scholarly journals 003 Epidemiology and Control of Pepper Stip

HortScience ◽  
1999 ◽  
Vol 34 (3) ◽  
pp. 441B-441
Author(s):  
Richard Smith ◽  
Robert Mullen ◽  
Tim Hartz
Keyword(s):  
Total Nitrogen ◽  
Mineral Nutrition ◽  
No Reduction ◽  
Nitrogen Nutrition ◽  
Field Studies ◽  
Nitrogen Application ◽  
Physiological Disorder ◽  
Resistant Cultivars ◽  
Application Rates ◽  
And Control

Pepper stip is a physiological disorder manifested as gray-brown to greenish spots occurring on the fruit of bell, pimento, Anaheim, and other types of peppers, most noticeably on red fruit that mature under fall conditions. Most hybrid bell cultivars are resistant to the malady; the problem is most severe for pepper growers reliant on less-expensive, open-pollinated cultivars. In 1995, we initiated studies to evaluate the possible link between mineral nutrition and this disorder. Two susceptible open-pollinated cultivars and two resistant hybrid cultivars were grown in randomized plots at seven sites. Significant correlations were seen between the levels of potassium (r = 0.59) and calcium (r = -0.37) in whole leaves and the incidence of stip (P = 0.05). The stip-resistant cultivars also maintained less total nitrogen in the whole leaves than susceptible cultivars (P = 0.05). In 1996 and 1997, we undertook field studies to evaluate the effects of varying calcium and nitrogen application rates. Inconsistent results were observed with calcium applications. Moderate reductions in stip incidence was observed at some sites and no reduction at others following foliar calcium applications. Nitrogen nutrition had no effect on stip severity. In 1998, evaluation of a large number of open-pollinated cultivars was undertaken; `Gusto' showed excellent tolerance to pepper stip, followed by `Taurus' and `Cal Wonder 300'. We conclude that growers that are reliant on open-pollinated cultivars can utilize these cultivars to minimize the incidence of pepper stip.

The effect of potassium carbonate solution on the drying of lucerne: 2. Field studies

1978 ◽  
Vol 91 (3) ◽  
pp. 557-561 ◽  
Author(s):  
J. N. Tullberg ◽  
D. J. Minson
Keyword(s):  
Potassium Carbonate ◽  
Dry Matter ◽  
Field Studies ◽  
Carbonate Solution ◽  
Field Exposure ◽  
Moisture Contents ◽  
Application Rates ◽  
Drying Rates ◽  
And Control ◽  
Potassium Carbonate Solution

SummaryIn two field studies it was found that lucerne hay swaths sprayed with 3000 1/ha of 2% (w/w) aqueous potassium carbonate solution after cutting dried more rapidly than mechanically conditioned or control swaths; the ratio of drying rates being 2·17:1·43:1·00 respectively. Hay yields were increased in one of the two studies by the use of potassium carbonate.The effect of different application rates was studied in a third trial using 200, 500 and 875 1/ha potassium carbonate solution, compared with mechanically conditioned and control swaths. After only 29 h of field exposure all swaths treated with potassium carbonate had dried to moisture contents below that required for baling (moisture: dry matter ratio < 0·3).

The effect of benomyl on Gloeotinia temulenta under laboratory and field conditions

1971 ◽  
Vol 11 (53) ◽  
pp. 693 ◽  
Author(s):  
DC McGee
Keyword(s):  
Lolium Perenne ◽  
No Reduction ◽  
Field Studies ◽  
Field Conditions ◽  
Seed Infection ◽  
Laboratory Studies ◽  
Causal Organism ◽  
Infected Seed ◽  
Application Rates ◽  
Seed Crops

Laboratory studies confirmed that benomyl can completely suppress apothecial formation of Gloeotinia temulenta, the causal organism of blind seed disease in grasses. Field studies in Lolium perenne seed crops showed that benomyl, applied at 2.80 and 5.60 kg/hectare, reduced the numbers of apothecia formed by 80 and 90 per cent respectively, while no reduction was apparent at 0.56 kg/hectare. Better results were obtained when the compound was applied in November, just before flowering, than when applied in September or October. At the application rates used, benomyl did not protect plants against seed infection. However, the degree of suppression of apothecial formation possible with benomyl suggests that, in areas where reinfestation of fields with infected seed after harvest is light, the compound should control blind seed disease by limiting formation of apothecia, which are the source of ascospore inoculum, to insignificant proportions.

Studies on White Yam (Dioscorea rotundata) III. Foliar Analysis for Nitrogen Nutrition

1972 ◽  
Vol 8 (3) ◽  
pp. 271-279 ◽  
Author(s):  
R. A. Sobulo
Keyword(s):  
Total Nitrogen ◽  
Tuber Yield ◽  
Nitrate Nitrogen ◽  
Nitrogen Nutrition ◽  
Correlation Coefficients ◽  
Foliar Analysis ◽  
Nitrogen Application ◽  
Dioscorea Rotundata ◽  
White Yam

SUMMARYThe concentrations of total nitrogen and nitrate–nitrogen in yam leaves receiving various levels of nitrogen were determined fortnightly. Nitrate–nitrogen was superior to total nitrogen as an index of nitrogen nutrition. Correlation coefficients between nitrate–nitrogen at various sampling dates and rate of nitrogen application were highest between late June and early July in two seasons, indicating that this is the best time to take single samples for foliar analysis. A relation was demonstrated between nitrate–nitrogen at this period and tuber yield.

scholarly journals Nitrogen Nutrition of Containerized Anemone x hybrida

2000 ◽  
Vol 18 (3) ◽  
pp. 145-148
Author(s):  
Jean-Jacques B. Dubois ◽  
Stuart L. Warren ◽  
Frank A. Blazich
Keyword(s):  
Leaf Area ◽  
Nitrogen Nutrition ◽  
Dry Weight ◽  
Nitrogen Application ◽  
Constant Ratio ◽  
Application Rates ◽  
Single Crown ◽  
Top Dry Weight ◽  
Complete Nutrient Solution ◽  
Propagation Material

Abstract Uniform single crown plantlets of Anemone x hybrida Paxton ‘Margarete’ were grown in 3.8-liter (#1) containers filled with a substrate of composted pine bark:sand (8:1 by vol). Plants were fertilized three times weekly for 15 weeks with a complete nutrient solution at nitrogen application rates (NARs) of 10, 40, 80, 150 or 300 mg/liter (ppm) nitrogen (N), in a constant ratio of 1 ammonium:2 nitrate. All other nutrients were held constant. Leaf area, top dry weight, and root dry weight increased with increasing NAR until reaching a plateau at a NAR of 144 ± 21 mg/liter (ppm), 158 ± 28 mg/liter (ppm), and 119 ± 30 mg/liter (ppm), respectively. The proportion of fine roots to thick roots was unaffected, and production of propagation material (root cuttings) reached a plateau at a NAR of 108 ± 28 mg/liter (ppm). Leaf concentrations of N, P, and K at maximum leaf area were 4.7%, 0.5%, and 3.5%, respectively.

scholarly journals Structural characteristics of marandu palisadegrass swards subjected to continuous stocking and contrasting rhythms of growth

2010 ◽  
Vol 67 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Priscila de Mesquita ◽  
Sila Carneiro da Silva ◽  
Adenilson José Paiva ◽  
Fábio Olegário Caminha ◽  
Lilian Elgalise Techio Pereira ◽  
...  
Keyword(s):  
Structural Characteristics ◽  
Light Interception ◽  
Grazing Management ◽  
Nitrogen Application ◽  
Area Index ◽  
Application Rates ◽  
Wide Range ◽  
And Control ◽  
Sward Structure ◽  
Monitor And Control

The concept of sward target has been used recently to characterise grazing management practices, but its efficiency to monitor and control sward structure questioned since it corresponds to a single sward structural feature, usually sward surface height. The objective of this experiment was to evaluate sward structure and its patterns of variation throughout the year on continuously stocked marandu palisadegrass swards maintained at 30 cm and subjected to contrasting rhythms of growth from January 2007 to April 2008. Treatments corresponded to three nitrogen application rates (150, 300 and 450 kg ha-1 of N) plus the control (no N fertilisation), and were allocated to experimental units according to a complete randomised block design, with four replications. Sward herbage mass, morphological composition, leaf area index (LAI), foliage angle and light interception were evaluated. The increase in nitrogen application rates resulted in increased sward herbage mass, proportion of leaf and stem, and reduction in the proportion of dead material. These modifications were in line with the increase in LAI and reduction in foliage angle, although they did not modify sward light interception. Despite the wide range of nitrogen application rates used, there was a common pattern of variation in sward structure. Overall, changes in sward structural characteristics generated by the range of growth rhythms studied were small, indicating that sward height corresponded to an efficient way to monitor and control the grazing process and sward structure, and can be used to define targets of grazing management.

scholarly journals 111 Metsulfuron and variable nitrogen application rates on infected tall fescue: effects on stocker performance, forage yield, nutritive value, ergovaline concentration and botanical composition

2020 ◽  
Vol 98 (Supplement_2) ◽  
pp. 31-31
Author(s):  
Kevin R Meng ◽  
Eric Bailey ◽  
Josh Zeltwanger ◽  
Hannah Allen ◽  
Mikaela Adams ◽  
...  
Keyword(s):  
Species Composition ◽  
Tall Fescue ◽  
Nutritive Value ◽  
Ergot Alkaloids ◽  
Fertilization Rate ◽  
Forage Yield ◽  
Nitrogen Application ◽  
Forage Production ◽  
Seed Head ◽  
Application Rates

Abstract Chemical seed-head suppression of endophyte infected tall fescue (Lolium arundinaceum) improves stocker cattle performance but may decrease forage yield. Spring nitrogen application increases tall fescue growth with a concomitant increase in ergot alkaloids, produced by the symbiotic endophyte Epichloë coenophiala. We hypothesized that greater amounts of nitrogen applied to tall fescue would increase forage yield and offset losses in forage production from chemical suppression of seed-heads with metsulfuron without effect on alkaloid concentration. Ninety-six steers (270 ± 20 kg) were randomly assigned to one of sixteen paddocks (1.8 ha) on April 18 and continuously grazed for 57 d. Paddocks were blocked by previous use (n = 4) and randomly assigned to one of four treatments; no metsulfuron, no nitrogen (NEGCON), metsulfuron with 0 (MET0), 67 (MET67), or 134 (MET134) kg/ha of ammonium nitrate, applied March 11. Steers grazing MET0 paddocks were removed 17 d early due to insufficient forage availability. Steer weight, forage yield, forage nutritive value and ergot alkaloids in forage samples were measured monthly. Seed-head frequency and species composition were determined in June. Metsulfuron application reduced (P &lt; 0.01) tall fescue seed-heads by 80%. Metsulfuron decreased (P = 0.03) ergovaline but ergovaline increased (P &lt; 0.01) at each monthly sampling across treatments. Nitrogen had no impact on ergovaline concentration (P = 0.50). Forage yield tended to be least (P = 0.07) for MET0, intermediate for NEGCON and MET67, and tended to be greatest for MET134 (P = 0.08). Steer ADG was not affected by treatment (P &lt; 0.80). Metsulfuron decreased NDF (P=0.02) regardless of fertilization rate. Forage CP increased with fertilization (P &lt; 0.01) and no differences were detected between NEGCON and MET0 (P = 0.45). Species composition was not impacted (P &gt;0.07) by treatment. Metsulfuron decreased seed-head growth and ergovaline concentration in tall fescue. Additional nitrogen fertilizer ameliorated forage yield lost to metsulfuron application but did not impact steer gain.

Evaluation of weed control in acetyl coA carboxylase-resistant rice with mixtures of quizalofop and auxinic herbicides

2019 ◽  
Vol 34 (4) ◽  
pp. 498-505
Author(s):  
Tameka L. Sanders ◽  
Jason A. Bond ◽  
Benjamin H. Lawrence ◽  
Bobby R. Golden ◽  
Thomas W. Allen ◽  
...  
Keyword(s):  
Weed Control ◽  
Rice Yield ◽  
Field Studies ◽  
Growth Stages ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Herbicide Treatments ◽  
Herbicide Mixture ◽  
Sequential Treatments ◽  
And Control

AbstractRice with enhanced tolerance to herbicides that inhibit acetyl coA carboxylase (ACCase) allows POST application of quizalofop, an ACCase-inhibiting herbicide. Two concurrent field studies were conducted in 2017 and 2018 near Stoneville, MS, to evaluate control of grass (Grass Study) and broadleaf (Broadleaf Study) weeds with sequential applications of quizalofop alone and in mixtures with auxinic herbicides applied in the first or second application. Sequential treatments of quizalofop were applied at 119 g ai ha−1 alone and in mixtures with labeled rates of auxinic herbicides to rice at the two- to three-leaf (EPOST) or four-leaf to one-tiller (LPOST) growth stages. In the Grass Study, no differences in rice injury or control of volunteer rice (‘CL151’ and ‘Rex’) were detected 14 and 28 d after last application (DA-LPOST). Barnyardgrass control at 14 and 28 DA-LPOST with quizalofop applied alone or with auxinic herbicides EPOST was ≥93% for all auxinic herbicide treatments except penoxsulam plus triclopyr. Barnyardgrass control was ≥96% with quizalofop applied alone and with auxinic herbicides LPOST. In the Broadleaf Study, quizalofop plus florpyrauxifen-benzyl controlled more Palmer amaranth 14 DA-LPOST than other mixtures with auxinic herbicides, and control with this treatment was greater EPOST compared with LPOST. Hemp sesbania control 14 DA-LPOST was ≤90% with quizalofop plus quinclorac LPOST, orthosulfamuron plus quinclorac LPOST, and triclopyr EPOST or LPOST. All mixtures except quinclorac and orthosulfamuron plus quinclorac LPOST controlled ivyleaf morningglory ≥91% 14 DA-LPOST. Florpyrauxifen-benzyl or triclopyr were required for volunteer soybean control >63% 14 DA-LPOST. To optimize barnyardgrass control and rice yield, penoxsulam plus triclopyr and orthosulfamuron plus quinclorac should not be mixed with quizalofop. Quizalofop mixtures with auxinic herbicides are safe and effective for controlling barnyardgrass, volunteer rice, and broadleaf weeds in ACCase-resistant rice, and the choice of herbicide mixture could be adjusted based on weed spectrum in the treated field.

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