Foliar Treatments of 2,4-Dichlorophenoxyacetic Acid for Control of Common Scab in Potato Have Beneficial Effects on Powdery Scab Control

Prior studies have shown that applications of the synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D) to the foliage of potato plants can reduce common scab. Here field and glasshouse trials suggest that 2,4-D foliar treatments may also reduce the biologically distinct tuber disease, powdery scab. Significant correlations between suppression of common and powdery scab from the field trials suggested an interaction between the two diseases or possible additional broad spectrum mechanisms of enhanced defence against pathogen invasion provided by 2,4-D treatment.

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Determination of optimal timing of 2,4-dichlorophenoxyacetic acid foliar applications for common scab control in potato

Annals of Applied Biology ◽

10.1111/aab.12050 ◽

2013 ◽

Vol 163 (2) ◽

pp. 242-256 ◽

Cited By ~ 3

Author(s):

H.K. Thompson ◽

R.S. Tegg ◽

N.W. Davies ◽

J.J. Ross ◽

C.R. Wilson

Keyword(s):

Common Scab ◽

Optimal Timing ◽

Dichlorophenoxyacetic Acid ◽

Scab Control ◽

2,4 Dichlorophenoxyacetic Acid

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Effects of irrigation regimes on powdery scab disease and yield of potatoes

Australian Journal of Experimental Agriculture ◽

10.1071/ea9860745 ◽

1986 ◽

Vol 26 (6) ◽

pp. 745 ◽

Cited By ~ 10

Author(s):

PA Taylor ◽

SP Flett ◽

RFde Boer ◽

D Marshall

Keyword(s):

Large Scale ◽

Field Experiments ◽

Field Trials ◽

Powdery Scab ◽

Infested Soil ◽

Spongospora Subterranea ◽

Potato Tubers ◽

Potato Plants ◽

Tuber Set ◽

Large Scale Field

The period of susceptibility of potato tubers to powdery scab (Spongospora subterranea) was studied by inoculating potato plants with spores, or by watering plants in infested soil, at different stages of plant development in greenhouse conditions. Maximum susceptibility began about 1 week before the stage when 50% of stolons had swollen to at least 5-mm diameter (tuber set), and ended 3-4 weeks later. With holding irrigation water during this period reduced the severity of powdery scab by 65-75% in field experiments in 1981-82 and 1982-83, but had no apparent effect on disease severity in 3 out of 6 large-scale field trials during 1984-85.

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FIELD MEASUREMENT OF DROPLET DRIFT FROM GROUND SPRAYERS. I. SAMPLING, ANALYTICAL, AND DATA INTEGRATION TECHNIQUES

Canadian Journal of Plant Science ◽

10.4141/cjps78-096 ◽

1978 ◽

Vol 58 (3) ◽

pp. 611-622 ◽

Cited By ~ 25

Author(s):

R. GROVER ◽

L. A. KERR ◽

J. MAYBANK ◽

K. YOSHIDA

Keyword(s):

Meteorological Parameters ◽

Field Trials ◽

Application Rate ◽

Meteorological Station ◽

Dichlorophenoxyacetic Acid ◽

Target Area ◽

Spray Solution ◽

Integration Techniques ◽

Actual Field ◽

2,4 Dichlorophenoxyacetic Acid

A procedure for the evaluation of ground deposits and droplet drift characteristics from a typical farm sprayer under actual field conditions is described. It involves sampling both the ground deposits on the swath and the air-borne cloud mass, the latter at various heights and distances downwind from the target area. The system was evaluated with the commonly used 65° flat-fan nozzles operated at 280 kPa which provided an application rate of 0.56 kg/ha of 2,4-D amine (2,4-dichlorophenoxyacetic acid) in 56 ℓ water/ha. The spray solution also contained a fluorescent dye as a tracer. A portable meteorological station, where a number of meteorological parameters can be measured or recorded during the course of a field trial, is also described. Results of four field trials are presented with discussion regarding on-swath deposit density and its distribution over the swath, off-swath drifting cloud mass and its deposition and decay as a function of distance, and mass balance.

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Influence of growth regulators on skin colour and scab diseases of red-skinned potatoes

Canadian Journal of Plant Science ◽

10.4141/cjps10055 ◽

2010 ◽

Vol 90 (5) ◽

pp. 745-753 ◽

Cited By ~ 13

Author(s):

D. Waterer

Keyword(s):

Abscisic Acid ◽

Growth Regulators ◽

Common Scab ◽

Foliar Application ◽

Colour Change ◽

Field Trials ◽

Streptomyces Scabies ◽

Powdery Scab ◽

Skin Colour ◽

Spongospora Subterranea

A uniform dark red skin colour is desirable in table potatoes; however, the colour of the popular red-skinned cultivar Norland is variable and tends to fade during storage. This study evaluated the potential to enhance skin colour of red potatoes by foliar application of the auxin-type herbicide 2,4-D or long-lasting analogs of the naturally occuring hormone abscisic acid (ABA). In field trials conducted from 2007 to 2009, the plant growth regulators (PGR) were applied to the foliage of Norland and AC Peregrine Red (a new dark red variety) potato plants when the crop was at the tuber set stage. Although the 2,4-D treatments altered the appearance of the foliage they had no consistent impact on yields or tuber shape, but did reduce the average tuber size. Objective and subjective assessments indicated that the 2,4-D treatments altered the skin colour of the tubers both immediately after harvest and after extended cold storage. The degree and nature of the colour change was somewhat dependent on the year, the rate of 2,4-D applied and the cultivar. The change in tuber appearance arising from the 2,4-D treatments was not always considered desirable by consumer panellists. The 2,4-D treatments also reduced tuber damage by common scab (Streptomyces scabies), but tended to increase grade out to powdery scab (Spongospora subterranea). The ABA analogs had no consistent impact on yields, skin colour or disease reaction. Key words: 2,4-dichlorophenoxyacetic acid, abscisic acid, common scab, powdery scab, Streptomyces scabies, Spongospora subterranea

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Auxin-Induced Resistance to Common Scab Disease of Potato Linked to Inhibition of Thaxtomin A Toxicity

Plant Disease ◽

10.1094/pdis-92-9-1321 ◽

2008 ◽

Vol 92 (9) ◽

pp. 1321-1328 ◽

Cited By ~ 24

Author(s):

Robert S. Tegg ◽

Warwick M. Gill ◽

Hannah K. Thompson ◽

Noel W. Davies ◽

John J. Ross ◽

...

Keyword(s):

Common Scab ◽

Foliar Application ◽

Disease Suppression ◽

Dichlorophenoxyacetic Acid ◽

Thaxtomin A ◽

Streptomyces Spp ◽

Streptomyces Scabiei ◽

2,4 Dichlorophenoxyacetic Acid ◽

Sublethal Concentrations

Production of the phytotoxin thaxtomin A by pathogenic Streptomyces spp. is essential for induction of common scab disease in potato. Prior studies have shown that foliar application of sublethal concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) and other auxin or auxin-like compounds significantly reduced severity and occurrence of common scab in subsequently produced tubers. However, the means of disease suppression by these compounds was not known. We confirm the disease suppressive activity of 2,4-D. Detailed tuber physiological examination showed that lenticel numbers, lenticel external dimensions, and periderm thickness and structure, physiological features believed to be critical to Streptomyces scabiei infection, were not substantially changed by 2,4-D treatments, negating a possible mechanism for disease suppression through alteration of these structures. In contrast, our studies show accumulation of 2,4-D in tubers of treated plants occurs and is associated with an enhanced tolerance to thaxtomin A. Applying 2,4-D to cultures of S. scabiei did not significantly alter in vitro growth of the pathogen. Thaxtomin A production by the pathogen was inhibited by 2,4-D, but only at the highest rate tested (1.0 mM), which is at least 200-fold more than is found in 2,4-D treated tubers. These data suggest 2,4-D has no direct effect on the pathogen or its virulence. Confirmatory evidence from studies with Arabidopsis thaliana seedlings demonstrated that the auxins 2,4-D and IAA ameliorate thaxtomin A toxicity. The evidence presented whereby auxin treatment inhibits toxicity of thaxtomin A secreted by the pathogen suggests a novel indirect means of disease suppression.

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The Effect of Picloram Plus 2,4-Dichlorphenoxyacetic Acid on Peanut Growth and Yield

Peanut Science ◽

10.3146/ps19-14.1 ◽

2020 ◽

Vol 47 (2) ◽

pp. 111-114

Author(s):

O.W. Carter ◽

E.P. Prostko

Keyword(s):

Plant Density ◽

Leaf Roll ◽

Field Trials ◽

Growth And Yield ◽

Dichlorophenoxyacetic Acid ◽

Livestock Waste ◽

Significant Yield ◽

Contaminated Irrigation Water ◽

Effect On Yield ◽

2,4 Dichlorophenoxyacetic Acid

ABSTRACT Picloram (4-amino-3,5,6-trichloropicolinic acid) injury, in the form of leaf roll, is often observed in peanut fields due to short crop rotations, contaminated irrigation water, treated hay, and contaminated livestock waste. Limited data on peanut response to picloram is available. Field trials were conducted near Tifton, GA from 2015-2017 to determine the effects of picloram plus 2,4-D (2,4-dichlorophenoxyacetic acid) on peanut growth and yield. Picloram plus 2,4-D was applied to ‘GA-06G' peanut at four different timings: preemergence (PRE), 30 d after planting (DAP), 60 DAP, and 90 DAP. At each timing, three rates of picloram plus 2,4-D were applied including the following: 1/10thX (0.18 + 0.67 kg ai/ha); 1/100thX (0.018 + 0.067 kg ai/ha); and 1/300thX (0.006 + 0.023 kg ai/ha). A non-treated control (NTC) or 0 rate was included for comparison. Peanut plant density was not influenced by any rate or timing of picloram plus 2,4-D. For peanut injury (leaf roll), a significant rate x timing interaction was observed (P=0.047). At 120 DAP, leaf roll was significant for the 1/10thX rate applied at 30, 60, and 90 DAP, the 1/100thX rate applied at 60 and 90 DAP, and for the 1/300thX rate applied at 90 DAP. When averaged over timing, peanut height at 120 DAP was significantly reduced by the 1/10thX and 1/100thX rates. When averaged over rate, peanut height reductions were greatest when picloram plus 2,4-D was applied at 60 DAP. When averaged over timing, only the 1/10thX rate caused significant yield reductions (11%). When averaged over rate, timing had no effect on yield (P=0.5403). Peanut fields unintentionally exposed to picloram plus 2,4-D rates ≤ 1/100thX can exhibit typical injury symptoms but most likely will not experience yield losses.

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Field trials of foliar sprays of 3,5-dichlorophenoxyacetic acid (3,5-D) against common scab on potatoes

Potato Research ◽

10.1007/bf02357292 ◽

1982 ◽

Vol 25 (4) ◽

pp. 347-350 ◽

Cited By ~ 7

Author(s):

A. H. McIntosh ◽

M. M. Burrell ◽

J. H. Hawkins

Keyword(s):

Common Scab ◽

Field Trials ◽

Dichlorophenoxyacetic Acid ◽

Foliar Sprays

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In Vitro Shoot Regeneration from Callus Derived from Marubakaido Apple Rootstock under Different Aluminium Concentrations

HortScience ◽

10.21273/hortsci.33.3.460e ◽

1998 ◽

Vol 33 (3) ◽

pp. 460e-460 ◽

Cited By ~ 1

Author(s):

Marisa F. de Oliveira ◽

Gerson R. de L. Fortes ◽

João B. da Silva

Keyword(s):

Shoot Regeneration ◽

Dichlorophenoxyacetic Acid ◽

Apple Rootstock ◽

Under Five ◽

Significant Difference ◽

Previously Treated ◽

2,4 Dichlorophenoxyacetic Acid ◽

In Vitro Shoot Regeneration

The aim of this work was to evaluate the organogenesis of Marubakaido apple rootstock under different aluminium concentratons. The explants were calli derived from apple internodes treated with either 2,4-dichlorophenoxyacetic acid or pichloram at 0.5 and 1.0 μM and under five different aluminium concentrations (0, 5, 10, 15, 20 mg/L). These calli were then treated with aluminium at 0, 5, 10, 15, and 20 mg/L. It was observed shoot regeneration only for those calli previously treated with pichloram. There were no significant difference among the aluminium concentrations.

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Characterization of the Reproductive Mode in Guayule In Vitro

HortScience ◽

10.21273/hortsci.33.3.483a ◽

1998 ◽

Vol 33 (3) ◽

pp. 483a-483

Author(s):

Roy N. Keys ◽

Dennis T. Ray ◽

David A. Dierig

Keyword(s):

Field Experiments ◽

Reproductive Mode ◽

Dichlorophenoxyacetic Acid ◽

Initial Field ◽

Breeding Lines ◽

Reproductive Modes ◽

Desert Southwest ◽

2,4 Dichlorophenoxyacetic Acid

Guayule (Parthenium argentatum Gray, Asteraceae) is a latex-producing perennial desert shrub that is potentially of economic importance as an industrial crop for the desert Southwest. It is known to possess complex reproductive modes. Diploids are predominantly sexual and self-incompatible, while polyploids show a range of apomictic potential and self-compatibility. This paper describes the development of a relatively rapid and simple technique for characterizing reproductive modes of breeding lines of P. argentatum. Initial field experiments were based on an auxin test used successfully to characterize reproductive mode in the Poaceae. The application of 2,4-dichlorophenoxyacetic acid inhibited embryo formation in P. argentatum, but this was not the case with other auxins tested. Results of field experiments were ambiguous because: 1) the floral structure of P. argentatum is such that auxins might not have penetrated to the ovules, and 2) there was potential self-fertilization by pollen released within isolation bags. Therefore, in vitro culture of flower heads was tested because it provided much better control of environmental conditions, growth regulator application, and pollen release. Auxin alone, or in combination with gibberellic acid or kinetin, inhibited parthenogenesis in vitro. Embryo production did not vary using two substantially different nutrient media. In vitro flower head culture using a (Nitsch and Nitsch) liquid nutrient medium without growth regulators, enabled characterization of the reproductive mode of seven breeding lines, ranging from predominantly sexual to predominantly apomictic. The results of this technique were substantiated using RAPD analyzes of progeny arrays from controlled crosses.

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The role of a metabolic intermediate in the biodegradation of inhibitory substrates

Water Science & Technology ◽

10.2166/wst.1997.0352 ◽

1997 ◽

Vol 36 (10) ◽

pp. 27-36 ◽

Cited By ~ 1

Author(s):

P. Mungkarndee ◽

S. M. Rao Bhamidimarri ◽

A. J. Mawson ◽

R. Chong

Keyword(s):

The Other ◽

Metabolic Product ◽

Dichlorophenoxyacetic Acid ◽

Mutual Inhibition ◽

Metabolic Intermediate ◽

Batch Cultures ◽

Ortho Cresol ◽

2,4 Dichlorophenoxyacetic Acid

Biodegradation of the mixed inhibitory substrates, 2,4-dichlorophenoxyacetic acid (2,4-D) and para-chloro-ortho-cresol (PCOC) was studied in aerobic batch cultures. Each substrate added beyond certain concentrations inhibited the degradation of the other. This mutual inhibition was found to be enhanced by 2,4-dichlorophenol (2,4-DCP) which is an intermediate metabolic product of 2,4-D. When 2,4-DCP accumulated to approximatelY 40 mg/l degradation of all compounds in the mixed 2,4-D and PCOC substrate system was completely inhibited. The degradation of 2,4-D and PCOC individually was also found to be inhibited by elevated concentrations of 2,4-DCP added externally, while PCOC inhibited the utilization of the intermediate.

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