Rating labels

DFR studies are designed and conducted to describe the decline profile of the active ingredient on foliage and/or soil surfaces when applications are made at the proposed label rate. These surfaces are limited to those which can be touched or disturbed by workers and from which residues can be dislodged, deposited on human skin and clothing, or inhaled during the performance of field work and harvesting operations. 

If the label allows for multiple applications of a test substance, then a minimum of two applications at the shortest spray interval are required with the decline measured from the time of the second application. The application rate should be the highest legal label rate for each test site in the lowest gallons of spray solution per acre to provide the highest potential test substance residue levels. 

Gaeddert et al. (1997) found that cross-resistance of the ALS-resistant Palmer amaranth biotype occurred among 16 postemergence ALS herbicides evaluated. Sprague et al. (1995) found that two suspected resistant populations of Palmer amaranth and common waterhemp were resistant to imazethapyr and cross-resistant to the sulfonylureas, chlorimuron and thifensulfuron, at 10 times higher than labeled rates. 

In the case of atrazine, the most widely used triazine, refinement of the conservative Tier I estimate for all populations results in at least a 200-fold reduction in exposure and risk. In addition, the total exposure and risk for atrazine using a Tier III approach is approximately 138000-fold to 450000-fold less than the chronic NOAEL obtained from a rodent study. A 600-fold to 1600-fold difference exists between the NOAEL and maximum theoretical exposure and risk when tolerance values are utilized. Further refinement of the estimate using Tier IV methodology would result in even lower exposure and risk, since this Tier III analysis used data generated from structured field trials (maximum label rate and minimum preharvest interval). 

During the late spring and summer of 1990 and 1991, a USGS study focused on herbicide transport into the atmosphere by various processes. This study was conducted prior to significant label rate reductions for atrazine-containing products. Once in the atmosphere, these compounds can be dispersed by air currents and redeposited by precipitation, snow, and dry deposition on the land surface, lakes, and streams. 

The concept of integrating a chemical herbicide and a microbial herbicide to control a target weed can be illustrated by the example of waterhyacinth, Eichornia crasaipes. The microbial herbicide candidate, Cercospora rodmanii, and sublethal rates of diquat or 3,4-D (0.3% and 6.4% respectively, of the current label rates) can be combined to achieve a better control of waterhyacinth than is possible with the microbial herbicide alone (Charudattan 1985, unpublished data). In this case, the integration is intended primarily to inqprove the efficacy of the microbial herbicide (5). 

Outdoor turf studies are typically conducted in those areas of the country where the product is expected to be used. The highest labeled rate is applied during the time of year that would correspond to local use. Samples from the turf site are obtained prior to and immediately after the pesticide treatment. A typical outdoor study will take many more samples shortly after the application when the pesticide is at its highest concentrations and will thereafter take fewer samples as the study time increases. The samples are taken in time after application to determine how fast the pesticide dissipates after application. However, they additionally measure how well the pesticide transfers from the turf to skin or clothing. 

Your sprayer applies 15 gallons per acre and yonr tank holds 400 gallons. The label rate is 3 pounds of formulation per acre. 

The label rate is 2 pints of pesticide formulation per 100 gallons of water. Your spray tank holds 300 gallons. 

Nunn AD, Schramm E (1981) Analysis of Tc-HIDAs and factors affecting their labeling rate, purity, and stability. J Nucl Med 22-.P52... 

K30. Kleine, T. O., Heinrich, B., and Goetz, K., Biosynthesis of chondroitin sulfate proteins. Isolation of four pools of chondroitin sulfate proteins differing in their solubility and labeling rates with radiosulfate in calf rib cartilage. FEES (Fed. Euf. Biochem. Soc.) Lett. 31, 170-174 (1973). 

In 1994, Termidor 80 WG (Rhdne-Poulenc), the active ingredient of which is fipronil, was installed in Forest Service field tests in a conventional layout. Figure 5 shows the number of years without termite attack for Termidor 80 WG in the concrete slab tests. As of 2003, there were no termite attacks at any of the plots at the four sites, down to the lowest labeled rate of 0.0625% a.i. However, it was noticed that termite pressure in the fipronil control groups at all four sites was less than expected (Figure 6, shaded bars). Termite attack in the control plots rarely surpassed about 30%. The simplest explanation for this was that it was simply a bad time for termites and termite pressures were low, leading to low attack rates at the control plots. If this were the case, it could not be said that the results in the test plots were due to the presence of fipronil it may simply be that there were few termites present. This presented a significant problem for regulatory officials. 

One observation was that the study contained several doses of fipronil, many of them much higher than the labeled rate. Could it be that so much fipronil was applied to the area that it caused attrition of the local termite population Figure 7 illustrates this possibility, the coverage hypothesis. In each replicate, 22 of the 49 available plots contained some dose of fipronil, and an additional 16 plots contained another product and four control plots. In many cases, control plots were nearly completely surrounded by fipronil-treated plots. 

In the menu on the left side, you will see Tray Rating, Section 1, and below Setup there will be Rate-Based. Click on this. In the Rate-Based tab, click on the box labeled Rate-based calculations ... 

Qualitative and quantitative studies on the rate of incorporation of DNA precursors (e.g.,[ H]thymidine) into mt DNA by biochemical and autoradiographic methods and comparison with the average labeling rate in the nnclei of the same cell type. 

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