Patent Grant
11910796
This application claims priority under 35 U.S.C. § 119(b) to Australian Patent Application No. 2019904273 filed on Nov. 13, 2019, the disclosure of which is incorporated herein by reference in its entirety.
The invention relates to novel clopyralid formulations. In particular, the invention is concerned with highly loaded clopyralid formulations, containing two or more salts of clopyralid.
Clopyralid (3,6-dichloro-2-pyridinecarboxylic acid) is a pyridine herbicide suitable for the control of weeds. It has been marketed globally as both solo formulations and as co-formulations with a range of other active ingredients. These formulations are used for control of weeds in a range of agricultural, commercial, home garden and industrial situations.
As a solo formulation, clopyralid liquid formulations are typically soluble liquid (SL) formulations that contain an active ingredient concentration of a single amine salt, such as dimethylammonium (DMA), potassium or triisopropanolamine (TIPA), at a concentration of 300-750 g/L or a mixture of dimethylamine (DM) and monoethylamine salts at 750 g/L. Other SL mixture formulations contain a single amine salt being the monoethanolamine (MEA), triethylamine or triethanolamine.
Existing clopyralid single-salt formulations at the >350-450 g ae/L concentration (600 g/L in commercialized formulations in Australia) have a viscosity specification that is either very low or moderate to high. The DM+monoethylamine clopyralid 750 g/L formulation currently available in Australia has a viscosity of ≈50 cP at 5° C. A low viscosity formulation may be more prone to splashing and poor containment due to spillage. A higher viscosity formulation is by definition more difficult to pour and pump under cold conditions, which are common where clopyralid formulations are used i.e. winter cereal production in Australia. An example of a low viscosity single-salt formulation is the 600 g/L MEA salt, which has a viscosity of <50 cP. An example of a high viscosity single-salt formulation is the 600 g/L TIPA salt, which has a viscosity of up to 800 cP.
High concentration formulations are generally desirable: a highly loaded formulation can deliver the required quantity of active ingredient to a user in a smaller volume and lower weight. For formulators, higher concentration formulations reduce the quantity of formulated product to be produced. There is a saving in packaging, freight costs, storage volume and energy costs and a reduction of waste.
It would be beneficial to provide formulations of clopyralid which are highly loaded to a concentration of 600 g ae/L or more and which have acceptable viscosity at temperatures commonly encountered at application times.
It has been discovered that it is possible to provide clopyralid formulations that are highly loaded yet stable, and which have acceptable viscosity, where clopyralid is present in the form of at least two amine salts, one of which is the monoisopropylamine (MIPA) salt.
Accordingly, the invention provides a clopyralid formulation containing clopyralid at a concentration of at least 600 g ae/L, clopyralid present in the form of at least two amine salts, one of which is the monoisopropylamine salt.
It has been found that clopyralid as the MIPA salt has the advantage of neutralizing the clopyralid acid to create a stable formulation.
Preferably, the second amine salt of clopyralid is the monoethanolamine salt (MEA).
The use of MEA and MIPA as neutralizing agents can also increase the compatibility of clopyralid with other salt-based aqueous concentrates, such as glyphosate and 2,4-D amine. Both MEA and MIPA are acid neutralization agents used in widely used commercial formulations of glyphosate, which can simplify the procurement of raw materials for production of multiple SL formulations.
The components were as set out in Table 1:
Details of the components are set out in Table 2:
To prepare the formulation, 90% of the water was charged into a cooled reaction vessel. The MIPA 70 was added, stirring was commenced and continued with addition of the MEA.
Clopyralid Technical was added slowly, while maintaining the reaction temperature between 40 and 45° C. Upon completion of the Clopyralid Technical addition, the mixture was stirred for a further 30 mins to ensure complete dissolution.
The TERWET 1255 was added while stirring continued and thoroughly blended.
Rhodoline 5338 AG was premixed with the remaining water and then added to the formulation and blended thoroughly.
The clopyralid content was checked and adjusted with more water as required.
The resultant SL formulation was analysed. The analysis is in Table 3:
The formulation was suitable for packaging in a HDPE container with a screw cap closure.
The formulation was subjected to accelerated storage conditions in that HDPE container. It was determined to be stable to heat for 2 weeks at 54° C. and therefore is expected to be shelf stable for at least 2 years.
A 100 mL sample of the formulation which has been subjected to accelerated storage conditions as above was then moved to a centrifuge tube and subjected to seeded cold storage conditions for 7 days at 0° C. The absence of any separated material indicated that the formulation was cold storage stable.
The pH of the embodiment containing the MIPA and MEA salts is 6.70 (1% v/v dilution). The formulation has low persistent foam (0-5 mm after 60 seconds) and a density at 20° C. of 1.25 g/mL. The formulation is stable for all parameters according to the standard CIPAC accelerated testing regime of 14 days at 54° C.
In conclusion, the new clopyralid dual-salt formulation has a novel combination of clopyralid salts including a new salt (MIPA). This formulation enables a stable concentration of 600 g ae/L with a desirable viscosity profile of >50 to <300 cP at 0-25° C.
Formulations of other clopyralid dual salts, being the MIPA salt and another amine salt, may be made in the same general way, as will be apparent to one skilled in the art.
Field trials were conducted to evaluate the efficacy of the SL clopyralid formulation of Example 1, identified as DS-11137.
Field Test 1: Forthside, Tasmania
At Forthside, Tasmania in 2018, a field trial was conducted to evaluate DS-11137 for bioequivalence with the commercially registered formulation “Victory Herbicide 300 SL”, containing 300 g clopyralid/L present as the triisopropanolamine salt, for control of volunteer faba beans (Vicia faba) and blue lupins (Lupinus angustifolius) in wheat cv. Beaufort.
Other products were also tested. The product details are in Table 4:
Treatments included:
Treatments are set out in Table 5:
Treatments were applied as a single foliar application when the wheat had one to two tillers (BBCH 21-22), in a spray volume of 110 L/ha generating a coarse spray quality. Weed control, crop safety and wheat vigour assessments were conducted at 14, 28 and 43 days after application (DAA). Weed counts were carried out at 43DAA.
Volunteer faba bean control is shown in Table 6:
DAA=Days after application
Means followed by the same letter are not significantly different (P=0.05, Duncan's New MRT)
Percent of volunteer faba bean leaf area affected by brownout is shown in Table 7:
Blue Lupin control is shown in Table 8:
Table 9 shows effectiveness of the treatments on each on volunteer faba bean and blue lupin at 43 days after application:
All treatments of Victory 300 SL and DS-11137 offered excellent control of volunteer faba beans and good control of blue lupin.
MCPA LVE 570 EC tank mixed with either Victory 300 SL or DS-11137 offered greater control of blue lupins than either product applied as standalone treatments.
All herbicide treatments mixed well with no issues at the time of spraying. All Victory 300 SL and DS-11137 treatments were safe to wheat cv. Beaufort under the conditions of this trial.
Field Test 2: Sassafras, Tasmania
At Sassafras, Tasmania, a field trial was conducted to evaluate DS-11137 for bioequivalence with Victory 300 SL for control of spear thistle (Cirsium vulgare) in a fallow situation.
The product details are in Table 10:
Treatments included either DS-11137 and Victory 300 SL applied at 7.5, 15 or 21 g ai/ha in tank mixtures with MCPA 500 AC at 500 g ai/ha. (MCPA 500 AC is available through various suppliers.) Treatments were applied as a single foliar application to actively growing spear thistles at the 5 to 6 true leaf growth stage. Applications were made in a spray volume of 110 L/ha with air induction flat fan nozzles generating a coarse spray quality.
Table 11 shows the treatments:
Spear thistle density was assessed prior to treatment application and again at 56 days after application (56DAA). Efficacy against spear thistle was assessed at 14, 28, 42 and 56DAA.
Table 12 details effect on spear thistle:
Table 13 shows necrosis as a percent of leaf area, while Table 14 shows spear thistle counts:
All herbicide treatments caused significant chlorosis to thistles at 28DAA.
All herbicide treatments caused equivalent leaf area necrosis to thistles at 28 and 42DAA.
All herbicide treatments significantly reduced thistle numbers compared to the untreated control.
DS-11137 was bioequivalent to Victory for the control of thistles at all assessments.
All treatments of Victory and DS-11137 gave complete control of spear thistle.
Field Test 3: Moriarty, Tasmania
At Moriarty, Tasmania, a field trial was conducted to evaluate DS-11137 the bioequivalence of Victory Herbicide 300 SL for control of slender thistle (Carduus tenuiflorus) and prickly sowthistle (Sonchus asper) and on pasture safety in a perennial grass pasture.
The products are detailed in Table 15:
As shown in Table 16, treatments included either DS-11137 or Victory Herbicide applied at 15, 21 or 42 g ai/ha in tank mixtures with MCPA 500 SL at 500 g ai/ha. Treatments were applied as a single foliar spray to actively growing thistles at the 4-leaf to large rosette growth stage. Applications were made in a spray volume of 100 L/ha with air induction flat fan nozzles generating a coarse spray quality.
Slender thistle density was assessed prior to treatment application and again at 42 days after application (42DAA), when plant numbers were also assessed. Efficacy against slender thistle was assessed at 14, 27 and 42 days after application (DAA). The results at 42DAA are in Table 17:
All herbicide treatments completely controlled slender thistle at 42DAA and had significant control of prickly sowthistle.
DS-11137 and Victory Herbicide were bioequivalent for effect on slender thistle and prickly sowthistle. Each demonstrated a greater effect on slender thistle at 14DAA when applied at higher rates, though by 27DAA were equivalent at all applied rates.
DS-11137 and Victory Herbicide, at rates of 15 to 42 g ai/ha, each in tank mixtures with MCPA, were safe to the perennial grass pasture under the conditions of this trial with no visible signs of phytotoxicity.
DS-11137 and Victory Herbicide both mixed readily with MCPA with no compatibility issues during application.
Field Test 4: Padthaway, South Australia
At Padthaway in South Australia, a field trial was conducted to evaluate crop safety and efficacy of DS-11137 compared to the registered formulation “Genfarm Clopyralid 600”, when applied to canola cv. 45Y93CL, the weed being volunteer lucerne (Medicago sativa). (Genfarm Clopyralid 600 is supplied by Nutrien Ag Solutions Limited.)
The canola crop was sown in a moist clay loam soil with a knife point press wheel system at a rate of 3.0 kg/ha to a depth of 1.0 cm. The previous crop had been lucerne.
At 65 days after sowing, when the crop stage had reached BBCH scale 16, treatments 2 to 5 in Table 18 below were applied:
Each of Genfarm Clopyralid 600 and DS-11137 is a soluble concentrate with active ingredient Clopyralid at a formulation concentration of 600 g/L. In Genfarm Clopyralid, clopyralid is present as the dimethylamine salt.
Crop vigour and crop phytotoxicity were assessed at 7 days after application (DAA) and again at 14 DAA. Lucerne control was assessed at 7 DAA.
Crop vigour was assessed visually and recorded using a mean percentage scale relative to the untreated control, where 100%=untreated/no damage and 0%=crop death.
Crop phytotoxicity was assessed visually and recorded using a mean percentage scale relative to the untreated control, where 0%=untreated/no damage and 100%=crop death.
Weed control was assessed visually and recorded using a mean percentage scale relative to the untreated control, where 0%=untreated/no control and 100%=complete control/weed death.
The results are set out in Tables 19 to 21:
There was no significant difference between the results for crop vigour.
There was no significant difference between the results for crop phytotoxicity.
Means followed by the same letter do not significantly differ.
As shown in Tables 19 to 21, none of treatments 2 to 5 recorded any significant reduction in crop vigour relative to the untreated control. No symptoms of crop phytotoxicity were evident at 7 or 14 DAA for any of the herbicide treatments. A very low population of lucerne was present across the trial at the time of treatment application. Symptoms of suppression were evident across all herbicide treatments at 7 DAA, consisting of plant wilting and reduced vigour. Although this was mild, both formulations of clopyralid were statistically equivalent, with no difference between application rates.
Field Test 5: Auburn, South Australia
At Auburn in South Australia, a field trial was conducted to evaluate crop safety of DS-11137 compared to the registered formulation “Genfarm Clopyralid 600”, when applied to barley cv. Compass. The previous crop had been wheat.
The barley crop was sown in a moist clay loam soil with a knife point press wheel system at a rate of 90 kg/ha to a depth of 2.5 cm.
At 68 days after sowing, when the crop stage had reached BBCH scale 22, treatments 2 to 5 in Table 22 below were applied:
Each of Genfarm Clopyralid 600 and DS-11137 is a soluble concentrate with active ingredient Clopyralid at a formulation concentration of 600 g/L. In Genfarm Clopyralid, clopyralid is present as the dimethylamine salt.
Crop vigour and crop phytotoxicity were assessed at 7 days after application (DAA) and again at 15 DAA.
Crop vigour was assessed visually and recorded using a mean percentage scale relative to the untreated control, where 100%=untreated/no damage and 0%=crop death.
Crop phytotoxicity (such as chlorosis, necrosis) was assessed visually and recorded using a mean percentage scale relative to the untreated control, where 0%=untreated/no damage and 100%=crop death.
The results are set out in Tables 23 and 24 below.
None of treatments 2 to 5 recorded any significant reduction in crop vigour relative to the untreated control. No symptoms of crop phytotoxicity were evident at 7 or 14 DAA for any of the herbicide treatments. Both formulations of clopyralid were statistically equivalent, with no difference between application rates.
There was no significant difference between the results for crop vigour.
There was no significant difference between the results for crop phytotoxicity.
Field Test 6: York, Western Australia
At York in Western Australia, a field trial was conducted to evaluate DS-11137 for pre-emergence control of volunteer pulses and other broadleaf weeds in wheat (Triticum), while assessing crop safety and yield effects. The efficacy of DS-11137 was compared with that of standard registered herbicides.
The wheat crop (cv. Sceptre) was sown in an untilled seed bed, the soil being grey sand, using a knife point press wheel system at a rate of 70 kg/ha to a depth of 1-1.5 cm. The previous crop had been barley.
Pre-emergently, the following herbicides were applied: Countdown at 2.5 L/ha, Trilogy at 1.6 L/ha and Roundup Ultra Max at 2 L/ha. Countdown and Trilogy are supplied by Adam Australia Pty Limited; Roundup Ultra Max is supplied by Bayer CropScience Pty Limited.
Treatments in the trial, set out in Table 25, were applied pre-planting and incorporated by sowing:
To assess crop safety, the number of wheat plants per square metre were counted at 31 days after sowing (DAS). The results are in Table 26 below. Crop phytotoxicity was assessed at 31 DAS and again at 55 DAS: see Table 27. Crop vigour assessments for the same period are shown in Table 28.
There were no significant differences in crop emergence in response to the treatments.
There were no phytotoxic effects.
There was no reduced vigour observed in response to any treatment.
The primary target species in the trial were volunteer pulses including chickpeas (Cicer arietinum), field peas (Pisum sativum) and lupins (Lupinis) in wheat. Tables 29, 30 and 31 show percent control of each of these, assessed at 55 DAS and 79 DAS.
Means followed by the same letter are not significantly different.
Table 29 shows that DS-11137 demonstrated strong control over chickpeas and performed significantly better than Gallery.
Means followed by the same letter are not significantly different.
Table 30 shows that DS-11137 demonstrated significant control over field peas, once again performing significantly better than Gallery.
Means followed by the same letter are not significantly different.
Table 31 shows that DS-11137 demonstrated comparable control over lupins, compared with Callisto and superior performance compared to Gallery. All treatments decreased in efficacy over lupins from 55 DAS to 79 DAS.
Field Test 7: Roseworthy, South Australia
A field trial was conducted to evaluate DS-11137 for pre-emergence control of volunteer pulses: lentil (Lens culinaris), field peas (Pisum sativum arvense) and chickpea (Cicer arietinum) in wheat cv. Sceptre.
These treatments were compared to registered herbicide Gallery and Adama Mesoflex (a suspension concentrate formulation of 480 g/L of Mesotrione, available from Adama Australia Pty Limited). The treatments, which are set out in Table 32, were applied pre-planting and incorporated by sowing (IBS).
The wheat crop (cv. Sceptre) was sown in a moist clay loam soil with a knife point press wheel system at a rate of 100 kg/ha to a depth of 2 to 3 cm.
At 25 days after sowing, when the crop stage had reached BBCH scale 12, crop emergence was noted. At 26 days after sowing, crop vigour and phytotoxicity were assessed, as well as weed control. At 56 days after sowing, the crop stage had reached BBCH scale 22; crop vigour and phytotoxicity were assessed, as well as weed control.
Crop emergence was assessed by counting 6 times per plot the number of plants along 50 cm of row and recording the result as the number of plants/m row.
Crop vigour was assessed visually and recorded using a mean percentage scale relative to the untreated control, where 100%=untreated/no damage and 0%=crop death.
Crop phytotoxicity was assessed visually and recorded using a mean percentage scale relative to the untreated control, where 0%=untreated/no damage and 100%=crop death.
Weed control was assessed visually and recorded using a mean percentage scale relative to the untreated control, where 0%=untreated/no control and 100%=complete control/weed death, relative to the untreated control.
The results are set out in Tables 33 to 38:
There were no significant differences in crop emergence in response to the treatments.
Means followed by the same letter are not significantly different.
There was no reduced vigour observed in response to any treatment. Crop vigour for DS11137 at 45 g ai/ha was equivalent to the untreated control, Mesoflex and registered herbicide Gallery.
Means followed by the same letter are not significantly different.
There were no symptoms of crop phytotoxicity at 26 DAS. DS11137, Gallery and Mesoflex were not associated with any significant crop phytotoxicity compared to the untreated control at 56DAS.
Means followed by the same letter are not significantly different.
DS11137 recorded almost complete control of volunteer lentil at both 26 and 56 DAS and was significantly more effective than both Gallery and Mesoflex.
Means followed by the same letter are not significantly different.
For field peas, DS11137 provided a high level of control that was statistically equivalent to the other best performing treatments and significantly higher than Gallery and Mesoflex at 56 DAS.
Means followed by the same letter are not significantly different.
D511137 recorded almost complete control of chickpea at 56 DAS and was significantly more effective than Mesoflex and Gallery.
The above results show that DS11137, applied IBS at 45 g ai/ha, did not record a significant reduction in crop vigour compared to the untreated control or any significant crop phytotoxic symptoms, but recorded a high level of control of volunteer lentil (99%), field pea (94%) and chickpea (100%).
It will be appreciated from the data in the above tables that the efficacy of the formulations of the invention is at least comparable to that of prior art formulations and in many cases superior to prior art formulations. The formulations of the invention, being more concentrated, are more efficient.
In addition, an increase in concentration from 300 g ae/L to 600 g ae/L of clopyralid represents a 50% reduction in the volume of material to be formulated, transported, stored and applied by the end user.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019904273 | Nov 2019 | AU | national |
| Number | Date | Country |
|---|---|---|
| 102283196 | Dec 2011 | CN |
| 102960344 | Mar 2013 | CN |
| Entry |
|---|
| Espacenet partial translation of CN 102960344 retrieved Oct. 19, 2022. |
| Google patents partial translation of CN 102960344 retrieved Sep. 1, 2023. |
| Number | Date | Country | |
|---|---|---|---|
| 20210137111 A1 | May 2021 | US |
