A Method for Simulating Subsurface Disposal of Herbicides

Weed Science ◽  
1977 ◽  
Vol 25 (4) ◽  
pp. 368-372
Author(s):  
J.M. Cupello ◽  
A.L. Young ◽  
J.C.H. Smith

Specially designed growth boxes were used to simulate field subsurface injection of phenoxy herbicides. Sorghum (Sorghum vulgarePers.) seedlings were grown in stainless steel containers (inserts) which were placed in plexiglass boxes containing a soil layer that had received 2,240 kg/ha of a 50:50 mixture of then-butyl esters of 2,4-D [(2,4-dichlorophenoxy)-acetic acid] and 2,4,5-T [(2,4,5-trichlorophenoxy)-acetic acid]. Plant height data were collected periodically for all treatments. Subsurface herbicide application to both intact and cut root systems significantly altered root growth. Plants with treated, intact root systems showed retarded growth which became more pronounced with time. Plants whose root systems were treated, and cut on day 22, showed an initial acceleration of growth; a trend which eventually reversed itself and resulted in control plant height exceeding that of treated plants.

Weed Science ◽  
1973 ◽  
Vol 21 (6) ◽  
pp. 556-560 ◽  
Author(s):  
J. D. Altom ◽  
J. F. Stritzke

The degradation rates of 2,4-D [(2,4-dichlorophenoxy)acetic acid], dichlorprop [2-(2,4-dichlorophenoxy)propionic acid], 2,4,5-T [(2,4,5-trichlorophenoxy)acetic acid], silvex [2,(2,4,5-trichlorophenoxy)propionic acid], dicamba (3,6-dichloro-o-anisic acid), and picloram (4-amino-3,5,6-trichloropicolinic acid) were determined in three soils. Herbicide breakdown was proportional to herbicide concentration, so half life of the various herbicides was calculated from linear regression of the logarithm transformed residue data. The average half life for 2,4-D, dichlorprop, silvex, 2,4,5-T, dicamba, and picloram were, respectively, 4 days, 10 days, 17 days, 20 days, 25 days, and greater than 100 days. The rate of degradation of 2,4-D was the same in all three soils, but for the other herbicides it was consistently faster in soil removed from under grass vegetation than from under trees.


Weed Science ◽  
1972 ◽  
Vol 20 (3) ◽  
pp. 226-229 ◽  
Author(s):  
A. S. Hamill ◽  
L. W. Smith ◽  
C. M. Switzer

The foliar uptake of 4-amino-3,5,6-trichloropicolinic acid (picloram) and its phytotoxicity in mixtures with several phenoxy herbicides were studied using bean (Phaseolus vulgaris L. ‘Red Kidney’). The greatest accumulation of picloram occurred in the growing point, stem, and axillary buds. Transport from the treated leaf occurred within 6 hr and continued for at least 7 days. The effectiveness of herbicide combinations containing picloram was related to the particular plant part measured. A synergistic reduction in fresh and dry red kidney bean weight was obtained with (2,4-dichlorophenoxy) acetic acid (2,4-D) or 2-[(4-chloro-o-tolyl)oxy]propionic acid (mecoprop) when applied in combination with picloram, whereas 4-(2,4-dichlorophenoxy)butyric acid (2,4-DB) and picloram gave an antagonistic response. An investigation of the antagonistic reaction of 2,4-DB with picloram indicated that picloram prevented the movement of 2,4-DB, while 2,4-DB increased both the distribution and the amount of picloram translocated from the point of application.


Weed Science ◽  
1973 ◽  
Vol 21 (2) ◽  
pp. 141-144 ◽  
Author(s):  
L. Thompson ◽  
D. B. Egli

Seed were harvested from soybean [Glycine max(L.) Merr. ‘Cutler’] plants treated at flowering and pod filling with (2,4-dichlorophenoxy)acetic acid (2,4-D), 4-(2,4-dichlorophenoxy)butyric acid (2,4-DB), and 3,6-dichloro-o-anisic acid (dicamba). Progeny of plants treated at flowering with 2,4-D and 2,4-DB or at pod filling with the lowest rate were normal. When higher rates were applied at pod filling, these phenoxy herbicides caused appreciable injury to the progeny in the form of reduced emergence and dry weight and malformed unifoliate leaves. Dicamba was much more injurious to the progeny of treated plants than 2,4-D and 2,4-DB. Even at low rates dicamba caused reduced germination, emergence, and dry weight and malformed first trifoliate leaves.


Weed Science ◽  
1975 ◽  
Vol 23 (2) ◽  
pp. 119-126 ◽  
Author(s):  
Shane S. Que Hee ◽  
Ronald G. Sutherland

The volatilities of iso and normal butyl esters of 2,4-D [(2,4-dichlorophenoxy)acetic acid] in a commercial formulation applied as thin films on pyrex and as aqueous droplets on pyrex and leaf surfaces increased directly with the available surface area/applied dose ratio (Q), and inversely with the adsorptive and absorptive characteristics of the surface, under the same conditions of temperature (39 ± 1.5 C), relative humidity (RH) (0%), geometry, airflow rate (750 ± 7 ml/min) and light. Partial pressures and rates of volatilization were computed. Herbicide in droplets below 200μin diameter tended to volatilize faster than it penetrated, but the reverse occurred above this diameter.


Weed Science ◽  
1970 ◽  
Vol 18 (2) ◽  
pp. 276-278 ◽  
Author(s):  
John D. Nalewaja

Wheat (Triticum aestivum L., var. Selkirk) was most susceptible at the late tiller stage to 4-amino-3,5,6-trichloropicolinic acid (picloram) as determined from weekly applications in the field and the degree of injury increased with rate of picloram. Wheat injury from picloram was manifested by lower kernel yield, greater protein content in the kernels, and reduction in plant height. A reduction in the length of the stem occurred while the length of the flag leaf sheath was not affected. Picloram increased kernel size in 1966 but reduced it in 1965. Picloram did not influence germination of kernels from treated plants. The addition of (2,4-dichlorophenoxy)acetic acid (2,4-D) to picloram tended to increase wheat injury at the 2 to 4-leaf stage.


2020 ◽  
Vol 8 (3) ◽  
pp. 318-322
Author(s):  
Abdul Samad Soomro ◽  
Abdul Sattar Soomro ◽  
Shabana Naz Mazari

The exercise of using (PGRs), especially Gibberellic acid and in field of agriculture has become commercialized in some of the country including Pakistan. Number of different crops are being treated by farmers mostly vegetables; currently evaluated in rice crop through foliar application at different intervals to evaluate their efficiency at different doses. Results revealed that there was no significant difference in crop maturity compared with control. Plant height was variable among treated plots, highest plant height was recorded (121.2cm) in 2017-18 experiment in T-3 Gibberellic acid @ 12grams/acre while minimum (96.2cm) in 2016-17 in T-7 Control. Tillers/hill was increased, and maximum counted 18.5/hill in T-3 Gibberellic acid @ 10gms/acre whereas 11.9/hill was recorded in T-7 Control. Grain filling was obvious recorded with significance; counted 83 percent in T-5 Naphthalene acetic acid treated 100ml/acre whereas average minimum (71.3%) was recorded in T-7 Control. Not only plant development was modified by the treatments but yield was also increased average maximum (3228kgs/acre) with 19.61 percent was recorded in T-5 Naphthalene acetic acid @ 100ml/acre.  Int. J. Appl. Sci. Biotechnol. Vol 8(3): 318-322


Weed Science ◽  
1973 ◽  
Vol 21 (3) ◽  
pp. 238-241 ◽  
Author(s):  
P. N. P. Chow ◽  
R. D. Dryden

Seven cultivars of spring wheat (Triticum aestivum L.) and one hybrid (Triticale hexaploid Lart. ‘Rosner’) were evaluated in seven field experiments and one greenhouse test for tolerance to the postemergence application of the sodium salt of trichloroacetic acid (TCA) for the control of green foxtail (Setaria viridis (L.) Beauv.). The control of green foxtail and broadleaf weeds was also studied. Of the seven cultivars, ‘Pitic 62’ and ‘Stewart’ were most susceptible to injury from TCA. All other cultivars were tolerant to 0.56 kg/ha. ‘Selkirk’ appeared to be most resistant. With ‘Manitou’ 0.56 kg/ha of TCA gave about 50% control of green foxtail. Higher rates permitted increased growth of broadleaf weeds as a result of reduced competition from injured wheat and green foxtail. Control of all weeds was improved by 10 to 30% when TCA was applied with one of the phenoxy herbicides. Satisfactory crop tolerance and good weed control was achieved with 0.56 kg/ha TCA and 0.56 kg/ha of the amine salt of (2,4-dichlorophenoxy)acetic acid (2,4-D).


Weed Science ◽  
1969 ◽  
Vol 17 (3) ◽  
pp. 373-376 ◽  
Author(s):  
R. W. Bovey ◽  
H. L. Morton ◽  
J. R. Baur

Herbicides 4-amino-3,5,6-trichloropicolinic acid (picloram) and 5-bromo-3-sec-butyl-6-methyluracil (bromacil) effectively controlled live oak (Quercus virginianaMill.) when applied in the spring and fall in south Texas. A mixture of picloram plus (2,4,5-trichlorophenoxy)acetic acid (2,4,5-T) also was effective. Higher rates of bromacil were required than for picloram or picloram plus 2,4,5-T for effective control. Bromacil was more injurious to herbaceous vegetation. The phenoxy herbicides (2,4-dichlorophenoxy)acetic acid (2,4-D) and 2,4,5-T were ineffective.


HortScience ◽  
1990 ◽  
Vol 25 (5) ◽  
pp. 569-571 ◽  
Author(s):  
A. Raymond Miller ◽  
Craig K. Chandler

A protocol was developed for excising and culturing cotyledon explants from mature achenes of strawberry (Fragaria × ananassa Duch.). Cotyledon explants formed callus with multiple shoot buds on agar-solidified Murashige and Skoog media containing several combinations of hormones (1 μm 2,4-D; 10 μm 2,4-D; 1 μm BA + 1 μm 2,4-D; 1 μm BA + 10 μm 2,4-D; 5 μm BA; 5 μm BA + 1 μm 2,4-D; 5 μm BA + 10 μ m 2,4-D; 5 μ m BA + 5 μm NAA; 5 μ m BA + 15 μ m NAA). After three subcultures, only tissues maintained on the medium containing 5 μm BA + 5 μm NAA continued to form shoots. Tissues transferred to other media eventually died (1 μm 2,4-D; 1 μ m BA + 10 μ m 2,4-D; 5 μ m BA; 5 μ m BA + 1 μ m 2,4-D), became unorganized (1 μm BA + 1 μm 2,4-D; 5 μm BA + 10 μm 2,4-D; 5 μm BA + 15 μm NAA), or formed roots (10 μm 2,4-D). Whole plantlets were produced by transferring callus with buds to medium lacking hormones. The rapid regeneration of clonal plantlets from cotyledon explants may be useful for reducing variability in future developmental studies. Chemical names used: N-(phenylmethyl)-1H-purin-6-amine (BA); (2,4-dichlorophenoxy) acetic acid (2,4-D); and 1-naphthaleneacetic acid (NAA).


Crop Science ◽  
1986 ◽  
Vol 26 (2) ◽  
pp. 376-377 ◽  
Author(s):  
Cecil Regier ◽  
R. E. Dilbeck ◽  
D. J. Undersander ◽  
J. E. Quisenberry

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