Provided by Dr. Marion Fuller
Florida Department of Agriculture and Consumer Services (FDACS)
Report Dated 06/19/98
Ground treatment in buffered areas is ongoing, as is fruit stripping in the core by commercial crews.
Sterile Release: As many of you are aware, we have been releasing sterile flies in Miami Springs for several months. We are currently releasing approximately 15 million/week in this program.
In addition to the Miami release, we are currently releasing around 200 million flies weekly, in association with the Bradenton program. The following are the approximate boundaries of the sterile release area:
Sterile flies are not being dropped over the 40 square mile aerial treatment zone, with the exception of an area of about 9 square miles of overlap. According to USDA, this overlap may result in an estimated loss of about 6% of dropped flies on the day of treatment. The 200 million flies are dropped over a period of seven days - with releases each day, totaling 200 million/week.
Beginning next week, we expect to begin releasing about 300 million flies weekly. The additional flies will be released over the greater Tampa area - north to the Pasco County Line, west to the Pinellas County line, east to I-75, with an excursion further east of I-75 to include Brandon and Thonotasassa.
Sterile flies are an excellent prevention tool, and can also be an effective eradication tool, if the host population of wild flies is relatively small, and not expanding rapidly. As an eradication tool, while effective under those conditions, it does take longer. The goal is to have sterile males mating with wild females - so that she lays infertile eggs, eliminating progeny. However, the sterile males are not necessarily as competitive as the wild males, and apparently wild females can tell the difference between the two, showing a preference for the wild males. For these reasons, it's important to have a very high ratio of sterile males to wild females, such that the odds of a wild female pairing with a wild male are very small.
(Note: These are the facts as I understand them.)
Environmental Monitoring: No report
Note: We have been experiencing problems with some of our analytical equipment - thus the delay in reporting the results from the samples collected after the first aerial bait treatment, along with the post application samples from Umatilla. We expect to have the problem resolved by early next week. All samples have been extracted, and will be analyzed well within our designated holding times.
We have had several reports of fish kills, yesterday and today (a total of 3 or 4 sites) - both within the treatment area and outside the treatment area. USDA is investigating the incidents within the treatment area, and as well as any that may occur nearby. Fish kills reported well beyond the treatment zone are being referred to local/regional environmental agencies.
Health Monitoring: No report
Note: I had several questions regarding my reference to the "corn bait" in yesterday's report from the Health Advisory Committee. The malathion-bait mixture being used (aerial and ground) is composed of 2.4 oz malathion and 9.6 oz of a corn - protein syrup or "bait". This is an attractive food source for the fly, which ingests the malathion-bait and dies. Proteins may be primary irritants, as well as causing allergic responses. If a person exhibits an irritant or allergic response to the malathion-bait, the causative agent could be either the bait itself or the malathion.
USDA received approval today for four ground bait treatments in a half square mile surrounding this fly find. Treatment is scheduled to begin Monday. There will be an announcement in the local paper Saturday, 6/20. In keeping with previous protocols, any homeowners in the treated area will be contacted at least 24 hours prior to the application.
Environmental Monitoring: These results are from samples collected Friday, June 12, prior to the seventh aerial bait treatment:
| Enola | BDL |
| Umatilla | BDL |
| Gibson | BDL |
| So Twin | BDL |
| East Lake | BDL |
| Bay | 0.1 - 0.3 ppb (between the MDL and PQL) |
| Yale | BDL |
| Crescent | BDL |
| Palm | BDL |
| Geneva | BDL |
Malaoxon was not detected in any sample (MDL = 0.1 ppb)
The minimum detection limit and practical quantitation limit remain at 0.1 and 0.3 ppb respectively.
Health monitoring: No report
NOTE: Several of you have asked whether we are also analyzing formulation samples. We are. These generally take longer to run; however, I have do have some results to report. We are taking samples from the bulk storage tank which is used to make up the malathion-bait mixture, each week, prior to aerial treatment. Because I have only partial results from the earlier samples, I will report those in a later update. We have the analytical capability to look for malathion, isomalathion and malaoxon in the malathion (Fyfanon) product. Because of the complexities and interferences associated with the bait-mixture, we are only able to analyze for malathion in that matrix.
The following are Fyfanon product formulation samples, taken from the bulk tank, at the Umatilla airport, before each application.
| 5/11 | Malathion | 95.5% |
| Isomalthion | 0.08% | |
| Malaoxon | BDL (MDL - 100 ppm) | |
| 5/15 | Malathion | 94.7% |
| Isomalthion | 0.09% | |
| Malaoxon | BDL (MDL - 100 ppm) | |
| 5/19 | Malathion | 94.6% |
| Isomalthion | 0.10% | |
| Malaoxon | BDL (MDL - 100 ppm) | |
| 5/23 | Malathion | 94.2% |
| Isomalthion | 0.10% | |
| Malaoxon | BDL (MDL - 100 ppm) | |
| 5/30 | Malathion | 96.6% |
| Isomalthion | 0.11% | |
| Malaoxon | BDL (MDL - 100 ppm) |
All results are within acceptable limits (in compliance with the registered product specifications).
The following results are from samples taken of the malathion bait mixture. (Recall this should be approximately a 20% mixture)
| 5/1 | 20.4% |
| 5/3 | 20.0% |
| 5/5 | 19.4% |
| 5/11 | 20.2% |
| 5/16 | 20.2% |
| 5/19 | 19.4% |
| 5/23 | 19.6% |
| 5/30 | 19.5% |
| 6/06 | 17.5% |
| 6/10 | 24.2% |
| 6/13 | 19.9% |
NOTE: Bradenton samples are pending - they will be reported as soon as they're available.
Thank you all for your continued assistance. Thanks also USDA - I have just received several pages of their data from the Umatilla sampling. I'll report these out next week. As always, I appreciate everyone's suggestions, comments, questions etc.
FDACS - Division of Plant Industy:
Mediterranean fruit fly information
USDA APHIS: Mediterranean fruit fly information
UF/IFAS Fact Sheet ENY-809:
The Mediterranean Fruit Fly
UF/IFAS Fact Sheet ENY-626:
Mediterranean Fruit Fly: What Floridians Need To Know