scholarly journals Foliar Application of Liquid Urea-triazone-based Nitrogen Fertilizers and Crop Safety

1993 ◽  
Vol 3 (4) ◽  
pp. 442-444 ◽  
Author(s):  
J.G. Clapp

Urea-triazone-based nitrogen (N) solutions were evaluated for potential leaf injury on agronomic and horticultural crops at 61 commercial grower sites throughout the United States. Poliar spray solutions containing triazone N were used at concentrations ranging from 1.5% to 15.7%. Safe N concentrations for urea-triazone-based N products ranged from 1.5% for crops such as sweet corn, apple, cherry, and pear, and up to 15.7% for nursery root stocks. Urea-triazone-based N solutions were found to be much safer on crop foliage than ammonium-, nitrate-, and/or all urea-based foliar fertilizer products than reported in the literature.

Plant Disease ◽  
2000 ◽  
Vol 84 (8) ◽  
pp. 901-906 ◽  
Author(s):  
Jerald K. Pataky ◽  
Lindsey J. du Toit ◽  
Noah D. Freeman

Maize accessions were evaluated in 1997, 1998, and 1999 to identify additional sources of Stewart's wilt resistance and to determine if reactions differed among accessions collected from various regions of the United States and throughout the world. The distributions of Stewart's wilt reactions rated from 1 (no appreciable spread of symptoms) to 9 (dead plants) were relatively similar among groups of accessions from all regions of the world except for those from the Mid-Atlantic/Ohio River Valley region of the United States, the southern United States, and the northeastern United States. The mean and median Stewart's wilt rating for 1,991 accessions evaluated in 1997 was 4. The mean Stewart's wilt rating for 245 accessions collected from the Mid-Atlantic/Ohio River Valley region was 3.1, which was significantly lower than that for accessions from all other regions. The mean rating for accessions from the southern United States was 3.7, which also was lower than mean ratings for accessions from all other regions. Ratings from trials in 1997 and 1998 were highly correlated (r = 0.87) for 292 accessions and 15 sweet corn hybrid checks evaluated in both years. Of 20 accessions rated below 2 in 1997 and 1998, seven were from Virginia, seven were from the Ohio River Valley or central Corn Belt of the United States, four were from the northern or western Corn Belt of the United States, and two were from Spain. Ratings for these accessions ranged from 1.7 to 3.1 in 1999. Ratings ranged from 2.6 to 3.7 for F1 hybrids of these accessions crossed with one of two susceptible sweet corn inbreds, CrseW30 or Crse16, which were rated 5.7 and 5.4, respectively. Based on the reactions of this collection of germ plasm, it appears that high levels of Stewart's wilt resistance are prevalent only among accessions collected from areas where the disease has been endemic for several years, whereas moderate levels of resistance can be found in accessions collected from nearly everywhere in the world.


Plant Disease ◽  
2004 ◽  
Vol 88 (8) ◽  
pp. 909-909 ◽  
Author(s):  
S. N. Wegulo ◽  
S. T. Koike ◽  
M. Vilchez ◽  
P. Santos

During February 2004, diseased double impatiens (Impatiens walleriana) plants were received from a commercial grower in southern California. The upper surfaces of symptomatic leaves were pale yellow with no distinct lesions. Diseased leaves later wilted, and severely affected leaves abscised from the stem. At the nursery, only double impatiens plants in the Fiesta series were infected, and some cultivars were more heavily infected than others. Disease incidence in cv. Sparkler Hot pink was nearly 100%. The interior of infected leaves was colonized by coenocytic mycelium. A conspicuous white growth was observed only on the underside of leaves. Sporangiophores were hyaline, thin walled, emergent from stomata, and had slightly swollen bases. Sporangiophore branching was distinctly monopodial. Smaller sporangiophore branches were arranged at right angles to the supporting branches, and tips of branches measured 8 to 14 μm long. Sporangia were ovoid and hyaline with a single pore on the distal ends. Distal ends of sporangia were predominantly flat but occasionally had a slight papilla. Short pedicels were present on the attached ends. Sporangia measured 19.4 to 22.2 (-25.0) μm × 13.9 to 16.7 (-19.4) μm. Oospores were not observed in leaf tissue. On the basis of symptoms and morphology of the organism, the pathogen was identified as Plasmopara obducens J. Schröt. Pathogenicity tests were done on double type cvs. Fiesta, Tioga Red, and Tioga Cherry Red and on single type cvs. Cajun Watermelon and Accent Lilac. Plants were spray inoculated with sporangiospore suspensions (1 × 104 sporangiospores per milliliter), incubated for 24 h in a dew chamber (18 to 20°C), and then maintained in a greenhouse (22 to 24°C). Symptoms and signs of downy mildew developed after 12 days only on inoculated cv. Fiesta plants, and the pathogen morphology matched that of the originally observed pathogen. Nontreated control plants did not develop downy mildew. To our knowledge, this is the first report of downy mildew on impatiens in California. P. obducens is one of two causal agents of downy mildew of impatiens (2,4). The other pathogen, Bremiella sphaerosperma, has dichotomous sporangiophore branching and causes lesions with well-defined margins (2,4). In the United States, the disease has been recorded in the eastern and northeastern states and in Indiana, Minnesota, Mississippi, Montana, and Wisconsin (3). In Canada, the disease has been recorded in Manitoba and Quebec (1). References: (1) I. L. Conners. An Annotated Index of Plant Diseases in Canada and Fungi Recorded on Plants in Alaska, Canada, and Greenland. Research Branch, Canada Department of Agriculture, Publication 1251, 1967. (2) O. Constantinescu. Mycologia 83:473, 1991. (3) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, 1989. (4) G. W. Wilson. Bull. Torrey Bot. Club 34:387, 1907.


Plant Disease ◽  
1999 ◽  
Vol 83 (12) ◽  
pp. 1177-1177 ◽  
Author(s):  
J. K. Pataky ◽  
W. F. Tracy

Single, dominant resistance genes have been used successfully for the past 15 years to control common rust, caused by Puccinia sorghi, on sweet corn in the United States. Most sweet corn hybrids grown in the Midwest for mid- to late-season processing have Rp resistance, which is expressed as hypersensitive reactions resulting in chlorotic or necrotic flecks with little or no formation of urediniospores. Many, but not all, Rp-resistant sweet corn hybrids carry the gene Rp1D. Biotypes of P. sorghi in North America have been avirulent on plants with the Rp1D gene, except for an isolate collected in Kansas in 1990 (1). In a sweet corn nursery in Urbana, IL, in 1997, small uredinia of P. sorghi occurred on 27 of 79 Rp-resistant sweet corn hybrids that also were infected severely with southern rust caused by P. polysora (2). During August and September 1999, small uredinia or fully susceptible reactions to common rust were observed on several Rp-resistant sweet corn hybrids grown in an area bounded by Mendota, IL, Ripon, WI, and Le Sueur, MN. Southern rust also was prevalent and frequently severe in the area. Isolates of P. sorghi from Rp-resistant corn were collected during September 1999 from Mendota, Rock Falls, and Dekalb, IL; Sun Prairie, Madison, and Ripon, WI; and Rochester, Stanton, and Le Sueur, MN. Ten two-leaved seedlings of one susceptible sweet corn hybrid and five Rp-resistant hybrids, including hybrids known to carry the gene Rp1D, were inoculated in greenhouse trials. Each location (collection) was a separate trial. Inocula were prepared from several uredinia of P. sorghi per location. One set of seedlings also was inoculated with P. polysora. Susceptible reactions (uredinia with urediniospores) were observed on all inoculated seedlings. Uredinia and urediniospores of P. sorghi and P. polysora from seedlings inoculated in the greenhouse were compared directly. All isolates of P. sorghi were confirmed based on 6- to 7-day latent periods, formation of uredinia on both leaf surfaces, and urediniospores that were mostly spherical, cinnamon colored, and moderately echinulate. This is the first widespread occurrence in North America of a biotype of P. sorghi that is virulent on Rp-resistant sweet corn. References: (1) S. H. Hulbert et al. Plant Dis. 75:1130, 1991. (2) J. K. Pataky et al. Purdue Univ. AES Bull. No. 758:99, 1997.


Author(s):  
Gilson Rogério Marcomini ◽  
Marco Tulio Ospina Patino ◽  
Mohammad Jahangir Alam ◽  
Fernando Rodrigues de Amorim

The potato is one of the most widely cultivated horticultural crops in the world. Brazil ranks 21st among the world's largest potato producers, and the United States (US) is the fifth largest producer in the world. This study analyzes and compares the economic, financial aspects of potato production in the Vargem Grande do Sul region, SP (Brazil), and southwestern Idaho (US), seeking to identify which aspects of American production can serve as reference for technical and financial improvement of the Brazilian production. Data from official sources were analyzed using principal components analysis (PCA). Potato producer in Vargem Grande do Sul need learning how to reduce the factors of production costs to have better financial results in your potato production.


Insects ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 399 ◽  
Author(s):  
Runshi Xie ◽  
Bin Wu ◽  
Haijie Dou ◽  
Cuiyu Liu ◽  
Gary W. Knox ◽  
...  

Crapemyrtle bark scale (CMBS; Acanthococcus lagerstroemiae) is an exotic pest species that causes aesthetic and economic damage to crapemyrtles and poses potential threats to other horticultural crops in the United States. Although previous studies reported the infestation of CMBS on several alternative hosts across multiple families in Asia, its potential threats to other documented alternative hosts remain elusive and yet to be confirmed. In this study, feeding preference studies of CMBS were conducted on forty-nine plant species and cultivars in 2016 and 2019, in order to gain insight into the expansion of CMBS distribution in the United States, as well as other regions of the world. The infestations of CMBS were confirmed on apple (Malus domestica), Chaenomeles speciosa, Disopyros rhombifolia, Heimia salicifolia, Lagerstroemia ‘Spiced Plum’, M. angustifolia, and twelve out of thirty-five pomegranate cultivars. However, the levels of CMBS infestation on these test plant hosts in this study is very low compared to Lagerstroemia, and may not cause significant damage. No sign of CMBS infestation was observed on Rubus ‘Arapaho’, R. ‘Navaho’, R. idaeus ‘Dorman Red’, R. fruticosus, B. microphylla var. koreana × B. sempervirens, B. harlandii, or D. virginiana.


2010 ◽  
Vol 3 (3) ◽  
pp. 262-267 ◽  
Author(s):  
Ryan M. Wersal ◽  
John D. Madsen

AbstractParrotfeather is an invasive, aquatic plant in the United States that is native to South America. It has impaired the use of water bodies throughout the United States and is difficult to control, despite using a variety of management techniques. Our objectives were to examine the efficacy of subsurface applications of seven herbicides labeled for aquatic use and to compare those applications to herbicides that can also be applied to emergent foliage. A replicated mesocosm study was conducted in 378-L (100-gal) tanks beginning in August 2007 and repeated during the same period in 2008. The maximum and half-maximum labeled rates of copper chelate, diquat, endothall, fluridone, triclopyr, and carfentrazone-ethyl were applied to the water column in designated mesocosms. The maximum labeled rate for foliar applications of diquat, triclopyr, and 2,4-D were used to compare treatment methods. Six weeks after treatment (WAT), copper, endothall, fluridone, and carfentrazone-ethyl did not achieve 90% control; in fact, control was less than 50% for each herbicide, and therefore, the herbicides were not considered efficacious for controlling parrotfeather. Diquat at all rates and application methods resulted in 70 to 90% biomass reduction. Triclopyr, with both the highest aqueous concentration and foliar application, resulted in an 84 and 86%, respectively, reduction in biomass at 6 WAT. The foliar application of 2,4-D was the only herbicide and application method that resulted in ≥ 90% biomass reduction of parrotfeather. In these studies, regrowth occurred in all tanks regardless of herbicide or treatment method, indicating multiple applications would be necessary to provide longer-term plant control. Future research should identify possible herbicide combinations or timing of applications to maximize treatment efficacy.


2016 ◽  
Vol 17 (4) ◽  
pp. 232-238 ◽  
Author(s):  
Yuba R. Kandel ◽  
Daren S. Mueller ◽  
Chad E. Hart ◽  
Nathan R. C. Bestor ◽  
Carl A. Bradley ◽  
...  

Foliar disease and insect management on soybean (Glycine max L. Merrill) in the North Central region of the United States has been increasingly accomplished through foliar fungicide and insecticide application. Data from research trials conducted in Illinois, Indiana, Iowa, and Nebraska were compiled from 2008 to 2014 to determine the impact of fungicide, insecticide, and fungicide + insecticide applications on soybean yield and profitability. In each state, field experiments occurred each year in two to seven locations. All treatments were applied at the R3 growth stage. Disease and insect pressure were very low in all states and years. A foliar application of fungicide, insecticide, or the combination, increased yield in seven out of 14 total site-years (P < 0.10). Economic analysis using an average soybean price of $0.42 per kilogram and average application cost of $62 per hectare indicated that fungicide applications were only profitable in 14% of the trial site-years. Insecticide alone and fungicide + insecticide was profitable in 39% and 45% of site-years, respectively. Effect of fungicide class on yield was inconsistent. Our results indicate that although yield increases can occur with foliar fungicide and/or insecticide treatments, current market prices and application costs may limit profitability when disease and/or insect pressure is low. Accepted for publication 22 September 2016.


HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 1016C-1016
Author(s):  
Marcelino Bazán Tene ◽  
Javier Farías Larios ◽  
José Gerardo López Aguirre ◽  
Francisco Radillo Juárez ◽  
Jorge Rogelio Flores Sánchez

Production of horticultural crops is important throughout the world, with high consumption mainly in Europe and the United States of America. Cucumber is consumed both fresh and processed. This vegetable generates important profits for producing countries such as Mexico, which, in 2003, produced 435,897 tons of fresh fruit with a value of 1.190 million Mexican pesos (around USD $109 million). The objective of this work was to evaluate the effect of the floating cover on the yield of fresh cucumbers. Four treatments and five repetitions were imposed in a randomized distribution: covered 20 days (C20) post-emergence, covered until beginning of flowering (CF), covered until beginning of harvest (CIC), and without cover (SC). Data at the first and fourth harvest were analyzed. Results showed that, in the first harvest, treatment C20 days was highest in fruit yield (3.11 ton/ha); Treatment CIC had 2.47 ton/ha, and SC produced 1.66 ton/ha. Data obtained in the fourth harvest, treatment C20, had the highest yield, with 24.12 ton/ha, and treatment CF had a yield of 21.11 ton/ha, but there was not significant difference (Tukey's P < 0.05).


1995 ◽  
Vol 120 (1) ◽  
pp. 112-118 ◽  
Author(s):  
Pedro Revilla ◽  
W.F. Tracy

Sweet corn is one of the most important vegetable crops in the United States, however the morphology and phylogeny of open-pollinated sweet corn cultivars has not been studied. Fifty eight open-pollinated sweet corn cultivars were characterized with thirty-four descriptors to provide information for breeders interested in broadening the genetic base of sweet corn. Principal component analysis and cluster analysis were performed to classify sweet corn cultivars based on morphology. Also, relationships among morphological variables in this set of cultivars were determined. The general ordination of cultivars followed an axis representing earliness, and plant, leaf, and tassel size, while ear and kernel attributes were less variable. The morphological variability among all of the widely used sweet corn cultivars, except `Country Gentleman', was not greater than the variability found among the `Golden Bantam' strains. Based on morphology, 52 of the cultivars could be considered as one race, which we propose be called `Northeastern Sweets'. These may be a subset of the race `Northern Flint'. Five of the remaining cultivars are from the north-central or southwestern United States and may represent races from those areas. The sixth cultivar is `Country Gentleman', a commercially important sweet corn cultivar. Due to the importance of `Country Gentleman' and the introgression of nonsweet germplasm into modern sweet corn, we believe that sweet corn should be defined based on its use as a vegetable and on the presence of one or more genes that increase sugar levels in the endosperm.


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