Single Application Treatments Research Articles

Tracing the Transformation and Allocation of the Newly Applied-P in Calcareous Soil Using an Enriched Oxygen Isotope Labeling Technique.

Different phosphorus (P) fertilizations significantly impact the transformation of the applied-P in soils. However, knowledge about how different P fertilization regimes influence the allocation of the amended-P in soil remains incomplete. Herein, we carried out a pot experiment to explore the fate of applied-P in calcareous soil using an oxygen isotope labeling technique (18O-P18O43-). Treatments included check (CK), single, and repeated applications. The phosphorus mass balance result showed that more than 48.5% of the applied-P was held in labile and moderately labile fractions with the repeated treatment, while approximately 27.4% of the added-P was recovered in nonlabile forms in the single application treatment. The isotopic tracer (18O-P18O43-) result demonstrated that the δ18OP values of NaHCO3-P and NaOH-P in the repeated P application were significantly higher than those in the single P application. Ultimately, better agronomic performances of the crops and higher PUE were achieved in the repeated treatment. Our findings highlighted that repeated P fertilization can improve P availability by reducing P fixation. These results pronounced that the enriched oxygen isotope technique can be considered an effective approach for tracing applied-P in soils.

Efficacy of Genetic Resistance and Fungicide Application Against Fusarium Head Blight and Mycotoxins in Wheat Under Persistent Pre- and Postanthesis Moisture.

Field experiments were conducted to investigate the efficacy of fungicide treatments in combination with genetic resistance against Fusarium head blight (FHB) and its associated mycotoxins under persistently wet pre- and postanthesis conditions in plots inoculated with Fusarium graminearum-colonized corn spawn. Treatments consisted of a single application of prothioconazole + tebuconazole at early anthesis (PA), or at 3 (P3), 6 (P6), or 9 (P9) days after early anthesis, or PA followed by a single application of metconazole at 3 (PA+C3), 6 (PA+C6), or 9 (PA+C9) days after early anthesis. PA and P3 were the most efficacious of the single-application treatments in terms of mean percentage control of FHB index (IND), deoxynivalenol (DON), zearalenone (ZEA), and mean increase in grain yield and test weight (TW) relative to the nontreated susceptible check (S_CK). The double-application treatments (PA+C3, PA+C6, and PA+C9) were the most effective of all tested fungicide programs. However, relative to S_CK, the highest overall mean percentage reduction in IND, DON, and ZEA and increase in grain yield and TW were observed when the double-application fungicide programs were integrated with genetic resistance. The estimated net cash income (NCI) of the integrated management (IM) programs was consistently higher than the NCI of other tested programs across different grain prices and fungicide application costs. Thus, the benefits of the two-treatment IM programs under highly favorable conditions for FHB development were enough to offset the cost of two applications, making these programs profitable.

Manufacturability of a Tetraethyl Orthosilicate-Based Hydrogel for Use as a Single Application Otitis Externa Therapeutic.

Otitis externa, also known as outer ear infection, is a frequent affliction in both humans and animals. The most prevalent treatment for otitis externa is ear drops, but it is difficult to adhere properly to this treatment, causing poor patient compliance and the potential for complications. As a result, we have developed a tetraethyl orthosilicate-based hydrogel for use as single application treatment for otitis externa to increase ease of use and improve patient outcomes. Herein, we investigated the manufacturability of the hydrogel, focusing on several key aspects: formulation repeatability and reproducibility, material source and tolerances, release of a variety of model drugs, and impact of application-specific physiological factors, specifically local pH and enzymatic activity on drug release. Overall, our results indicate that these hydrogels are well suited for production and scalability, as they have a robust manufacturing process, have a wide tolerance for pH level, release a variety of model drugs, and are not impacted by outer ear canal-specific physiological factors.

Aplikasi Pestisida Nabati Maja - Gadung dan Metabolit Sekunder Beauveria Bassiana Bals. Untuk Mengendalikan Hama Thrips Sp. Pada Tanaman Cabai Rawit

Pest attacks on chili plants are the main limiting factor in cultivation activities. The research aims to determine the effect of single application of botanical pesticide maja-gadung (PMG), single application of secondary metabolite Beauveria bassiana BIO (BIO B10), combined application of PMG and BIO B10 on pest populations, predator populations and plant growth and production of chili. The reesearh used a factorial Completely Randomized Block Design (RAKL) with 3 replications, so there were 9 treatment combinations (0 ml/l PMG, 4 ml/l PMG, 8 ml/l BIO B10, 0 ml/l PMG, 2 ml/l BIO B10, 4 ml/l BIO B10, 4 ml PMG+2 ml/l BIO B10, 4 ml/ml PMG+4 ml BIO B10, 8 ml/l PMG+2ml/l BIO B10, 8 ml/l PMG+4 ml/l BIO B10). The variables observed were Thrips sp population, predator population, plant height, number of leaves, and fruit weight per plant. The results showed that the single application treatment of PMG with a concentration of 4 ml/l and 8 ml/l was able to suppress the population of Thrips sp. by 21.6% and 41.4% compared to the control. The single application treatment of BIO B10 with concentrations of 2 ml/l and 4 ml/l was able to suppress the population of Thrips sp. by 66.5% and 65.5% compared to the control. The best combination application is PMG and BIO B10with a concentration of 8 ml/l + 4 ml/l which is able to suppress the population of Thrips sp. by 76.9% compared to the control. The application treatment of PMG andBIO B10 did not affect plant height, number of leaves, and fruit weight per plant.

Efficacy of variable timing of Pythium oligandrum applications on red clover grown under field conditions

Biological control of root diseases of red clover (Trifolium pratense L.) could be effective but optimization of its application is needed to balance treatment efficacy with costs. Our objectives were to evaluate the effects of different Pythium oligandrum application treatments on root morphological development, plant root disease score and forage yield in a three-year field experiment. Red clover cv. Start was managed under a three-cut management in two harvest years with four treatments: (i) untreated control, (ii) multiple applications of P. oligandrum (intensive treatment), (iii) a single spring application, and (iv) a single autumn application. Plants from each plot were evaluated for root morphology traits and scored for root diseases in each autumn. Forage yield, compressed stand height and stem density were evaluated in each cut. All P. oligandrum treatments increased root dry matter and root potential index, but only the intensive treatment significantly improved forage yield (by 31%) in comparison with the control. This effect could be largely associated with plant growth stimulation resulting in increased stand height before cutting. Among single application treatments, autumn timing significantly reduced plant root disease score and showed higher stand height than spring application. One application later in the season seems likely to be effective for forage growth stimulation, but probably at least two applications are needed to produce maximum effect. Despite some drought stress during the first two years, this field study confirmed an effect of P. oligandrum on improved root development and a positive yield response, thus showing a high potential of this biological control treatment under field conditions.

Short-chain soluble polyphosphate fertilizers increased soil P availability and mobility by reducing P fixation in two contrasting calcareous soils.

Short-chain polyphosphate fertilizers have been increasingly applied in agriculture, but little is known about the chemical behaviors of polyphosphate in soils. Herein, a cylinder experiment was carried out to investigate the influences of different P types (i.e., mono-ammonium phosphate (MAP), phosphoric acid (PA) and ammonium polyphosphate (poly-P)) and their application methods (single vs split) on the mobility and availability of P in soil through a column millimeter-scale slice cutting method; meanwhile a soil microcosm experiment (560-day) was conducted to investigate the effects of different P types on phosphorus dynamic transformation. Polyphosphate addition significantly increased P mobility. The average distance of P downward movement (81.5 mm) in soil profile in the poly-P application treatment increased by 33.6% and 81.1%, respectively, compared to the MAP and PA treatments. Different P application methods also markedly influenced phosphorus mobility. For instance, the average distance of P vertical movement in the split P application treatment was 21.2% higher than in the single application treatment, indicating that split P addition significantly increased P downward movement. Moreover, polyphosphate application decreased soil P fixation by blocking the transformation of the applied-P from labile to recalcitrant forms (HCl-P and residual-P). Overall, our findings provide meaningful information to current phosphorus fertilization practice in increasing soil P mobility and bioavailability. We suggest that polyphosphate could be regarded as an alternative P source used in agriculture, and split polyphosphate application is recommended as an effective P fertilization strategy.

Abametapir for the Treatment of Head Lice: A Drug Review.

This article reviews the pharmacology, safety, efficacy, and clinical importance of abametapir 0.74% (Xeglyze) for the treatment of head lice. From 2020 to May 2021, a systematic review of the MEDLINE and EMBASE databases was conducted using the terms abametapir, Xeglyze, Ha44, and head lice. Bibliographies, Food and Drug Administration (FDA) drug package inserts, and ClinicalTrials.gov were searched for further information. All relevant full-text articles in English were considered for inclusion, with a final article date range of 1999 to 2020. Abametapir chelates heavy metal cations and inhibits metalloproteinases critical to louse ova development, hatching, and adult survival. In phase II, abametapir had direct ovicidal activity inhibiting 100% of treated louse eggs from hatching, compared with 64% in the vehicle-treated group. In two identical phase III clinical trials, subjects treated with a single 10-minute application of abametapir had greater treatment success compared with vehicle-treated subjects, with 81.1% success versus 50.9% in study 1 (P = 0.001) and 81.8% versus 47.2% in study 2 (P < 0.001). Abametapir was well tolerated, with only mild adverse effects. Abametapir is a newly FDA-approved, single-application treatment for head lice in patients aged 6 months and older. This review highlights the safety and efficacy of abametapir in the treatment of head lice. In the wake of increasing widespread resistance to first-line treatment options, abametapir offers a safe and effective new treatment option for head lice infestations.

Influence of application method and number of applications of nanolime on the effectiveness of the Doulting limestone treatments

Over the last two decades, nanolime has been recognized as a promising consolidation approach to consolidate historic calcareous substrates due to its compatibility, durability and fast carbonation. The effectiveness of nanolime products has been widely proven for superficial consolidation treatments, especially in historic wall-paintings. However, its consolidation mechanism in highly porous substrates, such as in the case of limestones or lime mortars, still needs to be fully understood. This paper aims to study the influence of application method and number of applications on the effectiveness of nanolime treatments, which has never been targeted until now. In this experimental work, the Ca(OH)2 nanoparticles were freshly synthetized by anion exchange resins and applied in historic Doulting limestone samples, extracted from a capital from the Cathedral of Wells (Somerset, UK). In order to study the influence of application method on the effectiveness of treatments, samples were treated by: (1) brush; (2) spray; and (3) capillary absorption. Additionally, to study the influence of the number of applications on the consolidation effectiveness, these three application methods were applied by: (1) 1 application; (2) 5 applications; (3) 10 applications. The consolidation effectiveness of the resulting nanolime treatments was studied by assessing changes in porosity, superficial and internal stone’s density, superficial cohesion, water absorption by capillarity and aesthetic properties. Results showed that repeated applications (i.e. 10 applications) of a low concentrated nanolime (i.e. 5 g/L) by spray and brush can increase the superficial cohesion, mechanical properties and density of the stone at the surface. Additionally, results suggest that the application method does not significantly affect the consolidation effectiveness of nanolime treatment, contrary to what was commonly believed. Results also show that a single application treatment of low concentrated nanolime (i.e. 5 g/L) does not significantly provide noticeable consolidation effectiveness regardless of the application method, also contrary to what was commonly believed. These results suggest that for a noticeable consolidation treatment with low concentrated nanolime the application must consist of several applications (> 10). This could have a high impact on the Built Heritage conservation community that commonly use nanolime in conservation activities.

Reapplication of bud break promoters in ‘Fuji Suprema’ apple trees

Abstract The aim of this work was to verify the effectiveness of the reapplication of bud break producers on flowering, sprouting and production of ‘Fuji Suprema’ apple trees. The experiment was carried out in an experimental orchard located in the municipality of Caçador, SC, during 2016/2017 to 2019/2020 seasons. Treatments were applied at stages B and C, and those with reapplication, from 7 to 14 days after the first application. Phenology, axillary and terminal bud break, frui set, production per plant and average fruit mass were evaluated. Phenology was advanced in relation to control with the application of bud break promoters. However, treatments applied at stage B provided greater advance in relation to applications at stage C. In axillary and terminal bud break, all treatments were superior to control. In some seasons, the sequential application of bud break promoters increased bud sprouting compared to single application treatment. There is no reduction fruit set in treatments with sequential application in relation to single application. In plant production, sequential applications did not differ from single application. The average fruit mass was not altered by the sequential application of bud break promoters.

Changes to tetracyclines and tetracycline resistance genes in arable soils after single and multiple applications of manure containing tetracyclines.

The influence of manure containing tetracyclines (TCs) on the prevalence of antibiotic resistance genes in soils remains poorly understood. Here, three different TCs (oxytetracycline (OTC), tetracycline (TC), and chlortetracycline (CTC)) were mixed respectively with unpolluted manure to fertilize arable soil. The soil received either a single application of 0μgkg-1, 300μgkg-1 (TC and CTC), or 700μgkg-1 (OTC) or multiple applications every 14days for 140days. Four tetracycline resistance genes (TRGs), including tet(A), tet(L), tet(M), and tet(Q), were monitored. Although the abundances of the four TRGs in the single application treatment initially increased rapidly, they decreased over time and were significantly lower than those of the repeated treatments after day 112. All additions of TCs stopped on day 140, but we continued to assess the long-term accumulation of TRGs. Most of the TRGs were detected even after the TC-containing manures had not been applied for more than 15months. The abundance of the TRGs after ceasing fertilization with the TC-containing manures was higher in the repeated application treatments than in the single application treatments. Therefore, more attention should be paid to repeated applications of antibiotic-containing manure to arable soils.

RESPONSE OF POTATO TO POTASSIUM FERTILIZER SOURCES AND APPLICATION METHODS IN ANDISOLS OF WEST JAVA

An experiment to determine the response of potato to potassium (K) fertilizer sources and application methods in Andisols of West Java was conducted at a farmer’s field in the highland area of Pangalengan (1400 m asl.), West Java from August to November 2004. The treatments consisted of two K fertilizer sources (potassium chloride-KCl and potassium sulphate-K2SO4), two K rates (150 and 250 kg K2O ha-1), and three application methods (single, split, and split combined with foliar application), were arranged in a randomized complete block design with four replications. In the single application treatment, K was applied at planting, while in the split application treatment the K was applied half rate at planting and the rest at 6 weeks after planting (WAP). In the split combined with foliar application treatment, the K fertilizer was applied half rate at planting, a quarter rate at 6 WAP and another quarter rate by foliar spraying at 7, 8 and 9 WAP. The results showed that plant height was not significantly affected by the treatment (P &amp;gt;0.05). However, the sources and application methods of K fertilizer affected canopy cover, crop cover weeks (CCW), tuber dry weight (DW), and total plant DW at 10 WAP. Potatoes supplied with K2SO4 either in split or split combined with foliar application had significantly higher percent canopy cover, CCW, tuber DW, and total plant DW than those supplied with K fertilizer in single application. Potatoes supplied with K2SO4 had a higher tuber yield compared to those fertilized with KCl, especially under split or split combined with foliar application. To attain the same level of tuber yield as in the split combined with foliar application method, the rate of K2SO4 should be increased from 150 to 250 kg K2O ha-1 when using single application. It is therefore suggested that K2SO4 for potatoes should be used in split application combined with foliar application.

RESPONSE OF POTATO TO POTASSIUM FERTILIZER SOURCES AND APPLICATION METHODS IN ANDISOLS OF WEST JAVA

An experiment to determine the response of potato to potassium (K) fertilizer sources and application methods in Andisols of West Java was conducted at a farmer’s field in the highland area of Pangalengan (1400 m asl.), West Java from August to November 2004. The treatments consisted of two K fertilizer sources (potassium chloride-KCl and potassium sulphate-K2SO4), two K rates (150 and 250 kg K2O ha-1), and three application methods (single, split, and split combined with foliar application), were arranged in a randomized complete block design with four replications. In the single application treatment, K was applied at planting, while in the split application treatment the K was applied half rate at planting and the rest at 6 weeks after planting (WAP). In the split combined with foliar application treatment, the K fertilizer was applied half rate at planting, a quarter rate at 6 WAP and another quarter rate by foliar spraying at 7, 8 and 9 WAP. The results showed that plant height was not significantly affected by the treatment (P &amp;gt;0.05). However, the sources and application methods of K fertilizer affected canopy cover, crop cover weeks (CCW), tuber dry weight (DW), and total plant DW at 10 WAP. Potatoes supplied with K2SO4 either in split or split combined with foliar application had significantly higher percent canopy cover, CCW, tuber DW, and total plant DW than those supplied with K fertilizer in single application. Potatoes supplied with K2SO4 had a higher tuber yield compared to those fertilized with KCl, especially under split or split combined with foliar application. To attain the same level of tuber yield as in the split combined with foliar application method, the rate of K2SO4 should be increased from 150 to 250 kg K2O ha-1 when using single application. It is therefore suggested that K2SO4 for potatoes should be used in split application combined with foliar application.

Effects of different concentrations and application frequencies of oxytetracycline on soil enzyme activities and microbial community diversity

Antibiotics in soil can interfere with the structure and function of the soil microbial community and represent a potential genetic pollution risk. The effects of different concentrations and application frequencies of oxytetracycline (OTC) to an agricultural soil on the activities of soil microorganisms and enzymes were investigated during incubation of 120 days. Single once-only high application treatments (1, 3.6, 10, and 30 mg OTC kg−1 soil) and one daily low application treatment (0.03 mg OTC kg−1 soil every day) were compared to simulate OTC application to the soil in sewage sludges or manures or from waste water irrigation. In the single addition treatments, microbial biomass carbon (Cmic) in the soil increased 2.17–3.29 times and 1.37–2.08 times after 7 and 42 d of incubation, respectively, but nitrification potential increased sharply to 3.01–10.9 times after 28 d and dehydrogenase activity was also significantly stimulated after 14 d compared to the zero OTC control and decreased sharply by 120 d. The daily OTC addition treatments promoted Cmic (up to 2.64 times) and increased the McIntosh index (p < 0.05) between 60 and 90 days as calculated using Biolog data and compared to the zero OTC control. A single high rate of OTC addition showed a generally more pronounced negative effect on soil microbial community metabolism (but not on functional diversity indices of the soil microbial community) than repeated small rates of addition because with equal amounts of added OTC (single 3.6 mg kg−1 and daily 0.03 mg kg−1 OTC) Cmic, nitrification potential and neutral phosphatase activity at 120 d were significantly lower in the single application treatments.

Ex vivo effectiveness of French over-the-counter products against head lice (Pediculus humanus capitis De Geer, 1778).

Head lice infestation is still a public health problem worldwide, with an intracountry and intercountry prevalence variation of 0.7 to 59%. There is a large variety of over-the-counter anti-louse products, but their efficacy is not always well assessed. Our objective was to test the pediculicidal and ovicidal efficacy of 21 over-the-counter head louse products, available in France during the period of 2008 to 2012. We tested children living in Tours City in central France and visiting preschools, primary schools, kindergarten, camps, and child care facilities, as well as children in their family houses, and were examined for the presence of lice. The products were collected from randomly selected pharmacies by covert investigators and then tested in the laboratory on an ex vivo sample of head lice and their eggs, collected from the hair of infested children. Living lice and unharmed eggs were collected from the scalps of 3-12 years old. The laboratory conditions for ex vivo testing mimicked the manufacturers' instructions for exposure time and application method. In 21 runs, 3919 living lice and 4321 undamaged living eggs were collected from the scalp of over 400 children. The 21 products were classified in three groups: 6 products in a group of potentially 100% pediculicidal activity and potentially 100% ovicidal activity, 8 products in a group of potentially 100% pediculicidal activity but insufficient ovicidal activity (including 2 products with claims of single application treatment), and 7 products in a group of insufficient pediculicidal activity and ovicidal activity. The pharmaceutical market for head lice products in France is swamped with poorly tested and ineffective products. Rigorous efficacy testing preregistration and periodic screening and testing of effectiveness in the post-registration period should be endorsed by the health authorities.

Nicosulfuron Use with Foramsulfuron and Sulfentrazone for Late Summer Goosegrass (Eleusine indica) Control in Bermudagrass and Seashore Paspalum

Late summer goosegrass control is difficult in turfgrass as POST herbicide efficacy is reduced on mature plants. Field experiments were conducted to evaluate single and sequential nicosulfuron applications tank-mixed with foramsulfuron or sulfentrazone for late summer goosegrass control and safety to bermudagrass and seashore paspalum. All single-treatment applications controlled goosegrass &lt; 62%, whereas sequential sulfentrazone, nicosulfuron, and nicosulfuron + sulfentrazone applications controlled goosegrass 52, 73, and 84%, respectively. Sequential foramsulfuron applications controlled goosegrass &lt; 55% but nicosulfuron tank-mixtures did not improve control. Bermudagrass was injured &lt; 20% by 1 and 3 wk after all single and sequential treatments. Sequential treatments of nicosulfuron alone or tank-mixed with sulfentrazone caused unacceptable seashore paspalum injury (&gt; 20%) 1 and 3 wk after the second application, whereas foramsulfuron or sulfentrazone alone applied sequentially caused &lt; 17% injury. Seashore paspalum seedhead control at 9 wk after intial treatment was poor (&lt; 70%) from all single-application treatments and sequential sulfentrazone applications, but control was good (80 to 89%) to excellent (&gt; 90%) from all other treatments. Overall, sequential treatments of nicosulfuron alone or tank-mixed with sulfentrazone appear to have potential for POST control of mature goosegrass in bermudagrass, but seashore paspalum injury was unacceptable.

Ecological impacts of time-variable exposure regimes to the fungicide azoxystrobin on freshwater communities in outdoor microcosms

This paper evaluates the effects of different time-varying exposure patterns of the strobilurin fungicide azoxystrobin on freshwater microsocosm communities. These exposure patterns included two treatments with a similar peak but different time-weighted average (TWA) concentrations, and two treatments with similar TWA but different peak concentrations. The experiment was carried out in outdoor microcosms under four different exposure regimes; (1) a continuous application treatment of 10 μg/L (CAT10) for 42 days (2), a continuous application treatment of 33 μg/L (CAT33) for 42 days (3), a single application treatment of 33 μg/L (SAT33) and (4) a four application treatment of 16 μg/L (FAT16), with a time interval of 10 days. Mean measured 42-d TWA concentrations in the different treatments were 9.4 μg/L (CAT10), 32.8 μg/L (CAT33), 14.9 μg/L (SAT33) and 14.7 μg/L (FAT16). Multivariate analyses demonstrated significant changes in zooplankton community structure in all but the CAT10 treated microcosms relative to that of controls. The largest adverse effects were reported for zooplankton taxa belonging to Copepoda and Cladocera. By the end of the experimental period (day 42 after treatment), community effects were of similar magnitude for the pulsed treatment regimes, although the magnitude of the initial effect was larger in the SAT33 treatment. This indicates that for long-term effects the TWA is more important for most zooplankton species in the test system than the peak concentration. Azoxystrobin only slightly affected some species of the macroinvertebrate, phytoplankton and macrophyte assemblages. The overall no observed ecologically adverse effect concentrations (NOEAEC) in this study was 10 µg/L.

Height Control in Three Pepper Types Treated with Drench-applied Abscisic Acid

Vegetable transplants can have excessive internode elongation before field establishment, producing challenges for the growers using mechanical transplanters to establish their crops. Thus, controlling the height of vegetable transplants before planting could be an advantage for commercial vegetable growers. A greenhouse experiment was conducted in 2008 (Year 1–2008) and 2009 (Year 2–2009) to determine the efficacy of exogenous drench-applied abscisic acid (ABA) applications for height control of transplanted pepper. Three types of pepper (Capsicum annuum L.) were investigated: bell pepper ‘Aristotle’, Jalapeño ‘Grande’, and banana pepper ‘Pageant’. In this greenhouse study, 10 ABA treatments, based on application frequency and timing, and an untreated control were arranged in a randomized complete block design with six (Year 1–2008) or five (Year 2–2009) replications and were evaluated over an 8-week period each year. Treatments included: single application at Week 1 (cotyledon stage), Week 2, Week 3, and Week 4; double applications were made at Weeks 1 + 2, Weeks 2 + 3, and Weeks 3 + 4; and multiple applications of ABA at Weeks 1 + 2 + 3, Weeks 2 + 3 + 4, and Weeks 1 + 2 + 3 + 4. All ABA applications were delivered as a drench applied directly to the planting container at a rate of 250 mg·L−1 ABA. Early, single-dose applications (Week 1) were more effective at controlling height than a single dose applied later; a Week 1 application measured during week 5 was 4.1 cm versus a Week 4 application measured at Week 5, which was 5.7 cm. Multiple ABA applications initiated early (at the cotyledon stage) of ‘Aristotle’ bell peppers were effective in controlling transplant height compared with any single ABA application; measured at Week 5, an application at Week 1 + 2 was 3.1 cm compared with the single application treatments from that same measurement date, which ranged from 4.1 to 5.7 cm. Differences among the response of pepper types to ABA application were observed. ‘Aristotle’ had significant treatment effects even 6 weeks after treatment. ‘Pageant’ (banana pepper) exhibited an intermediate response with effects lasting only 2 weeks. No significant height reductions resulting from ABA treatment were observed for ‘Grande’ (Jalapeño pepper). Multiple ABA dose applications initiated at the cotyledon plant growth stage can be used to effectively control transplant height of ‘Aristotle’ bell pepper seedlings.

Yield Response of Corn to Single and Combined Application of Cattle Manure and Urea

A 2-year field experiment was conducted to evaluate the single- and combined-application effects of cattle manure and urea on corn (Zea mays L.) production. A randomized complete block design was conducted with five nitrogen (N) rates (36, 72, 108, 144, and 180 kg N ha−1) as urea, cattle manure, or both. The stover yield and aboveground biomass increased with urea application up to 144 kg N ha−1 but remained unchanged at greater N rates. At all N rates, combined application of manure and urea resulted in greater grain yields than single applications. Crop response to applied N was greater in the combined N application system than in the single-application treatments. The greatest grain yield was found in plots that had received a combination of 18 ton manure ha−1 plus 160 kg urea ha−1. Manure application along with urea enhanced crop yield response to urea and reduced its application rate.

Effects of time‐variable exposure regimes of the insecticide chlorpyrifos on freshwater invertebrate communities in microcosms

The present study compared the effects of different time-variable exposure regimes having the same time-weighted average (TWA) concentration of the organophosphate insecticide chlorpyrifos on freshwater invertebrate communities to enable extrapolation of effects across exposure regimes. The experiment was performed in outdoor microcosms by introducing three different regimes: a single application of 0.9 µg active ingredients (a.i.)/L; three applications of 0.3 µg a.i./L, with a time interval of 7 d; and continuous exposure to 0.1 µg a.i./L for 21 d. Measurements showed that the TWA(21d) concentration in the continuous-exposure treatment (0.098 µg/L) was slightly lower than in the three-application (0.116 µg/L) and single-application (0.126 µg/L) treatments. The application of chlorpyrifos resulted in decreased abundances in the arthropod community, with the largest adverse effects reported for the mayfly Cloeon dipterum and cladocerans Daphnia gr. longispina and Alona sp., while smaller effects were observed for other insects, copepods, and amphipods. At the population level, however, the mayfly C. dipterum only responded to the single-application treatment, which could be explained by the toxicokinetics of chlorpyrifos in this species. At the end of the experimental period the invertebrate community showed approximately the same effect magnitude for all treatment regimes. These results suggest that for this combination of concentrations and duration of the TWA, the TWA concentration is more important for most species than the peak concentration for the assessment of long-term risks of chlorpyrifos.

Selective Nimblewill (Muhlenbergia schreberi) Control in Cool-Season Turfgrass

Isoxaflutole and mesotrione have been used to control creeping bentgrass in cool season turf, these experiments evaluate these two products for selective nimblewill control. Three experiments were conducted in Virginia and Tennessee to evaluate selective control options for nimblewill in cool-season turfgrass. Single applications of isoxaflutole control nimblewill more effectively than single applications of mesotrione. Nimblewill control 8 wk after initial treatment (WAIT) increased as mesotrione rates increased from 28 to 280 g ai/ha, and isoxaflutole rates increased from 28 to 168 g/ha. Isoxaflutole at 84 and 168 g/ha were the only single application treatments that controlled nimblewill greater than 80% 8 WAIT. However, sequential applications of isoxaflutole and mesotrione at 28 g/ha, 10 d apart controlled nimblewill 94 and 80%, respectively 8 WAIT. Triclopyr and fenoxaprop-p did not effectively control nimblewill and caused unacceptable turfgrass injury. Long-term control was not evaluated in these studies. However, it was concluded that isoxaflutole and mesotrione at appropriate rates and applied in sequence selectively control nimblewill without harming desirable turf.