Initial Treatment Application Research Articles

Comparison of Acetic Acid to Glyphosate for Weed Suppression in the Garden

Interest in organic vegetable gardening has increased in recent years. Organic growers are searching for alternatives to glyphosate for weed suppression. This study was conducted twice. Each data collection period lasted 132 days during the growing seasons of 2016 and 2017 in Richmond, KY. Treatments included application of glyphosate, vinegar [5% acetic acid (AA)], 20% horticulture grade vinegar (20% AA), 30% horticulture grade vinegar (30% AA), and a negative control. Treatments were applied in a factorial arrangement with two application periods (fall and spring or spring only). The percentage of weed cover within plots was evaluated visually with a 0–10 rating scale (0 = 0% weeds or 100% of the plot is dead; 5 = 50% weed growth; 10 = 100% of the plot is alive with weeds). All plots began the study with a rating of 10. After the initial treatment applications, visual ratings of the 5%, 20%, and 30% AA declined to a rating of 0 within 48 hours, whereas the glyphosate required 7 days (P = 0.05). Treatments were reapplied to part of the plots (subplots) in the spring when ≈50% of the plot had regrown with weeds. Glyphosate required 71 to 80.8 days to reach 50% regrowth and required only one retreatment. The 20% and 30% AA applications required three (2016) and four (2017) retreatments. Glyphosate has proven to be more effective at weed control in vegetable gardens when compared with vinegar, although 20% AA and 30% AA are viable alternatives.

Effects of transdermal flunixin meglumine on experimentally induced lameness in adult dairy cattle

Lameness is a common animal health condition with significant production and welfare implications. The transdermal formulation of flunixin meglumine is the only approved drug for pain control in cattle in the United States. Thirty adult dairy cows were enrolled in a study to determine the effect of transdermal flunixin on cattle with induced lameness. Cows were allocated to 1 of 3 treatment groups, with 10 cows per group: lameness and flunixin (L+F), lameness and placebo (L+P), or sham induction and placebo (S+P). An arthritis-synovitis was induced in the distal interphalangeal joint of the left hind lateral digit, using 20 mg of amphotericin B, 6 h before the application of treatment. Cows enrolled into the sham induction group had 4 mL of isotonic saline injected into the joint. Cows were dosed with transdermal flunixin at 3.33 mg/kg (1 mL/15 kg), or a placebo at 1 mL/15 kg, every 24 h for 3 d. The first treatment of flunixin or placebo was considered the start of the study, identified as time 0 h. Data were collected from all cows for 120 h following the initial treatment application. Outcome measures included plasma cortisol; substance P; visual lameness assessment; mechanical nociception threshold (MNT), presented as difference between left and right feet; infrared thermography (IRT), presented as difference between left and right feet; and gait analysis using a pressure mat. Cortisol concentrations were lower for the L+F group starting at 1.5 h after drug administration. Substance P levels showed no evidence for treatment differences among groups. Differences between the left hind MNT and right hind MNT were detected, with S+P having the lowest difference at -0.04 kilograms-force (kgf; 95% CI: -1.86 to 1.78 kgf), and L+P having the highest at -2.96 kgf (95% CI: 1.55 to 4.36 kgf). The L+F group was intermediate at -2.08 kgf (95% CI: 0.89 to 3.27 kgf). Similarly, when the difference between the maximum temperatures of the coronary band were examined via IRT, the L+P group had the highest difference at 1.64°C (95% CI: 1.02 to 2.26°C), with the L+F and S+P groups measuring 0.57°C (95% CI: 0.06 to 1.08°C) and 0.53°C (95% CI: -0.2 to 1.25°C) respectively. We found no evidence for differences among treatment groups when analyzing force, contact pressure, step impulse, or stride length. Based on differences in MNT, IRT, and cortisol, transdermal flunixin is an effective analgesic agent for induced lameness. Multiple doses of transdermal flunixin may be required to be clinically effective, based on MNT and IRT data. Further investigation of transdermal flunixin and its analgesic effects is warranted in naturally occurring lameness.

Plant defense elicitors: plant fitness versus wheat stem sawfly.

The wheat stem sawfly (WSS), Cephus cinctus Norton, is an important wheat pest in the Northern Great Plains of the USA. No single control measure effectively suppresses WSS damage. This study provides information on the effects on the WSS adult settling preference behavior on wheat plants under laboratory conditions from treatment with both synthetic plant defense elicitors (Actigard® and cis-jasmone) and a botanical insecticide (Azadirachtin®). In addition, field experiments were performed to determine whether these chemicals impact the WSS fitness (larval mortality and larval body weight), winter wheat plant fitness (infestation, stem lodging, yield, and quality), adult population of WSS and Bracon spp., and larval parasitism levels. Our lab results showed that there were no significant differences in adult settling behavior on plants exposed separately to each chemical and control. In contrast, when adults were exposed simultaneously to treated and untreated plants, there was a significant reduction in the percentage of adults settling on Actigard® and Azadirachtin® treated plants compared to plants sprayed with water in the same cage. However, in field situations, regardless of application timing and field location, none of the chemicals significantly reduced adult population or stems damage. The exception was two times applications of Actigard® had significantly lower WSS infested stem damage levels at 30 days after initial treatment applications at Knees and 50 days at Choteau locations compared to control, but without effect at the Conrad location. The field study indicated that two times applications of Actigard® significantly increased diapausing larval mortality percentages and lowered stem lodging levels compared to untreated controls at Knees and Choteau locations, while no effects at Conrad location. Larval body weight was significantly lower in plots treated with Actigard® at Knees and Conrad, but no effects at Choteau. No significant differences were found in wheat yield and quality in plots treated with chemicals and controls at any location. Bracon spp. adult population and parasitism levels were not negatively affected by the use of chemicals. In conclusion, this study offers insights on what treatments should be emphasized in more detail despite variable findings.

Soil carbon and nitrogen dynamics in the first year following herbicide and scalping in a revegetation trial in south-east Queensland, Australia

During revegetation, the maintenance of soil carbon (C) pools and nitrogen (N) availability is considered essential for soil fertility and this study aimed to evaluate contrasting methods of site preparation (herbicide and scalping) with respect to the effects on soil organic matter (SOM) during the critical early establishment phase. Soil total C (TC), total N (TN), hot-water extractable organic C (HWEOC), hot-water extractable total N (HWETN), microbial biomass C and N (MBC and MBN), total inorganic N (TIN) and potentially mineralizable N (PMN) were measured over 53 weeks. MBC and MBN were the only variables affected by herbicide application. Scalping caused an immediate reduction in all variables, and the values remained low without any sign of recovery for the period of the study. The impact of scalping on HWETN and TIN lasted 22 weeks and stabilised afterwards. MBC and MBN were affected by both herbicide and scalping after initial treatment application and remained lower than control during the period of the study but did not decrease over time. While scalping had an inevitable impact on all soil properties that were measured, that impact did not worsen over time, and actually improved plant growth (unpublished data) while reducing site establishment costs. Therefore, it provides a useful alternative for weed control in revegetation projects where it is applied only once at site establishment and where SOM would be expected to recover as canopy closure is obtained and nutrient cycling through litterfall commences.

RESPONSE OF RAPID DECLINE AFFECTED COCONUT (COCOS NUCIFERA L.) PALMS TO MICRO-NUTRIENTS AND COMMON SALT

Coconut Rapid Decline (CRD) is a serious disorder of coconut palms(Cocos nucifera L.) in Sri Lanka. A substantial loss of crop is well evidentdue to this disorder. This study aims to determine the effect of micronutrientsand common salt on the performance of CRD-affected palms.Fifteen-years-old, mild, moderate and severe CRD-affected palms, inMakandura Research Station (MRS) of Coconut Research Institute wereused for this study. Affected palms were treated with the micro-nutrients(100 ml of 0.35 % CuS04.5H2 0 and 0.72 % ZnS04.7H2 0 solution/palm, rootfeeding at bi-monthly intervals) or common salt (NaCI, 1 kg/palm/year,surface application in the manure circle). Untreated CRD-affected palmswere used as the control. Leaf nutrient levels before, one and two yearsafter treatment application were analyzed. Vegetative, reproductive andphysiological parameters were measured during two years, after treatmentapplication.Pre-treatment analysis of leaves revealed that Nitrogen (N) and Phosphorus(P) contents were within the sufficiency range and Potassium (K) contentwas above the sufficiency range in CRD-affected palms. Magnesium (Mg),Calcium (Ca), Sodium (Na), Copper (Cu) and Zinc (Zn) contents of thosepalms were below the sufficiency range. The macro and micro-nutrientcontents (except Mg) of apparently healthy palms, adjacent to CRD-affectedpalms were within the sufficiency range for coconut. Therefore, it issuggested that the CRD-affected palms suffer from deficiency of Ca, Na, Cuand Zn. There was a significant difference in Iron (Fe) content among threeseverity stages of CRD-affected palms before initial treatment application,Fe concentration increased with increasing severity.Phosphorus and Ca contents significantly increased in micro nutrient andcommon salt treated palms after one year, compared to before treatmentapplication and control. However, there was no significant increase in leafCu, Zn and Na levels, even after two years of the treatment application. Thepercentage of drooping fronds, size of the spadix, number of female flowers,number and size of nuts and circumference of the trunk were not improvedin treated palms one year after treatment. Two years after the treatment, number of total fronds and functional green fronds in the canopy of affectedpalms were increased by common salt application. The stomatal diffusiveresistance of these palms was also reduced after two years showing animprovement in palm water status. The experiment is in progress to.observe the recovery of symptoms.

Analysis of 4-year Dutch reimbursement application data of biological therapies for psoriatic arthritis

To get the approval for reimbursement of biological therapies for PsA, patients need to fulfil specific criteria in many countries. The aim of this study was to evaluate the 4-year Dutch reimbursement application data, including the diagnostic, disease activity and response criteria that were applied for treatment of PsA with biologics. All initial and follow-up applications for approval of treatment with biologics were included for investigation. Data were analysed descriptively with regard to application characteristics, patient characteristics and response to therapy. In the period studied, 3723 application forms of 1991 patients were received. This concerned 2118 initial treatment applications and 1605 follow-up applications. Of all initial treatment applications, 2003 (94.6%) were approved. The major part of all applications concerned requests for etanercept (59.1%), followed by adalimumab (38.2%). Patients were suffering from polyarthritis in most cases (63.1%). MTX was used by nearly all patients, but only 55.8% had used the required dosage of 25 mg/week. Approximately 79.4% of all patients met the response criteria after 3 months of treatment. The mean number of affected joints declined from 7.7 at first application to 1.4 at follow-up. The initial visual analogue scale (VAS) score indicated by patients decreased from 71.2 to 24.1 at follow-up. The VAS score indicated by physicians decreased from 66.0 to 18.4. Biologics are expensive, but highly effective in the treatment of PsA. Careful compilation of treatment and reimbursement criteria is important for patients as well as for physicians and health insurance companies.

Evaluating Solarization and Cultivated Fallow for Johnsongrass (Sorghum halepense) Control and Nitrogen Cycling on an Organic Farm

ABSTRACT A two-year field study evaluating efficacy of two weed control techniques on the noxious weed johnsongrass (Sorghum halepense L. Pers.) was conducted in Lexington KY. The weed control treatments were soil solarization, accomplished by covering the soil with clear plastic for 8 weeks, and cultivated bare fallow. Both treatments, along with a control treatment (mowing), were applied during the summers of 2003 and 2004 to a field heavily infested with johnsongrass (40–50% coverage). Effects of solarization on soil microbial activity and nitrogen (N) cycling were also evaluated. In both years, half of each treatment plot was lightly tilled 8 months after initial treatment application, and johnsongrass populations were characterized 2 months later. At the end of the experiment, the solarized-untilled treatment had lower johnsongrass populations than the cultivated-tilled and control treatments. Shallow tillage resulted in significantly more johnsongrass in the cultivated treatment in 2003, and in both cultivated and solarized treatments in 2004, compared with their untilled counterparts. At the conclusion of the experiment the johnsongrass populations were considerably reduced in both treatments compared with the original infestation. Solarization resulted in significant increases of both NH4-N and NO3-N in the soil during the time the plastic was in place, likely due to release of labile NH4-N from soil microbial biomass and subsequent nitrification. Substrate-induced respiration rates were also reduced during solarization, indicating a reduction of microbial biomass. However, these soil indicators were not persistent and should not prohibit the use of this weed management technique by organic growers.

Herpetofaunal Responses to Restoration Treatments of Longleaf Pine Sandhills in Florida

AbstractThe hypothesis that habitat restoration will provide for community reestablishment and the creation of habitat heterogeneity was examined with regards to the herpetofauna of longleaf pine sandhills in northwest Florida. The herpetofaunal response to restoration was examined in fire‐suppressed, hardwood‐dominated areas treated with (1) spring fire; (2) felling or girdling; or (3) a granular form of the herbicide hexazinone. No‐treatment controls were also included. Felling or girdling and herbicide plots were burned for fuel reduction two dormant seasons after initial treatment application. Additionally, data were collected in frequently burned reference sandhills to establish the target condition or restoration goal. Vegetation variables and herpetofaunal capture rates were compared among control and treatment areas. Two similarity indices were utilized to compare treatments and controls with reference sites, to examine restoration success. Restoration treatment effects were observed through reduced hardwood densities. Litter composition varied among control and treatment plots, with leaf litter being highest in areas lacking recent fire. Capture rates of some herpetofaunal species varied significantly among treatment plots. In 1997 similarity indices showed that spring‐burned and felling or girdling plots were more similar to the reference sandhills than the other plots. Treated plots were not significantly different from controls in 1998, a year of a severe drought.

Effects of Hardwood Reduction Techniques on Longleaf Pine Sandhill Vegetation in Northwest Florida

AbstractWe tested whether the intensity of hardwood midstory reduction causes commensurate improvements of herbaceous groundcover in fire‐suppressedPinus palustris(longleaf pine) sandhills. Using a complete randomized block design, we compared the effects of three hardwood reduction techniques (spring burning, application of the ULW®form of the herbicide hexazinone, chainsaw felling/girdling) and a no‐treatment control on plant species richness, and on life form and common species densities at Eglin Air Force Base, Florida, U.S.A., from 1995 to 1998. ULW®and felling/girdling plots were burned for fuel reduction two years after initial treatment application. We also sampled the same variables in frequently‐burned reference sandhills to establish targets for restoration. Spring burns achieved partial topkill of oaks (17.6–41.1% from 1995 to 1998) compared to reductions of 69.1–94% accomplished by ULW®and of 93.2–67.8% by felling/girdling treatments. We predicted that plant species richness and densities of herbaceous groundcover life forms would increase according to the percent hardwood reductions. Predictions were not supported by treatment effects for species richness because positive responses to fire best explained increases in plant richness, whereas ULW®effects accounted for the largest initial decreases. Legumes, non‐legume forbs, and graminoids did not respond to treatments as predicted by the hypothesis. Again, positive responses to fire dominated the results, which was supported by greater herbaceous densities observed in reference plots. Overall, we found that the least effective and least expensive hardwood midstory reduction method, fire, resulted in the greatest groundcover improvements as measured by species richness and herbaceous groundcover plant densities.

002 Effects of Hungavit® Liquid Bio-fertilizer on Leaf Chlorophyll Content, Disease Incidence, and Yield of Tomato, Pepper, and Potato

Hungavit® products contain extracts of earthworm castings and are marketed by BioLife Ltd. as liquid Bio-leaf fertilizer and plant conditioner. Three experimental plots were set up on the AAFC-SCPFRC research farm to evaluate Hungavit®UR, Hungavit®P, and a preparation containing the equivalent amount of N, P, K fertilizer. In Spring 1998, four replicate plots/treatment of tomato, pepper, and potato were set up in a randomized block design. Each plot received the following treatments: untreated control, Hungavit®UR for tomato and pepper or Hungavit®P for potato, and the fertilizer equivalent of Hungavit®UR or P without the organic components. Tomato and pepper plants were treated three times by foliar application at the rate of 5 L/ha using 300 L of water/ha carrier. Leaf chlorophyll contents were measured at 2, 4, and 6 weeks after initial treatment application. Early and total yield were determined. Tomato fruit were evaluated for symptoms of bacterial spot, early blight, anthracnose, and blossom end rot; pepper fruit for bacterial spot; and potato tubers for potato scab. Both Hungavit® and its equivalent fertilizer application increased the chlorophyll readings significantly in at least one measurement for tomato, pepper, and potato plants. Although there were 40% to 55% fewer diseased tomato and pepper fruit in fertilizer and Hungavit® UR treatments, this was not statistically significant from the control treatments. Fertilizer treatment also reduced scab incidence in tubers by 50%, but the overall scab level was very low even in untreated plots. Hungavit® and its fertilizer equivalent had no significant effect on the early or total yield of tomato, pepper, or potato plants.

Denitrification and the Dinitrogen/Nitrous Oxide Ratio as Affected by Soil Water, Available Carbon, and Nitrate

Biological denitrification is affected by many environmental factors that control the amount of N₂ and N₂O entering the atmosphere. This study was conducted to measure the effect of water-filled pore space (WFPS), available C, and soil NO₃ concentration on total denitrification (N₂ + N₂O), using acetylene (C₂H₂) inhibition, and to ascertain if denitrification could be estimated from N₂O measurements in the field using an average N₂/N₂O ratio. Repacked cores of four benchmark soils were brought to 60, 75, and 90% WFPS by applying treatments of glucose-C (0, 180, and 360 kg ha⁻¹) and NO₃-N (0, 50, and 100 kg ha⁻¹). The cores were incubated at 25°C, with and without 100 mL C₂H₂ L⁻¹, for 5 d during which daily gas samples of the headspace were analyzed for N₂O and CO₂. Total N loss due to denitrification generally increased as soil texture became finer and WFPS increased. The only exception to this was the C-amended sand, where N losses up to 26 and 66% were recorded at 60 and 75% WFPS, respectively. Denitrification rates at high N concentrations were quite small in the absence of an available C source but increased with increasing available C (glucose). The N₂/N₂O ratio generally increased with time of incubation after the initial treatment application. The largest ratios (up to 549) were found at the highest available C rate and generally at the highest soil water content. The presence of high NO₃ concentrations apparently inhibited the conversion of N₂O to N₂, resulting in lower N₂/N₂O ratios. Using an average N₂/N₂O ratio for estimation of denitrification from N₂O field measurements cannot be recommended because of the variation in this ratio due to the many environmental factors altered by field management that influence denitrification and the relative production of N₂ and N₂O. Published as Paper No. 9865, Journal Series, Nebraska Agricultural Research Division, Lincoln.