Response of Concord Grapes (Vitis labrusca) to 2,4-D in Irrigation Water

Weed Science ◽  
1984 ◽  
Vol 32 (4) ◽  
pp. 455-459 ◽  
Author(s):  
Richard D. Comes ◽  
Louis Y. Marquis ◽  
Allen D. Kelley

In field studies 0.1 ppmw ae or less 2,4-D [(2,4-dichlorophenoxy)acetic acid] applied by sprinklers in 5.1 cm of water over 8 h did not affect the number or dry weight of leaves or length of canes of 1-yr-old Concord grape plants (Vitis labruscaL.). A second application at 0.01 ppmw or higher to the same plants 1 yr later reduced growth of leaves, canes, and trunk. Combined effects of root pruning (required to position plants for treatment the second year) and 2,4-D probably account for this apparent anomaly. When 2,4-D was applied annually at 1.0 ppmw or less to established plants for three consecutive years, growth, yield, and fruit quality were not affected. No residues of 2,4-D were detected in the fruit at harvest (detection limit 0.05 ppmw). Grapes treated with 1.0 ppmw 2,4-D developed moderate injury symptoms.

Weed Science ◽  
1988 ◽  
Vol 36 (6) ◽  
pp. 775-778 ◽  
Author(s):  
Prasanta C. Bhowmik ◽  
Krishna N. Reddy

Field studies were conducted to determine the effects of various barnyardgrass populations on growth, yield, and nutrient concentration of transplanted “Jetstar’ tomato. Barnyardgrass densities at 16, 32, and 64 plants/m tomato row were tested in 1982 and 1983. Barnyardgrass shoot fresh weights/unit area increased as density increased. Fresh weight of barnyardgrass shoots ranged from 17 100 kg/ha at 16 plants/m of row to 35 500 kg/ha at 64 plants/m of row. At the vegetative stage, tomato shoot dry weight was unaffected by barnyardgrass. As crop growth progressed, tomato shoot dry weight decreased at all barnyardgrass densities. Season-long interference of barnyardgrass reduced marketable tomato fruit number and fruit weight at all densities compared to weed-free plots. Reductions in marketable fruit weight ranged from 26% to 16 plants/m row to 84% at 64 plants/m row. In 1982, concentrations of N, P, K, Ca, and Mg in tomato shoots were unaffected by season-long interference of barnyardgrass at all densities. However, in 1983, concentrations of N and K decreased and concentration of P increased in tomato leaves as the density of barnyardgrass increased. Concentrations of Ca and Mg in tomato leaves were unaltered by barnyardgrass density.


2002 ◽  
Vol 65 (10) ◽  
pp. 1632-1636 ◽  
Author(s):  
MIN-SUK RHEE ◽  
RICHARD H. DOUGHERTY ◽  
DONG-HYUN KANG

The combined effects of acetic acid and mustard flour were investigated to ascertain their impact on Escherichia coli O157:H7 stored at 5 and 22°C. Samples were prepared with various concentrations of acetic acid (0, 0.25, 0.5, 0.75, and 1% [vol/vol]) combined with 10% (wt/vol) Baltimore or Coleman mustard flour and 2% (fixed; wt/vol) sodium chloride. An acid-adapted mixture of three E. coli O157:H7 strains (106 to 107 CFU/ml) was inoculated into prepared mustard samples that were stored at 5 and 22°C, and samples were assayed periodically for the survival of E. coli O157:H7. The numbers of E. coli O157:H7 were reduced much more rapidly at 22°C than at 5°C. E. coli O157:H7 was rapidly reduced to below the detection limit (<0.3 log10 CFU/ml) after 1 day at 22°C, whereas it survived for up to 5 days at 5°C. There was no synergistic or additive effect with regard to the killing of E. coli O157:H7 with the addition of small amounts of acetic acid to the mustard flour. When stored at 5°C, mustard in combination with 0.25 (M-0.25), 0.5 (M-0.5), and 0.75% (M-0.75) acetic acid exerted less antimicrobial activity than the control (M-0). The order of lethality at 5°C was generally M-0.25 = M-0.5 < M-0.75 = M-0 < M-1. The addition of small amounts of acetic acid (<0.75%) to mustard retards the reduction of E. coli O157:H7. Statistical reduction in populations of E. coli O157:H7 (P < 0.05) was enhanced relative to that of the control (mustard alone) only with the addition of 1% acetic acid. This information may help mustard manufacturers to understand the antimicrobial activity associated with use of mustard flour in combination with acetic acid.


Weed Science ◽  
1985 ◽  
Vol 33 (3) ◽  
pp. 353-357
Author(s):  
Jodie S. Holt ◽  
Steven R. Radosevich ◽  
Walter L. Graves

Field studies were established in 1974 and 1975 at various locations in San Diego County, CA, to evaluate several herbicides for the control of chamise (Adenostoma fasciculatumH.&A.) and redshank chamise (Adenostoma sparsifoliumTorr.). Herbicide effects on vegetation were reevaluated in 1982. Plots originally treated with 2.2 or 4.5 kg ae/ha of glyphosate [N-(phosphonomethyl)glycine] had virtually no chamise regrowth 8 yr after treatment. The herbicides 2,4-D [(2,4-dichlorophenoxy)acetic acid], combinations of 2,4-D with 2,4,5-T [(2,4,5-trichlorophenoxy)acetic acid] or dichlorprop [2-(2,4-dichlorophenoxy) propionic acid], fosamine [ethyl hydrogen (aminocarbonyl)phosphonate], triclopyr {[(3,5,6-trichloro-2-pyridinyl)oxy] acetic acid}, tebuthiuron {N-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-N,N′-dimethylurea}, and picloram (4-amino-3,5,6-trichloropicolinic acid) had no long-term effects on chamise. Soil collected in 1982 from glyphosate-treated plots contained similar numbers of chamise seeds but fewer seeds of other species compared to untreated plots. Canopy cover of redshank chamise was similar in treated and untreated plots after 8 yr. These results document the effectiveness of glyphosate in killing the underground root-crown of chamise, which prevented sprouting, but not redshank chamise.


Weed Science ◽  
1982 ◽  
Vol 30 (4) ◽  
pp. 349-351 ◽  
Author(s):  
Prasanta C. Bhowmik

Five field experiments were conducted to evaluate effectiveness of postemergence herbicidal treatments. Amitrole (3-amino-s-triazole) at 1.1 kg ai/ha and picloram (4-amino-3,5,6-trichloropicolinic acid) at 0.6 kg ai/ha reduced stands of common milkweed (Asclepias syriaca L.) for a 4-yr period. Glyphosate [N-(phosphonomethyl)glycine] at 2.2 kg ai/ha reduced stands of milkweed for two to three growing seasons. Glyphosate or amitrole applied in June (early bud stage) more effectively reduced milkweed stands in the second year than did the herbicides when applied in August (post-flowering stage). Treatments of 2,4-D [(2,4-dichlorophenoxy)acetic acid], 2,4,5-T [(2,4,5-trichlorophenoxy)acetic acid], and dicamba (3,6-dichloro-o-anisic acid) did not reduce stands of common milkweed.


Author(s):  
Saikat Gantait ◽  
Manisha Mahanta

Abstract Background Gerbera jamesonii Bolus ex Hooker f. (African daisy) is listed among the top five most important ornamental plants in the global floricultural industry. To satisfy its demand, the floriculture industry relies on reproducible and effective propagation protocol while retaining the genetic uniformity of G. jamesonii. The present study, for the first time, reports the potential of picloram for enhanced induction of organogenic calli from leaves of G. jamesonii and its high-frequency indirect regeneration. Results The fastest induction of calli with maximum fresh and dry weight was recorded in the Murashige and Skoog (MS) semisolid medium supplemented with 1 mg/l picloram. In addition, callus induction was observed in 2,4-dichlorophenoxy acetic acid- and α-napthaleneaceticacid-supplemented media but with delayed response and reduced fresh and dry weight. The proliferated calli were transferred to shoot induction media containing MS salt and 0.5–1 mg/l N6-benzylaminopurine, kinetin, or thidiazuron. A mean number of ~6 shoots per callus were developed after 5 days of culture in the MS medium supplemented with 1 mg/l kinetin, with a mean length of 5.2 cm. Successful rooting of shoots was achieved in the MS medium fortified with 1.5 mg/l indole-3-acetic acid, wherein the earliest root initiation (~5 days), as well as the maximum number (~9) and length (~4.8 cm) of roots, were recorded. Complete plantlets were primarily acclimatized in sand before being transferred to a mixed substrate (of soil, sand, tea leaf waste, and cow urine) that secured >90% survival and further growth of the plantlets. Eventually, clonal fidelity of the in vitro regenerants assessed via inter-simple sequence repeats (ISSR) primers exhibited a monomorphic banding patterns that suggested genetic integrity within the plantlets as well as with their mother plant. Conclusions The results of the present study should be of interest for commercial propagation and mutagenesis- as well as genetic transformation-related research.


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. 116-118 ◽  
Author(s):  
A. G. Carson ◽  
J. D. Bandeen

Field studies were conducted to evaluate the effectiveness of one, two, and three annual applications of atrazine [2-chloro-4-(ethylamino) −6-(isopropylamino)-s-triazine], 2,4-D [(2,4-dichlorophenoxy) acetic acid], dicamba (3,6-dichloro-o-anisic acid), and a three way mix of dicamba, mecoprop [2-[(4-chloro-o-tolyl) oxy]propionic acid], and 2,4-D at a ratio of 7:5:20 at different stages of development for the control of Canada thistle [Cirsium arvense(L.) Scop.]. Two consecutive annual applications in all atrazine treatments achieved the same level of control as cultivation every 5 weeks. In the year of the last treatment, Canada thistle was controlled with two or more consecutive annual applications of the hormone-type herbicides (2,4-D, dicamba, and the three way mix); however, in the year following the last treatment, regrowth occurred.


Weed Science ◽  
1970 ◽  
Vol 18 (4) ◽  
pp. 481-483 ◽  
Author(s):  
M. Coburn Williams ◽  
L. B. Kreps

Several herbicides were evaluated for control of western false hellebore (Veratrum californicumDurand). The dimethylamine salt and propylene glycol butyl ether esters of (2,4-dichlorophenoxy)acetic acid (2,4-D), potassium salt of 2-[(4-chloro-o-tolyl)oxy]propionic acid (mecoprop), and the butoxy ethanol ester of 2-(2,4,5-trichlorophenoxy)propionic acid (silvex) controlled 95 to 99% of the plants when applied at 2 lb/A followed by 2 lb/A of the dimethylamine salt of 2,4-D the second year. Optimum control was achieved when plants were treated after the last leaf had expanded and before flower bud initiation.


HortScience ◽  
2003 ◽  
Vol 38 (3) ◽  
pp. 367-372 ◽  
Author(s):  
Elizabeth A. Wahle ◽  
John B. Masiunas

Greenhouse hydroponics and field experiments were conducted to determine how nitrogen (N) fertilizer treatments affect tomato (Lycopersicon esculentum Mill.) growth, yield, and partitioning of N in an effort to develop more sustainable fertilization strategies. In a hydroponics study, after 4 weeks in nitrate treatments, shoot dry weight was five times greater at 10.0 than at 0.2 mm nitrate. An exponential growth model was strongly correlated with tomato root growth at all but 0.2 mm nitrate and shoot growth in 10 mm nitrate. Root dry weight was only 15% of shoot biomass. In field studies with different population densities and N rates, height in the 4.2 plants/m2 was similar, but shoot weight was less than in the 3.2 plants/m2. At 12 weeks after planting, shoot fresh weight averaged 3.59 and 2.67 kg/plant in treatments with 3.2 and 4.2 plants/m2, respectively. In 1998, final tomato yield did not respond to N rate. In 1999, there was a substantial increase in fruit yield when plants were fertilized with 168 kg·ha-1 N but little change in yield with additional N. Nitrogen content of the leaves and the portion of N from applied fertilizer decreased as the plants grew, and as N was remobilized for fruit production. Both studies indicate that decreasing N as a way to reduce N loss to the environment would also reduce tomato growth.


Weed Science ◽  
1970 ◽  
Vol 18 (1) ◽  
pp. 77-80 ◽  
Author(s):  
R. M. Adamson ◽  
R. H. Turley

Effects of the alkanolamine salt of (2,4-dichlorophenoxy) acetic acid (2,4-D) and sodium salt of 4-hydroxy-3,5-diiodobenzonitrile (ioxynil) upon seedlings of Chewings fescue (Festuca rubra var. commutata Gaud.), Park bluegrass (Poa pratensis L.), and Highland bentgrass (Agrostis tenuis Sibth.) were evaluated in growth room and field studies. In the former, injury to Park bluegrass from both 1 and 3 lb/A applications of 2,4-D was severe with pronounced but less marked effects on fescue and bentgrass. Results were similar from applications shortly after emergence and after clipping the grass. Negligible injury was caused by 1 lb/A of ioxynil. In the field, ioxynil gave better weed control than 2,4-D when applied at a seedling height of 1 inch. No injury was caused by ioxynil. Although 2,4-D reduced yields from early clippings, there was marked recovery, even at 3 lb/A. No treatments significantly affected plant stand.


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