Progress 09/01/21 to 08/31/24

Outputs
Target Audience:Through the project collaborators' agriculture extension services at the University of Arkansas and Univrsity of Nebraska, livestock producers have becomeinformed about new developments for fly/insect control that provide alternatives to traditional pesticides. One such alternative is the project at hand to develop formlations of naturally occurring fatty acids that can potentially be used for organic production. To that end, an application has been filed and approved by the Organic Materials Research Institute (OMRI) to have our formulation (XPS-205) listed for organic production. Since XPS-205 is regulated by US EPA, its registration is necssary in order to get the product in thehands of users, sowe have assembled a data package,to include an amended tolerance exemption for inerts. With the completion of one efficacy study in the spring of 2025, the application will be submitted to the Agency. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest?Two presentations at the Livestock Insect Workers Conference were made in 2024 as follows: "Formulation of a Fatty Acid Emulsifiabe Concentrate as a Biopesticide for Livestock Fly Control", William G. Reifenrath, Stratacor, Inc. Novato, CA and Kelly M. Loftin, University of Arkansas, Fayetteville, AR "Field Testing a Free fatty Acid (FFA) Formultion Concentrate for Livestock Fly Control", Kelly M. Loftin and Elizabeth Smith, University of Arkansas, Fayetteville, AR and William G Reifenrath, Stratacor,Inc., Novato, CA What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? While medium chain fatty acids (octanoic, nonanoic and decanoic acids called C8910) are generally regarded as safe (GRAS), they have contact insecticidal activities against certain insects and arthropods. This activity can be increased by increasing the dose, but higher doses can result in greater potential for skin and eye irritation when exposed to mammals and increased phytotoxicity when exposed to plants. This study was undertaken to increase the pesticidal potency of the fatty acids by formulation in aqueous emulsion along with adjuvant. We focused on emulsions of a 2 component mix of octanoic and decanoic acids (C8C10) as actives, since a C8C10 formulation was successfully registered with OMRI for organic production. The inclusion of a proprietary adjuvant with the C8C10 formulations increased pesticidal performance and residual activity. While the adjuvant had no known pesticidal activity by itself, and lab tests with 1% adjuvant in distilled water showed little or no insecticidal effect, lab tests with house flies, stable flies, and horn flies demonstrated that insect incapacitation was more rapid and mortality (incapacitation at 24 hours post treatment) was significantly higher when the adjuvant was present in the fatty acid formulation. Performance against permethrin resistant stable and horn flies was also increased. A University of Arkansas field study evaluated C8C10 in automated sprayers with and without adjuvant versus horn flies on pastured cattle. The addition of adjuvant (formulation No. XPS-144) gave more rapid fly control compared to the fatty acids alone (XPS-143); XPS-144 had equivalent efficacy to permethrin/PBO during the spray period (94-98% control), but with greater residual efficacy. A similar study in the central valley of California, using manual sprayers, demonstrated greater residual efficacy when the adjuvant was present, maintaining horn fly numbers at about 100/animal, well below the economic injury threshold . These results demonstrated that good fly control can be provided with C8C10 formulations with adjuvant, whether used in manual sprayers or in an automated device. Further studies were conducted at the University of Arkansas facilities near Fayetteville, AR over a 2 year period of time (2022-2023 summer months). Fatty acid concentrate was diluted with water to 0.5% and 1.0% free fatty acids levels and applied with an automated sprayer ( 3-D Quik Hand, 3-D Cattle Equipment , LLC, Pine Ridge, AR) at daily intervals vs. every 2nd day (year 1, trial 1) and every 3rd day (year 1, trial 2). These trials showed that a 1% FFA aqueous dilution of concentrate formulation can be successfully applied to cattle using an automated sprayer that allowed for multiple applications of a small volume (200-300 ml) of spray solution. Both trials showed success at reducing horn fly populations below the economic threshold of cattle at 200 flies per head for cattle. In addition, less frequent applications (every other day or every third day) can maintain fly abundance under the 200 flies per animal economic threshold. The year 2, trial 1 study showed that 0.5% and 1.0% FFA provided equal fly control that was significantly superior to untreated control. The year 2, trial 2 (7 day trial) and trial 3 (22 day trial) studies showed that fly control for 0.5% FFA and 0.05% Permethrin/0.05% PBO were not significantly different; both treatments provided fly control superior to untreated control. Similar studies were conducted at the University of Nebraska North Platte Extension Center vs. horn flies and stable flies In the 2021 season, XPS-203 (about 3% actives) was diluted to 0.25%, 0.5%. 0.75% and 1%. While all concentrations decreased mean horn fly numbers below the EIL, the best results were obtained at the 1% concentration. Stable fly control was suboptimal due the poor coverage of the lower area of the cattle, resulting in a reposition of spray nozzles for the 2022 season. With this modification, the efficacy of dilutions of XPS-205 (5% actives) resulted in significant reductions of horn flies, stable flies, and face flies, with reductions comparable to permethrin positive control. Due to circumstances beyond our control in test seasons 2022-4 (lack of flies or horses), only preliminary data could be obtained for stable fly control on horses. An additional study is planned at the University of Arkansas in the spring of 2025. Acute toxocilogy testing (skin and eye irritation and oral LD50) placed XPs-205 in Category III. Product chemistry and accelerated storage stability of XPS-205 showed the actives to be stable. In anticipation of EPA registration, a waiver of tolerance petition for the adjuvant in XPS-205 was prepared in addition to waivers of tolerance petitions for the surfactants contained in the formulation. A new application was granted for XPS-205 with OMRI for organic production. In conclusion, studies showed that XPS-205 is a stable, safe, and effective formulation for livestock fly control on cattle that is economical and compatible with organic production.Aqueous dilutions of this FFA concentrate can provide a practical alternative to permethrin based products for horn fly control on cattle.

Publications

Progress 09/01/22 to 08/31/23

Outputs
Target Audience:Through the project collaborators' agriculture extension services at the University of Arkansas and University of Nebraska, livestock producers have become informed about new developments for fly/insect control that provide alternatives to traditional pesticides. One such alternative is the project at hand to develop formulations of naturally occurring fatty acids that can be used for organic production. To that end, an aaplication has been granted by the Organic Materials Research Institute (OMRI) to have XPS-205 listed for organic producton. Since XPS-205 is regulated by the US EPA, its registration is necessary to get the product in the hands of users, so efforts are underway to submit a data package for registration with the Agency. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals?During the next and final reporting period, we will complete the evaluations of of XPS-215 and dilute XPS-205 (3.7%) for efficacy on horses (stable fly and face fly). We plan to complete EPA registration of XPS-205 and finalize an agreement for commercial sales with industrial partner(s).

Impacts
What was accomplished under these goals? Octanoic and decanoic acids, at a ratio of approximately 60/40 respectively, were formulated (XPS-205) in an aqueous emulsion concentrate (EC) at a level of 5.0% total unionized or free fatty acids (FFA). Using an automated sprayer, beef cattle were treated with aqueous dilutions of the EC in the range of 0.5-1.0% FFA. In North Platte, Nebraska field trials conducted in the summer of 2022, the efficacy of dilute XPS-205 was evaluated vs. horn flies, stable flies and face flies. Overall, dilute XPS-205 treatments resulted in significant reductions of these flies in comparison to untreated controls, with reductions comparable to permethrin positive control (Pyranha, 0.05%). Similar field trials in Arkansas in the summer of 2022 showed success in reducing horn fly populations below the economic threshold (200 flies per head) for a 0.5% dilution of XPS-205; every third day applications maintained horn fly numbers below 200/head. Preliminary results in the 2023 fly season showed that XPS-203 (an aqueous dilution of XPS-205 to 3.7% FFA), as well as a 15% FFA formulation (XPS-215) were capable of reducing stable flies and face flies on horses. No adverse effects were seen in the Nebraska and Arkansas field trials. GLP toxicological evaluations (Stillmeadow, Sugar Land, TX) of undiluted XPS-205 (5% FFA) were conducted. An acute oral toxicity study in rats showed no mortality and no clinical signs of toxicity, consistent with previous observations that octanoic and decanoic acids are not systemically toxic. The acute oral LD50 (rat) was determined to be >5,000 mg/kg. A skin irritation in the rabbit rated XPS-205 as slightly irritating (Toxicity Category IV). An eye irritation study in the rabbit rated XPS-205 as mildly irritating (Toxicity Category III). Product chemistry and accelerated storage stability of XPS-205 showed that the actives were stable. In anticipation of EPA registration, a waiver of tolerance petition for the adjuvant in XPS-205 was prepared in 2003, in addition to waivers of tolerance petitions for the surfactants contained in the formulation. A new application has been granted for XPS-205 with OMRI for organic production. In conclusion, studies showed that XPS-205 is a stable, safe, and effective formulation for livestock fly control that is economical and compatible with organic production.

Publications

Progress 09/01/21 to 08/31/22

Outputs
Target Audience:Through the project collaborators' agriculture extension services at the University of Arkansas and University of Nebraska, livestock producers have become informed about new developments for fly/insect control that provide alternatives to traditional pesticides. One such alternative is the project at hand to develop formulations of naturally occurring fatty acids that can potentially be used for organic production. To that end, an application has been filed with the Organic Materials Research Institute (OMRI) to have our formulation (XPS-205) listed for organic production. Since XPS-205 is regulated by US EPA, its registration is ncecessary in order to get the product in the hands of users, so we have initiated efforts to assemle a data package for registration with the Agency. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Nothing Reported How have the results been disseminated to communities of interest?Through the project collaborators' agriculture extension services at the University of Arkansas and University of Nebraska, livestock producers have become informed about new developments for fly/insect control that provide alternatives to traditional pesticides. One such alternative is the project at hand to develop formulations of naturally occurring fatty acids that can potentially be used for organic production. To that end, an application has been filed with the Organic Materials Research Institute (OMRI) to have our formulation (XPS-205) listed for organic production. Since XPS-205 is regulated by US EPA, its registration is ncecessary in order to get the product in the hands of users, so we have initiated efforts to assemle a data package for registration with the Agency. What do you plan to do during the next reporting period to accomplish the goals?During the next reporting period (year 2 of Phase II), field studies with cattle will involve dilute applications of XPS-205, a 5% concentrate of octanoic and decanoic acids as actives,using an automatic sprayer (3-D Quik Hand Cattle Sprayer, 3-D Cattle equipment, Pine Ridge Arkansas). The actives level in the aqueous dilutions will be at 0.5 or 1.0%, pending analysis of Phase I results. The study procedures in Year 2 will be identical to Year 1 except the best active concentration and appcation freqency combination from Year 1 will be tested in a season long study at Arkansas and compared to a positive ontrol (permethrin) applied at 0.05%. A 3 week study, using the same application frequency and actives concentration, will be conducted at the University of Nebraska, again in comparison to the permetrin positive control. A 15% fatty acid actives concentration formulation will be evaluated on horses at the University of Nebraska, with the Year 1 study to be completed in the fall of 2022 (Year I) and Year 2 study completed in the spring of 2023. Application of all treatments will be made using a small hand-held pump sprayer and a wipe-on, using a glove. Spray applictions will be direct to the top line, sides, belly region and neck area while applicaions to th facila area will be made with a gloved hand o avoid contact with the horse's eyes, mouth, and nostrils. A pre-treatment stable fly count will be rorded prior to the application of products (15% Fatty acid formulation vs permethrin). Post-treatment fly counts will occur at 1,2,4,6,24,48, and 72 hours post-treatment. The application rate will be determned in Year 1 with the initial application rate based on Arkansas spray rate for cattle. Year 2 will be a 3-week study (3 applications per week) using a single application rate found mosst effective in Year 1. Procedures used in Year 1 will be followed in Year 2. Finally, a registration package (product chemistry, efficacy, storage stability)will be assembled in Year 2 for submission to US EPA for XPS-205 and we expect to have technical review (OMRI) completed for organic production.

Impacts
What was accomplished under these goals? While naturally derived medium chain fatty acids (octanoic, and decanoic acids called C810) are generally regarded as safe (GRAS), they have contact insecticidal activities against certain insects and arthropods. This activity can be increased by increasing the dose, but higher doses can result in greater potential for skin and eye irritation when exposed to mammals and increased phytotoxicity when exposed to plants. This study was undertaken to increase the pesticidal potency of the fatty acids by formulation in aqueous emulsion along with adjuvant. Laboratory studies in Phase I demonstrated pesticidal enhancement by the adjuvant with sensitive and resistant stable and horn flies, house flies and cockroaches. In Phase II, laboratory studies further demonstrated the adjuvant's effect with mosquitoes (Culex quinquefasciatus) and separate studies with fatty acid/adjuvant formulations showed inhibition of egg deposition with stable flies. Phase I field studies conducted in California and Arkansas confirmed the beneficial effects of the adjuvant vs. horn flies. In Phase II, field studies at the University of Arkansas (2021 season) evaluated the C8C10/Adjuvant emulsifiable concentrate formulation (XPS-203, 3.7% fatty acid actives) diluted to a ready to use preparation or RTU, which was 1% actives and 1% adjuvant (equivalent to XPS-144 formulation tested in Phase I). Testing was done with automated sprayers with small volumes of formulation (200-300 ml) to look at treatment interval (daily, every othe dray, and every 3rd day) for horn fly control on pastured cattle. Horn fly numbers were reduced below the economic threshold of cattle (200 flies/head) for all treatment intervals. Overall percent control was higher for the every 3rd day interval, which may be due to a residual effect from previous trials. Field studies at the University of Nebraska (2021 season) tested several dilutions of XPS-203 (1%, 0.75%, 0.5% and 0.25%) in an identical automated sprayer for horn fly and stable fly control on cattle. While all concentrations decreased mean horn fly numbers below the economic injury level (EIL, 200 flies/head), the best results were obtained at the 1% concentration, which reduced fly numbers to 50-70/head, well below the EIL. Stable fly control was sub-optimal because the spray pattern did not reach the lower regions of the cattle, where the stable flies feed. The addition of a 4th nozzleand repositioning of the nozzles led to improved lower animal coverage. These changes will improve stable fly control and may lower the active's concentration for both horn fly and stabe fly control.Preliminary 2022 season test results from the University of Arkansas with th four nozzl sprayer configration indicated that a 10-fold dilution of XPS-205 to a level of 0.5% actives may still be adequate for horn fly control on cattle. Preliminary test results from the University of Nebraska with the 4 nozzle configuration indicatedthat a minimum application frequency of twice per week is necessary for horn fly control on cattle when applying XPS-205 or permethrin from the automatic sprayers. Laboratory studies have shown that the emulsifiable concentrate actives (3.7% in XPS-203) can be increased to 5% (XPS-205) and this formulation will be used in the 2022 field studies with cattle at Arkansas and Nebraska. Horse owners provided user evaluations of several concentrations (1.0, 5.0 and 15%) of C810 fatty acids in aqueous emulsion. Their preference was for a repellent effect (predominant at higher concentration ) over an insecticidal effect (<1% concentration). The 15% concentration was well tolerated by the horses (no irritation) and this formulation will be tested for efficacy at the University of Nebraska in the fall of 2022. In conclusion, the field study results demonstrated that good horn fly control can be provided with C8C10 formulations with adjuvant, when used in an automated device.We expect that changes made in the automated spray pattern, made prior to the upcoming 2022 test season, will improve both stable and horn fly control. .

Publications