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Auxin herbicide drift to susceptible soybean [Glycine max (L.) Merr.] and cotton (Gossypium hirsutum) cultivars are a significant concern. Additionally, the impact of auxin herbicide drift on pollinators' foraging sources, including soybean, needs to be understood. A field experiment was conducted in 2022 at the University of Arkansas at Pine Bluff Small Farm Outreach Center near Lonoke, Ark., to evaluate the effect of auxin herbicide simulated drift rates on soybean reproductive organs (flowers and pods), pollen grains, and grain yield. A randomized complete block design was implemented with 8 replications. Four herbicides [florpyrauxifen-benzyl (Loyant®), 2,4-D (Enlist® One), dicamba (Engenia®), and quinclorac (Facet®)] were used at 2 rates (1/100x and 1/1000x the labeled rate) except for quinclorac, applied only at 1/100x the labeled rate. Four random soybean plants were collected from each treatment at the R3 growth stage, and reproductive organs were counted. Soybean flowers were also collected for pollen quantification 1 d before anthesis, and soybean was harvested at physiological maturity. Results showed that simulated drift rates of dicamba and florpyrauxifen-benzyl decreased the total number of soybean reproductive organs, pollen grains, and grain yield compared to the untreated control. Dicamba and florpyrauxifen-benzyl applied at 1/100x of the labeled rate reduced the number of reproductive organs by 35% and 39% at R3 compared to the nontreated control. Dicamba and florpyrauxifen-benzyl applied at this rate decreased pollen grains produced per anther by 28% and 18%, respectively, compared to the nontreated control. Applications of dicamba and florpyrauxifen-benzyl at 1/100x of the labeled rate reduced soybean grain yield by 43% and 27%, respectively, compared to the nontreated control. In addition to grain yield reduction, these results show that simulated auxin herbicide drift rates negatively impact pollinators' foraging sources with decreased pollen grain production and reducing the total number of reproductive organs, further illustrating the need for drift mitigation strategies to be developed and implemented. [ABSTRACT FROM AUTHOR]

Insecticide efficacy often varies by location and year. Many factors can influence an insecticide's efficacy, but an often-overlooked factor is water quality in a carrier solution. Multiple experiments were conducted to evaluate the impact of water hardness and pH on chlorantraniliprole efficacy for controlling corn earworms. In the first experiment, leaf dip assays were conducted to evaluate the effects of water pH on chlorantraniliprole. Serial dilutions were used to achieve the concentration of 6 ng/mL of chlorantraniliprole in 3 different water samples with a pH of 6.47, 8.31, and 9.12, respectively. Larvae were placed on 0.5-in. leaf discs after drying and observed for mortality 48 hours after application. In the next experiment, leaf dip assays were conducted similarly but with water at a hardness of 11 ppm, 178 ppm, and 430 ppm, respectively. A third experiment was conducted in the greenhouse where Prevathon® at a rate of 14 oz/ac was mixed with water with a hardness of 10.9 ppm, 178 ppm, and 430 ppm, respectively, then applied to soybean plants. Leaves were pulled from the soybean plants at 1, 7, 21, 28, and 35 days. Larvae were placed on 0.5 in. leaf discs and checked for mortality at 48 hours. In the final experiment, water samples with a hardness of 10.9 ppm, 178 ppm, and 430 ppm, respectively, were mixed with Vantacor® 1.2 oz/ac, Intrepid Edge® 5 oz/ac, Denim® 8 oz/ac, and Besiege® 7 oz/ac then sprayed on soybeans and evaluated at 4, 7, and 10 days after treatment for the control of corn earworm. The hardness leaf dips and pH leaf dips showed that as water hardness or pH increased, the % mortality decreased. In the greenhouse and field trials, there were no significant differences. [ABSTRACT FROM AUTHOR]

Insecticide efficacy often varies by location and year. Many factors can influence an insecticide's efficacy, but an often-overlooked factor is the quality of water in a carrier solution. Multiple experiments were conducted to evaluate the impact of water quality on insecticide efficacy. In the first experiment, leaf dip assays were conducted with Transform, Orthene, Bidrin, and Centric, each mixed in three waters with hardness levels of 10.9, 178, and 430 ppm. Transform, Orthene, Bidrin, and Centric were also mixed in three waters having pHs of 6.47, 8.03, or 9.27, with an untreated check. Adult plant bugs were placed on a one-half-inch leaf disc after drying, and mortality was observed at 48 hours. In the second experiment, Transform 1.5 oz/ac, Orthene 0.75 lb/ac, Bidrin 8 oz/ac, and Centric 2 oz/ac were each mixed in three waters with hardness levels of 10.9, 178, and 430 ppm, then applied to cotton for tarnished plant bug control. In the third experiment, Transform 1.5 oz/ac, Orthene 0.75 lb/ac, Bidrin 8 oz/ac, and Centric 2 oz/ac were each mixed in three waters with pHs of 6.47, 8.03, and 9.27, then applied to cotton and evaluated for tarnished plant bug control. In the fourth experiment, Bidrin was mixed with waters with a pH of 6.4 and 9.1. AMS, Quest, Smoke, Diversify, and an experimental compound were each added to water with a pH of 9.1 prior to the addition of Bidrin, then applied to cotton. In the fifth experiment, Bidrin was mixed with water having a hardness of 10.9 ppm (soft water) or 430 ppm (hard water). AMS, Quest, Smoke, Diversify, and an experimental compound were each added to water with a hardness of 430 ppm, Bidrin was then added, and the solutions were then applied to cotton. No differences in treatments were present in the first, second, or third experiments. In the fourth experiment, the experimental compound and Quest provided better control than Smoke at 4 days after treatment (DAT). At 7 DAT, Smoke continued to provide the poorest control. In the fifth experiment, there were no differences at 3 DAT, but at 7 DAT, Diversify provided better control than the soft water. [ABSTRACT FROM AUTHOR]

Experiments were conducted from 2020-2022 to evaluate effectiveness of insecticides and application methods for control of rice billbug. An insecticide seed treatment study was conducted using neonicotinoid and diamide insecticide seed treatments alone and in conjunction with one another to assess potential suppression of rice billbug injury. Additionally, a study was conducted to observe if foliar insecticide applications could suppress rice billbug. Multiple sampling methods were tested to correlate rice billbug damage to grain yield. At the panicle initiation growth stage, rice was sampled by counting total tillers and damaged tillers in five linear feet per plot. After panicle emergence, the number of blank heads per five linear feet within a plot was also recorded. Sampling rice prior to heading shows a general trend between treatments, but optimal timing needs to be evaluated. In the insecticide seed treatment study, a general trend was observed. Plots with a seed treatment containing a neonicotinoid in combination with a diamide product, resulted in yields greater than the untreated check or any single chemistry insecticide seed treatment. Rice seed treated with only a diamide resulted in greater yields when compared to a neonicotinoid treatment. Finally, no differences were observed when two neonicotinoids were applied to rice seed compared to a single neonicotinoid alone. All insecticide seed treatments significantly increased yield when compared to the untreated check. Results from the foliar insecticide study showed that greatest yields were observed with a combination seed treatment compared to any foliar insecticide applied regardless of timing. [ABSTRACT FROM AUTHOR]

The utilization of semiochemicals such as insect pheromones has proven successful in monitoring regimes for U.S. agriculture in the last half-century. The rice billbug, (Sphenophorus pertinax, Chittenden), has recently become a concern to mid-Southern U.S. rice producers implementing a potential cost-saving, production system. Furrow-irrigated rice hectare has continued to increase for the last five years. Lack of research on the rice billbug has raised concerns as the furrowirrigated rice system gains popularity. Further understanding, and evaluations of control tactics have become a priority for entomologists in rice-growing regions of the U.S. Extraction and implementation of pheromone targeted for rice billbug, could allow timely control measures to take place and potentially reduce the amount of injured rice across the field. In this study, volatile semiochemicals extraction, and Y-tube choice tests were conducted at the University of Arkansas System Division of Agriculture's Department of Entomology in Fayetteville, Ark. Volatiles were extracted from rice billbug populations caught during the 2021 and 2022 growing season across the state of Arkansas. Three different chemicals (volatiles and closely related compounds) were evaluated for their attractancy to male and female rice billbugs. Findings from these preliminary studies show that a significant response to tested semiochemicals was observed. Blends A (4-Methyl-2-pentanol) and B (2,6-Dimethyl-4-heptanol) were more frequently selected compared to blend C containing tert-Butyl hydroperoxide. Blend C also suggested signs of repellency in males, and higher attraction in females. However, further research is needed in this direction as developing a semiochemical-based effective monitoring regime could potentially aid growers in economically and efficiently controlling rice billbug in future crops. [ABSTRACT FROM AUTHOR]