Progress 09/01/03 to 08/31/06
Outputs
For our objective to develop treated targets for adult stable fly control, we conducted studies to determine the influence of weather, time, fabric type, insecticide type, and insecticide concentration on the mortality of stable flies from a susceptible laboratory colony exposed for 30 sec to treated targets. We found that 100% of the flies exposed to trigger targets that were treated with 0.1% lambdacyhalothrin or 0.1% zetacypermethrin and placed outdoors for up to three months were dead within 30 min of exposure. In a series of two experiments using electrocution techniques, a half blue and half black (UK) 1 m2 trigger target was determined to be acceptable for development studies. In the first experiment, an average of 350 stable flies per hr (maximum 794 flies in 1 hr) was collected using the UK target. A time-delayed circuit trial using untreated UK targets demonstrated that stable flies remained on or around the targets for at least 30 seconds. Two experiments
were conducted with time-delayed circuits and UK targets treated with 0.1% lambdacyhalothrin. The number of flies collected using the 30 sec on/off treated target treatment was not different from the number of flies collected using the other treatments. The number of flies collected with UK trigger targets was 6.1-fold higher than that for alsynite cylinder traps in two experiments. We evaluated the nematode S. feltiae SN as a biological control agent of stable fly larvae in the laboratory towards second and third instars using a filter paper assay. Six replicates of 15 larvae were inoculated with 25, 75, 150, and 300 nematodes per maggot. Probit analysis was used to calculate LC50 values; the LC50 was 106 nematodes for second instars and 32 nematodes for the third instar larvae. Nematodes successfully reproduced and infective juvenile nematodes emerged from the third instar larvae. Subsequently, field studies on larval stable fly control were conducted. Three different hay bale
residues (sites) each were partitioned into 12 approximately 1.2 m2 plots of which the central 1 m2 area was subsequently treated. There were 12 treatments: water, nematodes, and permethrin each applied in 4 different volumes (4, 8, 20 and 40 liters). Approximately 150,000 nematodes were applied in each volume. The permethrin was applied at .05 percent ai in all treatments. After treatments were applied, three 415 cm2 cylindrical emergence traps were placed in the center of each plot. The number of adult stable flies in each emergence trap was recorded three times per week for six weeks. Emergence was compared using ANOVA followed by Tukey's mean separation test. For all treatments, the number of flies emerging in permethrin treated plots (0.06 +/- 0.3 to 0.8 +/- 1.9) was significantly less than in the control plots (3.0 +/- 3.3 to 4.8 +/- 6.6) and the nematode treated plots (2.4 +/- 3.0 to 5.7 +/- 6.9). During the study, up to an estimated 4,511 to 5,347 adult stable flies per 1 m2
emerged from the water and nematode treated plots while less than 100 per 1 m2 emerged from the two highest volume permethrin treated plots.
Impacts
The virulence of the nematode S. feltiae SN towards third instar stable fly larvae appeared to be at a level that would allow control of stable flies, but the field applications were not effective. The results of this study indicated that application of permethrin to hay residues can greatly reduce the number of adult stable flies produced by these habitats. A single round hay bale residue can create a 10 m2 stable fly larval habitat which under the conditions of our study can generate over 50,000 adult stable flies over a 6 week period. The high dose permethrin treatments were shown to reduce the number of emerging stable fly adults by 99 percent. The results of this study also indicated that treated cloth targets may be a viable addition for stable fly control programs. It has been demonstrated that permethrin-treated Alsynite traps at a rate of one per five head of cattle at two sites in Florida provided a more than 30% reduction of a stable fly population. The
results of our trap comparison studies indicate that our targets will be much more effective than these traps, and that we should be able to achieve adult stable fly control with a reasonable and manageable number of targets. The data indicate that one treated target could have a potential to eliminate over 10,000 adult stable flies per day. Protecting growing cattle from moderate stable fly infestations has been shown to result in approximately 50 pounds of additional weight gain over a 100 day period, which could result in a sixty dollar difference per head in today's market.
Publications
- Foil, L., and J. Hogsette. Treated targets for stable fly control. Proc. XXII International Congress of Entomology. Brisbane, Australia. August 2004 p. 173.
- Foil, L.D. Control of mechanical transmission of agents of livestock diseases. Proc. First International Symposium on Hemoparasites and their Vectors. Caracas, Venezuela. October 2004 p. 46.
- Foil, L., and Younger, C. 2006. Development of treated targets for controlling stable flies (Diptera: Muscidae). Veterinary Parasitology. 137: 311-315.
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Progress 01/01/05 to 12/31/05
Outputs
An objective of this research was to evaluate the nematode S. feltiae SN as a biological control agent of stable fly larvae. Nematodes were reared using late-instar greater wax moths, Galleria mellonella. Nematodes were harvested with White traps, quantified by counting the number of nematodes in five, 5 microliter samples and diluted to the needed concentration. The nematode virulence towards second and third instar stable fly larvae was tested using a filter paper assay. The stable fly larvae were placed in a 9-cm Petri dish lined with a filter paper disk. Six replicates of 15 larvae were inoculated with 25, 75, 150, and 300 nematodes per maggot. Water was used as a control, and stable fly mortality observed at 3 d. Probit analysis was used to calculate LC50 and LC90 values for the filter paper bioassays. For the second instar stable fly larvae, the LC50 was 106 nematodes per host and for the third instar larvae, the LC50 was 32 nematodes per host. To determine if
the nematodes can reproduce in stable fly cadavers, dead second and third instar larvae were placed on White traps to see if any nematodes emerged. Nematodes successfully reproduced and infective juvenile nematodes emerged from the third instar larvae but none emerged from second instar larvae. The virulence of the nematode S. feltiae SN towards third instar stable fly larvae appears to be at a level that will allow control of stable flies in field applications. Electrocution techniques were used to determine if treated targets similar to those used for tsetse control could be developed for stable fly control. In a series of two experiments, a half blue and half black (UK) 1 m2 target constructed of trigger cotton poplin was determined to be acceptable for development studies. In the first experiment, an average of 350 stable flies per hr (maximum 794 flies in 1 hr) was collected using the UK target. A time-delayed circuit trial using untreated UK targets demonstrated that stable
flies remained on or around the targets for at least 30 seconds. Two experiments were conducted with time-delayed circuits and UK targets treated with 0.1% lambda-cyhalothrin. In the first experiment, the number of flies collected using the 30 sec on/off treated target treatment was not different from the number of flies collected using the other treatments. In the second experiment, the number of flies collected using the 30 sec on/off treated target treatment was not different than the untreated target continuous or 30 sec on/off treatments, but was significantly lower than the treated target continuous treatment. The number of flies collected with UK trigger targets was significantly higher than that for alsynite cylinder traps in two experiments. The mean number of flies collected during twenty-two 1 hr assays using targets was 6.1-fold higher than that for alsynite traps, and the mean number of flies collected during forty 3 hr using the targets also was 6.1-fold higher than that
for alsynite traps. The results of this study indicate that treated cloth targets may be a viable addition for stable fly control programs.
Impacts
The virulence of the nematode S. feltiae SN towards third instar stable fly larvae appears to be at a level that will allow control of stable flies in field applications. Natural reproduction of the nematodes in the larvae may help sustain nematode populations in the field and reduce the number of nematode applications required for control.When we determine the optimal application techniques in field studies, this will be the first viable control strategy for the round hay bale larval stable fly habitat.The results of the target study indicate that treated cloth targets may be a viable addition for stable fly control programs. It has been demonstrated that permethrin-treated Alsynite traps at a rate of one per five head of cattle at two sites in Florida provided a more than 30% reduction of a stable fly population. The results of our trap comparison studies indicate that our targets will be much more effective than these traps, and that we should be able to achieve
adult stable fly control with a reasonable and manageable number of targets. The data indicate that one treated target could have a potential to eliminate over 10,000 adult stable flies per day. Protecting growing cattle from moderate stable fly infestations has been shown to result in approximately 50 pounds of additional weight gain over a 100 day period, which could result in a sixty dollar difference per head.
Publications
- Foil, L., Younger, C. 2006. Development of treated targets for controlling stable flies (Diptera: Muscidae). Veterinary Parasitology. In Press.
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Progress 01/01/04 to 12/31/04
Outputs
An objective of this project is to evaluate the use of the nematode Steinernema feltiae strain SN for the biological control of stable fly larvae. Larval habitats were created by feeding round hay bales to cattle over a four week period at 3 sites. Two 1m2 plots were selected at each of the sites and treatment was assigned by coin toss. Control plots were treated with 4 liters of water and the treatment plots received 4 liters of water containing approximately 44,400 nematodes. Three emergence traps were placed on each plot, and flies were collected daily for three weeks. Throughout the post-treatment period, the average number of emerging stable flies was 13.9 and 6.7 for the control and treated areas, respectively. We also propose to develop insecticide treated targets for adult stable fly control. We conducted studies to determine the influence of weather, time, fabric type, insecticide type and insecticide concentration on the mortality of stable flies from a
susceptible laboratory colony exposed for 30 seconds to treated targets. Our standard polyester and cotton mix cloth was treated with three concentrations (0.0, 0.5 and 1.0 %) of lamdacyhalothrin and one concentration (0.1%) of zetacypermethrin (EC), zetacypermethrin (EW), cypermethrin (EC), and permethrin (EC). We also treated the mix, cotton and cotton canvas with 0.1% lambdacyhalothrin. A sample of each treatment was stored inside and outdoors in Gainesville, FL, for three months. An assay was conducted for each treatment at day 1 and then once per month. After three months outside, 100% of the flies exposed to the three concentrations of lambdacyhalothrin and zetacypermethrin (EC) were dead within 30 minutes of exposure, but this was not the case for the other insecticide treatments. The same result was observed for the mix fabric, but none of the other three fabric types. If insecticide impregnated targets are developed for stable fly control, we need to make certain that the
insecticides do not repel flies. In 2003, we treated two targets with 0.1% lamdacyhalothrin and compared them to an untreated target. One treated target and the untreated target were placed in electric grids that were run continuously and the other treated target grid was run at a 30 second on and 30 second off cycle. No difference in catch was observed; the mean number of flies collected per hour was 134.9 for the untreated target, 134.0 for the treated-continuous, and 101.2 for the treated-cycle. In 2004, we treated two targets with 0.1% lamdacyhalothrin and compared them to two untreated targets. One treated target and one untreated target were placed in electric grids that were run continuously and the other treated and untreated target grids were run at a 30 second on and 30 second off cycle. The targets were placed in each of 4 sites on 4 occasions. No statistical difference in catch was observed; the mean number of flies collected per hour was 274 for the untreated
target-continuous, 209 for the untreated-cycle, 331 for the treated-continuous, and 171 for the treated-cycle.
Impacts
The stable fly has emerged as a major livestock pest in Louisiana and this is the first study to show that we will be able to develop control programs for this pest. Preliminary studies indicate that entomopathogenic nematodes may have a potential use for controlling larval stable fly populations in the pasture environment. We should be able to achieve adult stable fly control with a reasonable and manageable number of targets. We have demonstrated that treated targets can be effective for killing stable flies that land on them over a 3 month period, which should span the time of peak stable fly season at any geographic location in the United States.
Publications
- Foil, L., and J. Hogsette. Treated targets for stable fly control. Proc. XXII International Congress of Entomology. Brisbane, Australia. August 2004 p. 173.
- Foil, L.D. Control of mechanical transmission of agents of livestock diseases. Proc.First International Symposium on Hemoparasites and their Vectors. Caracas, Venezuela. October 2004 p 46.
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Progress 01/01/03 to 12/31/03
Outputs
An objective of this project is to develop insecticide treated targets for adult stable fly control. We conducted studies to determine the influence of weather, time, fabric type, insecticide type and insecticide concentration on the mortality of stable flies from a susceptible laboratory colony exposed for 30 seconds to treated targets. Our standard polyester and cotton mix cloth was treated with three concentrations (0.0, 0.5 and 1.0 %) of lamdacyhalothrin and one concentration (0.1%) of zetacypermethrin (EC), zetacypermethrin (EW), cypermethrin (EC), and permethrin (EC). We also treated the mix, cotton and cotton canvas with 0.1% lambdacyhalothrin. A sample of each treatment was stored inside and outdoors in Gainesville, FL, for three months. An assay was conducted for each treatment at day 1 and then once per month. After three months outside, 100% of the flies exposed to the all three concentrations of lambdacyhalothrin and zetacypermethrin (EC) were dead within
30 minutes of exposure, but this was not the case for the other insecticide treatments. The same result was observed for the mix fabric, but none of the other three fabric types. The daily capture of sticky Alsynite (Broce) traps was compared to the catch of Nzi traps made of two different types of cloth (cotton and polyester). We compared the Broce trap to the two Nzi traps in a 3X3 Latin Square design repeated 3 times at 3 sites. The mean number of flies per trap were 222.9 for the Broce, 125.1 for the polyester Nzi, and 257.9 for the cotton Nzi.; the average number of stable flies per trap per day was not significantly different. We compared the Nzi to an electric 1 m square 50% blue-50% black (UK) target, and the capture on the target was approximately twice that of the Nzi. In one study, the mean hourly catch for a UK target for 9 one-hr assays was 527 with a maximum of 1,335 per hour. That is, our targets could have a potential to eliminate over 10,000 adult stable flies per
day. If insecticide impregnated targets are developed for stable fly control, we need to make certain that the insecticides to not repel flies. We treated two UK targets with 0.1% lamdacyhalothrin and compared them to an untreated target. One treated target and the untreated target were placed in electric grids that were run continuously, and the other treated target grid was run at a 30 second on and 30 second off cycle. The targets were placed in each of 3 sites on 4 occasions. No difference in catch was observed; the mean number of flies collected per hour was 134.9 for the untreated target, 134.0 for the treated-continuous, and 101.2 for the treated-cycle. This study will be repeated, but it does not appear that the treated targets will be repellent for stable flies. We also compared the relative efficacy of different fabric types (cotton, dark polyester, light polyester and a cotton-polyester mix) as potential targets. The mean number of flies per target per hour was not
significantly different; 63.7 for cotton, 44.4 for dark polyester, 70.3 for light polyester, and 84.3 for mix.
Impacts
It has been demonstrated that permethrin-treated Alsynite traps at a rate of one per five head of cattle at two sites in Florida provided a more than 30% reduction of a stable fly population. Because our targets will be much more effective than these traps, we should be able to achieve adult stable fly control with a reasonable and manageable number of targets. We have demonstrated that treated targets can be effective for killing stable flies that land on them over a 3 month period, which should span the time of peak stable fly season at any geographic location in the United States.
Publications
- No publications reported this period
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