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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]

Tobacco thrips are one of the most important pests in mid-South cotton production. Thrips are a pest of seedling cotton, feeding on the leaf tissue of plants which can result in stunted growth, delayed fruiting, loss of apical dominance, and possible stand loss. Field studies were conducted in 2021 and 2022 to evaluate ThryvOn, a new transgenic trait in cotton that produces the Bt toxin Cry51Aa, for control of tobacco thrips. ThryvOn cotton was tested at three Arkansas locations, Marianna, Tillar, and Keiser. The trials evaluated thrips control on ThryvOn vs. non-ThryvOn cotton and the effect of insecticide seed treatments on ThryvOn cotton. ThryvOn cotton had significantly fewer thrips and less injury than non-ThryvOn cotton. Results from this study indicate that ThryvOn has the potential to be a valuable tool for thrips management. [ABSTRACT FROM AUTHOR]

Bollworm (Helicoverpa zea, Bodie) is currently the second most damaging insect pest of cotton in Arkansas. The primary method used to control bollworms in cotton is the use of transgenic Bacillus thuringiensis (Bt) technologies. Resistance to dual-gene cotton cultivars has recently been documented in bollworm, and results indicate that supplemental foliar applications may be needed to manage high populations. Research was conducted in 2021 and 2022 at Tiller (Drew County), Arkansas, to evaluate the efficacy of several Bt technologies. Results suggest that sprayed dual-gene cultivars had similar levels of damage to unsprayed three-gene cultivars. All three-gene treatments, sprayed non-Bt, and sprayed Bollgard II, had similar yields, which were greater than unsprayed non-Bt and unsprayed Bollgard II. These data suggest that dual-gene cultivars may need a supplemental foliar application for bollworm. [ABSTRACT FROM AUTHOR]

Tarnished plant bug (TPB) (Lygus lineolaris) is the number one insect pest of cotton in Arkansas, causing square loss, deformed flowers, and damaged bolls, ultimately reducing yield. Tarnished plant bug is difficult to control, and growers average 4-6 insecticide applications per year targeting TPB. Multiple insecticides are available for control of TPB, but resistance to some modes of action has been documented in this pest. Thryvon is a new cotton biotech trait that will provide season-long protection against TPB and thrips species, reducing the need for some insecticide applications. Cotton cultivars incorporating ThryvOn express the Cry51Aa Bt proteins that have been proven to provide some suppression of TPB. A study was conducted during the 2022 growing season at the University of Arkansas System Division of Agriculture's Lon Mann Cotton Research Station in Marianna to determine if the efficacy of TPB insecticides was different on ThryvOn and non-ThryvOn cotton. Insecticide treatments included bifenthrin (6.4 fl oz/ac), acephate (0.75 lb/ac), novaluron (6 fl oz/ac), sulfoxaflor (1.5 oz/ac), and thiamethoxam (2 oz/ac). Plots were sampled at 3, 7, and 11 days after the first application and 4, 7, and 11 days after the second application. A general trend was observed that insecticide efficacy was improved with all insecticides in ThryvOn cotton when compared to non-ThryvOn cotton. This same trend was observed for square retention and yield. [ABSTRACT FROM AUTHOR]

Transgenic Bt cotton has not eliminated the need for supplemental foliar insecticidal applications. Prior to the introduction of transgenic cotton expressing insecticidal proteins derived from Bt, foliar insecticides were used as the main control method of Helicoverpa zea. Due to high technology fees and documented cotton bollworm resistance to transgenic Bt technologies, supplemental foliar applications may be required to manage high populations of H. zea. Despite additional input costs, growers could achieve greater profits with an insecticide application when bollworm threshold is exceeded. Research was conducted in 2022 in Drew County, Arkansas, to evaluate several insecticides, including Prevathon, acephate, and bifenthrin, for efficacy and residual control of H. zea on multiple Bt cotton technologies. Results suggest that sprayed Bollgard II had similar levels of damage to all Bollgard III treatments. All Bollgard II treatments, sprayed Bollgard II, and non-Bt plots receiving a second insecticide application had similar yields, which were greater than unsprayed non-Bt and non-Bt sprayed with Prevathon or acephate plus bifenthrin. [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]

Rice stink bugs (RSB) are a major pest of rice after panicle emergence in Arkansas. Pyrethroids, particularly lambdacyhalothrin (lambda), have been the primary insecticide used to control RSB for the past 15 years. Recently, there have been increasing concerns of potential pyrethroid resistance. Lambda control failures have been documented in Arkansas in late-season RSB populations since 2019. Populations of RSB's were collected in May, June, July, and August throughout the state in 2021 and 2022. Lambda was applied to petri dishes at multiple rates to determine the efficacy of RSB. Fiftyfour collections were made throughout 2021 and 2022. Over the fifty-four populations that were sampled, percent mortality ranged from 66% to 68% between the 1x and 4x rates of lambda. Slightly higher mortality was observed in May as compared to the other months collections were made. These preliminary results indicate that pyrethroid insecticide resistance may become an increasing problem in Arkansas, and future management strategies need to be evaluated. [ABSTRACT FROM AUTHOR]

Rice stink bug (RSB) is a major pest of rice, feeding on developing grain, which can lead to yield and quality losses. Few insecticides are currently available to rice producers for rice stink bug management. Lambda-cyhalothrin (lambda) is the most common insecticide used to manage RSB due to its low cost. Over 50% of Arkansas rice acreage is treated with lambda for control of RSB annually. Other options, such as Tenchu (dinotefuran), are effective for control but not at a competitive price point. The dependency on lambda for RSB control, and control issues observed in Louisiana and Texas, raises concern for RSB resistance in Arkansas. New options for RSB need to be evaluated to determine effective alternatives to lambda. Foliar efficacy field trials were performed in 2021 and 2022 to compare insecticides for efficacy and residual control of rice stink bug. Sweep net samples were taken at 3, 7, 10, and 14 days after treatment (DAT) to monitor RSB efficacy. Excluding the pyrethroids, all other insecticides provided adequate control of RSB at 3 and 7 DAT. Only Tenchu and Endigo ZCX provided adequate control of RSB at 10 and 14 DAT. [ABSTRACT FROM AUTHOR]

Grape colaspis (GC) and rice water weevil (RWW) are the most common and destructive insect pests of early-developing rice in the Southern US. The larvae of both pests are the main contributors of injury, feeding on the plant roots and leading to yield losses. The most common method of control for both pests is the use of insecticide seed treatments (IST). Foliar insecticide applications are also a control tactic for RWW but are not effective for grape colaspis. In 2022, research was conducted at two locations to compare ISTs and IST combinations for management of these pests on both conventional and hybrid rice cultivars. Further, varying rates of Dermacor were evaluated to determine if the rate could be reduced and still achieve adequate control while reducing the overall cost. All insecticide treatments provided greater control of RWW compared to the untreated check. Other than the hybrid cultivar at the Stuttgart location, no differences were observed among Deramcor rates. A general trend was observed that the higher rates of Dermacor had lower RWW densities compared to lesser rates. Results from this research suggest that reduced rates of Dermacor provide similar control to full rates which could potentially lower the cost of the overall seed treatment package. [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]

Reflecting recent changes of the Arkansas rice industry and streamlining the delivery of new and improved rice varieties to Arkansas rice growers, the medium-grain rice breeding project has expanded its research areas and breeding populations to include conventional, Clearfield®, and Provisia® medium-grain and long-grain rice as well as hybrid rice. The newest elite breeding lines/varieties from collaborating programs, as well as lines with diverse genetic origins, will be actively collected, evaluated, and incorporated into current crossing blocks for programmed hybridization. To improve the efficiency and effectiveness of the program, maximum mechanized-operation, multiple generations grown in the winter nursery, and new technologies such as genomic selection are vigorously pursued. [ABSTRACT FROM AUTHOR]

The susceptibility of sawtoothed grain beetle, Oryzaephilus surinamensis, to pirimiphos-methyl, spinosad, deltamethrin, silicone dioxide and s-methoprene was evaluated utilizing 55-gallon barrels of stored corn. Spinosad provided protection to grain for 298 days. Pirimiphos-methyl protected grain for up to 329 days. Bioassays were conducted measuring the mortality of the red flour beetle, Tribolium castaneum, and the rice weevil, Sitophilus oryzae, to pirimiphos-methyl and deltamethrin in the laboratory. The LC50 for deltamethrin was 9.11 for S. oryzae and 0.026 for T. castaneum. The LC50 values for pirimiphos-methyl were 0.74 for S. oryzae and 13.44 for T. castaneum. [ABSTRACT FROM AUTHOR]

Tarnished plant bug (TPB) is the most important pest in mid-South cotton production, causing square loss, deformed flowers, and damaged bolls, ultimately reducing yield. Tarnished plant bug is difficult to control, with growers averaging 4-6 insecticide applications per year. A field study was conducted at two locations across two years to evaluate ThryvOn, a new transgenic trait in cotton producing the Bt protein Cry51Aa, for TPB control. The trial consisted of ThryvOn and non-ThryvOn cotton that was either left untreated or sprayed at 1x, 2x, or 3x the currently recommended University of Arkansas System Division of Agriculture's Cooperative Extension Service threshold. When treated at standard threshold, ThryvOn required 2.5 applications for TPB compared to 4.0 in non-Thryvon over both locations and years. Yields of the ThryvOon were not affected by the application treatments. Results from this study indicate that Thryvon may be a valuable tool in TPB management. [ABSTRACT FROM AUTHOR]

Armyworms are commonly found in rice fields in the mid-southern U.S. and have the potential to cause severe defoliation to the rice crop. Infestations can occur at all growth stages of rice. A defoliation threshold was developed in pure-line rice recently, hybrid cultivars need to be evaluated. Studies were conducted in 2022 where both pure-line and hybrid rice were mechanically defoliated at 100% with a weed eater at the two-three leaf, early tiller, late tiller, and green ring growth stages across three planting dates. Less yield loss was observed in the Apr planting in the hybrid cultivar compared to the pure-line regardless of growth stage. Similar yield losses were observed at the two-three leaf and early tiller growth stages between hybrid cultivars and pure-line cultivars at the May and Jun plantings. The hybrid cultivar had less yield loss compared to the pure-line cultivar at the late tiller and green ring growth stages for May and June plantings. This data suggest that thresholds could potentially be increased in hybrids compared to conventional cultivars. [ABSTRACT FROM AUTHOR]

The 2 most damaging lepidopterous soybean pests in Arkansas are corn earworm (Helicoverpa zea) and soybean looper (Chrysodeixis includens). On average, corn earworm is soybean's most damaging insect pest [Glycine max (L.) Merr.] in Arkansas, soybean looper is the third most damaging. The objective of this study was to combine data from the past 5 years of corn earworm and soybean looper insecticide efficacy trials and examine commonly recommended products for efficacy and residual control of these pests. Data indicate chlorantraniliprole and chlorantraniliprole + pyrethroid provided the greatest control of corn earworm while Denim® 8 oz/ac, Intrepid Edge® 5 oz/ac, and chlorantraniliprole provided the greatest control of soybean looper. [ABSTRACT FROM AUTHOR]

Trials were established in 2020-2021 to determine the impact of variety on grain disease. When analyzed across maturity groups, trends emerged in the occurrence of purple seed stain (Cercospora spp.) and Phomopsis seed decay (Phomopsis longicolla) that indicated the environment after maturity and until harvest influenced overall seed quality. Additionally, stink bug (Pentatomidae spp.) feeding did not appear to result in a greater occurrence of either of these diseases in either year. [ABSTRACT FROM AUTHOR]

Transgenic Bacillus thuringiensis (Bt) technologies are one of the widely used methods of controlling cotton bollworm (Helicoverpa zea). Due to high technology fees and documented cotton bollworm resistance to transgenic Bt technologies, supplemental foliar applications may be required to manage high populations of bollworm. Despite additional input costs, growers could achieve greater profits with an insecticide application when bollworm threshold is exceeded. Research was conducted in 2021 in Drew County, Arkansas, to evaluate several insecticides, including Prevathon, acephate, and bifenthrin, for efficacy and residual control of cotton bollworm on multiple Bt cotton technologies. Results suggest that sprayed Bollgard II had similar levels of damage to all Bollgard 3 treatments. All Bollgard 3 treatments, sprayed Bollgard II, and non-Bt plots receiving a second insecticide application had similar yields, which were greater than unsprayed non-Bt and non-Bt sprayed with Prevathon or Acephate plus Bifenthrin. [ABSTRACT FROM AUTHOR]

A widely used method of controlling cotton bollworm (Helicoverpa zea) in cotton is the use of transgenic Bacillus thuringiensis (Bt) technologies. Resistance has recently been documented in cotton bollworm to dual gene cotton cultivars, and results indicate that dual gene cultivars may require supplemental foliar applications to manage high populations. There is some evidence that, while more efficacious against bollworm, three-gene cotton cultivars yield less than dual-gene cultivars. Despite this yield gap, growers could have greater profits using three-gene cultivars due to lower input and production cost. Research was conducted in 2021 in Drew County, Arkansas, to evaluate the efficacy of several Bt technologies and the economic value of Bollgard II and Bollgard 3 technologies. Results suggest sprayed dual-gene cultivars had similar levels of damage to unsprayed three-gene cultivars. All three-gene treatments, sprayed non-Bt and sprayed Bollgard II, had similar yields, which were greater than unsprayed non-Bt and unsprayed Bollgard II. [ABSTRACT FROM AUTHOR]

Tarnished plant bug (TPB) is the most important pest in mid-South cotton production, causing square loss, deformed flowers, and damaged bolls, ultimately reducing yield. Tarnished plant bug is difficult to control, with growers averaging 4-6 insecticide applications per year. A field study was conducted in Marianna, Arkansas in 2021 to evaluate Thryvon, a new transgenic trait in cotton that produces the Bt protein Cry51Aa, for TPB control. The trial consisted of Thryvon and non-Thryvon cotton that were either left untreated or sprayed at 1x, 2x, or 3x the currently recommended University of Arkansas System Division of Agriculture threshold. Based on our standard threshold, Thryvon required 2 applications for TPB compared to 5 in non-Thryvon at Marianna. Yields in unsprayed Thryvon were no different than any of the sprayed Thryvon treatments. Results from this study indicate that Thryvon may be a valuable tool in TPB management. [ABSTRACT FROM AUTHOR]