack psyllids in Florida (lady beetles are especially good at it), Tamarixia radiata is one of two parasitic wasps released by the state that provide additional control. Figure 1 shows a T. radiata wasp (upper right) and a parasitized citrus psyllid (lower left). The wasp is established in Florida and is providing varying levels of control. There’s good reason to expect it’ll do well here since it has also shown excellent control of psyllids on Reunion and Guadeloupe Islands. One way to improve its performance is by releasing even more wasps in locations where they have a good chance to thrive. An excellent article on the background, rearing and release of the wasps in Florida will be published soon in Citrus Industry magazine if you’re interested in that program.
Tamarixia Release Program The Tamarixia Release Program is managed by the Bureau of Methods Development and Biological Control at the Division of Plant Industry, Florida Department of Agriculture and Consumer Services. They have two facilities–in Gainesville and Dundee–which combined rear over a million wasps per year. Within a year, they’re expected to scale production up to about 400,000 per month. We recently started working with Dr. Robin Stuart at the Dundee Biological Control Laboratory (Figure 2) to release wasps and reach trees and plantings near ours that we’re unable to treat for psyllids in other ways. (Our targets are wild, abandoned and backyard trees in an urban-agricultural interface.) The lab provides wasps in tubes containing 200 individuals, which we set in and around our targets. We came up with a 1-inch PVC pipe staked under the tree and extending up into the foliage as an efficient way to deploy the tubes. Once a week, we switch out the prior week’s tubes for new ones containing a fresh group (Figure 3), which allows us to service 35 tube locations in under 2 hours. Our PVC holding tubes can easily be moved to target emerging flush. So far, we’ve released over 65,000 wasps in our area. We’ll begin surveys for parasitized psyllids when they populate more susceptible flush in our target trees.
Importance of data quality In return for participation, the state asks that we provide records of our releases. This data is for mapping and it’s vital to the program because it’s used to evaluate survivability and effectiveness of the wasps. Drs. Robin Stuart and Eric Rohrig developed a form to complete for each release that documents location, weather, tree and psyllid conditions. We also note the number and percentage viability of the released wasps. One consideration as we were gearing up the program was that we would accumulate a lot of forms over many releases. We didn’t want to manage too many computer files and forms, so our solution was to create a custom app to consolidate the forms into one computer file for tracking and reporting vital data after each release. Our app is called, the “Tamarixia Tracker”. You can learn more about the app on our Tamarixia Tracker website.
Tamarixia Tracker App for Desktop, iPhone and iPad To design our app, we started with the form provided by Drs. Stuart and Rohrig, then converted it into a WYSIWYG single-parameter relational database (Figure 4). This form serves as the app’s graphical user interface. More information and an online screencast is available on our Tamarixia Tracker website if you’re interested in how it works. I selected FileMaker as our development platform for these reasons:
- FileMaker is a visual environment, so we modeled our database to mimic the appearance of the provided form;
- We developed for both Windows and Mac operating systems by coding one version of the database; ● Our app was ported to iPhone and iPad with minimal reformatting (Figure 5);
- We can generate real-time summary calculations and reports even as wasps are released. An example of a generated report is available on our website;
- The parent app can be scaled later as a web browser solution to accommodate broader participation;
- Data in the web application can be directly shared within the same collection between growers and researchers;
- Data can be exported into a variety of formats.
How you can participate in the Tamarixia Release Program The Tamarixia Release Program is looking for more growers to participate. You need to locate trees that are unmanaged, not sprayed with insecticides and that provide a suitable habitat for the wasp to thrive. Organic groves are also good candidate locations. Contact Dr. Robin Stuart at the Dundee Biological Control Laboratory at email@example.com (863-438-9222) and provide your name, company, release locations (GPS coordinates, if possible), and a brief description of the site (wild, abandoned, organic, etc.). Dr. Stuart should get back to you for coordinating your release. Participation is first-come, first-serve and depends on available supplies, but the program is scaling up to accommodate more people. Once again, you’ll have to agree to provide timely release data back to the lab.
How to obtain the Tamarixia Tracker App We need to emphasize that Tamarixia Tracker is not state-sponsored software, nor do they have an active role in its development. Instead, my software company designed the app for our own internal use. But it’s working well enough that others may benefit from it. If you’re interested, take a look at our screencast to see if it’s an app you’d like to use for tracking your Tamarixia releases. If so, contact me with information about your computer platform. Tamarixia Tracker runs on either Mac or Windows with FileMaker installed. A standalone desktop version for those without FileMaker is also available for Apple Mac desktop (Mavericks-compatible), iPhone and iPad. You need the desktop app to produce reports. We’re currently on Version 2.2 and if there’s sufficient interest (and sponsorship), we may consider scaling the app as a web application to make it available to everyone.
Our participation in the Tamarixia Release Program is an exciting development in our psyllid management program. It’s not an ultimate solution, but it’s one important tool in the arsenal. It’s greatest benefit may be several years away, but it’s non-chemical, it simplifies some aspects of psyllid management, and it’s an opportunity to use the latest mobile technologies to collect and share data between growers and researchers. The program’s chances of success are much greater with the more people that participate. Our effort in the program represents a serious investment in time and resources, so we designed our Tamarixia Tracker app to be an easy-to-use technology for efficiently tracking releases and immediately providing vital data to the state. And the quality of data shared with others this way will help ensure coverage in the most needed locations. The Tamarixia Release Program and our Tamarixia Tracker are real-world, real-results projects and we look forward to continuing our wasp releases and software development with the program.
Author disclaimer The information in this article is provided “as is”. The author and publisher of this article disclaim any loss or liability, either directly or indirectly, as a consequence of reading, disseminating, applying or using any mentioned information herein, or in the use or application of any mentioned technology for any purpose whatsoever. No guarantee is given, either expressed or implied, in regard to the accuracy, merchantability or acceptability of this information or technology.