Response of processing carrot to metribuzin on mineral soils in Nova Scotia

2004 ◽  
Vol 84 (2) ◽  
pp. 669-676 ◽  
Author(s):  
K. I. N. Jensen ◽  
D. J. Doohan ◽  
E. G. Specht
Keyword(s):  
Nova Scotia ◽  
Soil Ph ◽  
Field Studies ◽  
The United States ◽  
Controlled Environment ◽  
Ph Effects ◽  
Stellaria Media ◽  
Daucus Carota L ◽  
Leaf Stage ◽  
Mineral Soils

Metribuzin was examined as an alternative to linuron and prometryn when prometryn-treated processed carrot in Atlantic Canada in the 1990s could not be exported to the United States, where prometryn was not registered for this crop. Field studies demonstrated that 280 g ha-1 metribuzin applied after the three-leaf crop stage resulted in only minor injury and no yield loss for both a metribuzin-tolerant (Caro-Choice) and -sensitive (Dominator) cultivar. Metribuzin applied either pre- or post-emergence controlled two Matricaria species, chickweed [Stellaria media (L.) Vill.] and shepherd’s-purse [Capsella bursa-pastoris (L.) Medik.], equivalent to approved prometryn and linuron treatments. Controlled environment studies were conducted to examine the effect of crop growth stage, temperature and soil pH on metribuzin injury to carrot. Differential tolerance between the two cultivars occurred only up to the three-leaf stage. Under controlled environment conditions, carrot injury to metribuzin increased threefold as soil pH increased from 6.5 to 7.4. There was little injury when metribuzin was applied postemergence under cool temperatures (15/10°C), but injury increased from 25 to 85% under 20/15°C and 30/25°C regimes. Lower temperatures and naturally low pH soils contribute to carrot tolerance to metribuzin under Nova Scotia conditions. Based on this research, metribuzin at 280 g ha-1 applied after the three-leaf stage of carrot was approved for use in the Atlantic provinces. Key words: Daucus carota L., cultivar tolerance, soil pH effects, temperature effects, weed control

Effect of Sugarcane Cultivar and Foliar Insecticide Treatment on Infestations of the Invasive Sugarcane Thrips, Fulmekiola serrata (Thysanoptera: Thripidae), in Florida

2019 ◽  
Vol 112 (6) ◽  
pp. 2703-2712 ◽  
Author(s):  
J M Beuzelin ◽  
M T VanWeelden ◽  
F N Soto-Adames ◽  
H S Sandhu ◽  
R W Davidson ◽  
...  
Keyword(s):  
Field Studies ◽  
The United States ◽  
Organic Soils ◽  
Insecticide Treatment ◽  
Sugarcane Cultivar ◽  
Lambda Cyhalothrin ◽  
Production Area ◽  
Mineral Soils ◽  
Management Recommendations ◽  
First Time

Abstract Fulmekiola serrata (Kobus) was observed infesting sugarcane, Saccharum spp. hybrids, in the United States for the first time in January 2017 in Florida. Field studies were conducted to determine F. serrata infestation levels on popular sugarcane cultivars and to determine the efficacy of foliar insecticide treatments that could be used for management. Cultivar evaluations comparing six and five commercial cultivars representing >46% of the sugarcane production area in Florida were conducted in 2017 and 2018, respectively. Fulmekiola serrata infestation levels did not differ among cultivars in 2017. However, infestation levels on CP 00-1101 were greater than on CP 96-1252 grown on organic soils, and infestation levels on CP 96-1252 were greater than on CPCL 97-2730 grown on mineral soils in 2018. Three insecticide evaluations, two in 2017 and one in 2018, were conducted. The pyrethroid lambda-cyhalothrin, which is registered for use on sugarcane, was consistently associated with the greatest decreases in F. serrata infestation levels. The neonicotinoids imidacloprid and thiamethoxam, as well as the butenolide flupyradifurone, decreased infestation levels but to a lesser extent than did lambda-cyhalothrin. The spinosyn spinetoram was associated with the lowest decreases in F. serrata infestation levels. Our results supported short-term F. serrata management recommendations: Popular Florida sugarcane cultivars should be considered equally susceptible to F. serrata until additional evaluations are conducted and F. serrata outbreaks can be treated with lambda-cyhalothrin when infestations stress the crop beyond acceptable levels.

scholarly journals Assessing the geographic specificity of pH prediction by classification and regression trees

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0255119
Author(s):  
Jacob Egelberg ◽  
Nina Pena ◽  
Rachel Rivera ◽  
Christina Andruk
Keyword(s):  
Random Forest ◽  
Soil Ph ◽  
Predictive Accuracy ◽  
Regression Trees ◽  
The United States ◽  
Classification And Regression Trees ◽  
Previous Literature ◽  
Ph Effects ◽  
Wide Range ◽  
Classification And Regression

Soil pH effects a wide range of critical biogeochemical processes that dictate plant growth and diversity. Previous literature has established the capacity of classification and regression trees (CARTs) to predict soil pH, but limitations of CARTs in this context have not been fully explored. The current study collected soil pH, climatic, and topographic data from 100 locations across New York’s Temperate Deciduous Forests (in the United States of America) to investigate the extrapolative capacity of a previously developed CART model as compared to novel CART and random forest (RF) models. Results showed that the previously developed CART underperformed in terms of predictive accuracy (RRMSE = 14.52%) when compared to a novel tree (RRMSE = 9.33%), and that a novel random forest outperformed both models (RRMSE = 8.88%), though its predictions did not differ significantly from the novel tree (p = 0.26). The most important predictors for model construction were climatic factors. These findings confirm existing reports that CART models are constrained by the spatial autocorrelation of geographic data and encourage the restricted application of relevant machine learning models to regions from which training data was collected. They also contradict previous literature implying that random forests should meaningfully boost the predictive accuracy of CARTs in the context of soil pH.

Use of Biomonitoring to Control Toxics in the United States

1988 ◽  
Vol 20 (10) ◽  
pp. 101-108 ◽  
Author(s):  
Nelson A. Thomas
Keyword(s):  
Water Quality ◽  
Chronic Toxicity ◽  
National Policy ◽  
Single Species ◽  
Field Studies ◽  
The United States ◽  
Toxicity Tests ◽  
Toxic Pollutants ◽  
Receiving Waters ◽  
Biological Field

A biomonitoring program has been developed in support of the National Policy for the Development of Water Quality-Based Permit Limitations for Toxic Pollutants. The program focuses on the use of laboratory toxicity tests on aquatic plants and animals to predict ecosystem impact caused by toxic pollutants. Both acute and chronic toxicity tests were developed to test effluents and ambient waters. Laboratory and biological field studies were conducted at nine sites. Single species laboratory toxicity tests were found to be good predictors of impacts on the ecosystem when two or more species were used. Biomonitoring can be undertaken either on effluents and/or on the receiving waters. In that toxicity related to seeps, leachates and storm sewers has often been found upstream from dischargers, it is beneficial to conduct both effluent and ambient biomonitoring.

Do fungi and bacteria respond similar across a steep local pH gradient?

2021 ◽  
Author(s):  
Rasmus Kjoller ◽  
Carla Cruz-Paredes
Keyword(s):  
Community Composition ◽  
Soil Ph ◽  
Wood Ash ◽  
Ph Gradient ◽  
Fungal Communities ◽  
Ph Effects ◽  
Fungal Community Composition ◽  
Ph Gradients ◽  
Field Samples ◽  
Bacterial Richness

<p>Soil pH is consistently recorded as the single most important variable explaining bacterial richness and community composition locally as globally. Bacterial richness responds to soil pH in a bell-shaped pattern, highest in soils with near-neutral pH, while lower diversity is found in soil with pH >8 and <4.5. Also, community turnover is strongly determined by pH for bacteria. In contrast, pH effects on fungi is apparently less pronounced though also much less studied compared to bacteria. Still, pH appears to be a significant determinant for fungal communities but typically not the most important. Rarely are bacterial and fungal communities co-analyzed from the same field samples taken across pH gradients. Here we analyze the community responses of fungi and bacteria in parallel over an extreme pH gradient ranging from pH 4 to 8 established by applying strongly alkaline wood ash to replicated plots in a Picea abies plantation. Bacterial and fungal community composition were assessed by amplicon-based meta-barcoding. Bacterial richness were not significantly affected by pH, while fungal richness and a-diversity were stimulated with higher pH. We found that both, bacterial and fungal communities increasingly deviated from the untreated plots with increasing amount of wood ash though fungal communities were more resistant to changes than bacterial. Soil NH<sub>4</sub>, NO<sub>3</sub> and pH significantly correlated with the NMDS pattern for both bacterial and fungal communities. In the presentation we will discuss resistance versus sensitivity of different fungal functional guilds towards higher pH as well as the underlying factors explaining the community changes.</p>

scholarly journals An updated understanding of Texas bumble bee (Hymenoptera: Apidae) species presence and potential distributions in Texas, USA

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3612 ◽  
Author(s):  
Jessica L. Beckham ◽  
Samuel Atkinson
Keyword(s):  
Citizen Science ◽  
Species Distributions ◽  
Field Studies ◽  
The United States ◽  
Bumble Bee ◽  
Suitable Habitat ◽  
Distribution Models ◽  
Species List ◽  
Central Texas ◽  
Declining Species

Texas is the second largest state in the United States of America, and the largest state in the contiguous USA at nearly 700,000 sq. km. Several Texas bumble bee species have shown evidence of declines in portions of their continental ranges, and conservation initiatives targeting these species will be most effective if species distributions are well established. To date, statewide bumble bee distributions for Texas have been inferred primarily from specimen records housed in natural history collections. To improve upon these maps, and help inform conservation decisions, this research aimed to (1) update existing Texas bumble bee presence databases to include recent (2007–2016) data from citizen science repositories and targeted field studies, (2) model statewide species distributions of the most common bumble bee species in Texas using MaxEnt, and (3) identify conservation target areas for the state that are most likely to contain habitat suitable for multiple declining species. The resulting Texas bumble bee database is comprised of 3,580 records, to include previously compiled museum records dating from 1897, recent field survey data, and vetted records from citizen science repositories. These data yielded an updated state species list that includes 11 species, as well as species distribution models (SDMs) for the most common Texas bumble bee species, including two that have shown evidence of range-wide declines: B. fraternus (Smith, 1854) and B. pensylvanicus (DeGeer, 1773). Based on analyses of these models, we have identified conservation priority areas within the Texas Cross Timbers, Texas Blackland Prairies, and East Central Texas Plains ecoregions where suitable habitat for both B. fraternus and B. pensylvanicus are highly likely to co-occur.

scholarly journals Integrated Control of Rhizoctonia Crown and Root Rot of Sugar Beet with Fungicides and Antagonistic Bacteria

Plant Disease ◽  
2001 ◽  
Vol 85 (7) ◽  
pp. 718-722 ◽  
Author(s):  
Sebastian Kiewnick ◽  
Barry J. Jacobsen ◽  
Andrea Braun-Kiewnick ◽  
Joyce L. A. Eckhoff ◽  
Jerry W. Bergman
Keyword(s):  
Sugar Beet ◽  
Root Rot ◽  
Integrated Control ◽  
The United States ◽  
Field Trials ◽  
Sugar Yield ◽  
Economic Losses ◽  
Yield Increase ◽  
Leaf Stage ◽  
Crown And Root Rot

Rhizoctonia crown and root rot, caused by the fungus Rhizoctonia solani AG 2-2, is one of the most damaging sugar beet diseases worldwide and causes significant economic losses in more than 25% of the sugar beet production area in the United States. We report on field trials in the years 1996 to 1999 testing both experimental fungicides and antagonistic Bacillus sp. for their potential to reduce disease severity and increase sugar yield in trials inoculated with R. solani AG 2-2. Fungicides were applied as in-furrow sprays at planting or as band sprays directed at the crown at the four-leaf stage, or four- plus eight-leaf stage, while bacteria were applied at the four-leaf stage only. The fungicides azoxystrobin and tebuconazole reduced crown and root rot disease by 50 to 90% over 3 years when used at rates of 76 to 304 g a.i./ha and 250 g a.i./ha, respectively. The disease index at harvest was reduced and the root and sugar yield increased with azoxystrobin compared with tebuconazole. The combination of azoxystrobin applied at 76 g a.i./ha and the Bacillus isolate MSU-127 resulted in best disease reduction and greatest root and sucrose yield increase.

scholarly journals Ergonomic Evaluation of Current Advancements in Blueberry Harvesting

Agronomy ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 266 ◽  
Author(s):  
Eunsik Kim ◽  
Andris Freivalds ◽  
Fumiomi Takeda ◽  
Changying Li
Keyword(s):  
Occupational Safety ◽  
Health And Safety ◽  
Field Studies ◽  
The United States ◽  
Epidemiological Studies ◽  
Component Ratio ◽  
Social Scientists ◽  
Private Industry ◽  
Work Related ◽  
Trauma Disorders

Work-related musculoskeletal disorders (MSDs) accounted for 32% of days-away-from-work cases in private industry in 2016. Several factors have been associated with MSDs, such as repetitive motion, excessive force, awkward and/or sustained postures, and prolonged sitting and standing, all of which are required in farm workers’ labor. While numerous epidemiological studies on the prevention of MSDs in agriculture have been conducted, an ergonomics evaluation of blueberry harvesting has not yet been systematically performed. The purpose of this study was to investigate the risk factors of MSDs for several types of blueberry harvesting (hand harvesting, semi-mechanical harvesting with hand-held shakers, and over-the-row machines) in terms of workers’ postural loads and self-reported discomfort using ergonomics intervention techniques. Five field studies in the western region of the United States between 2017 and 2018 were conducted using the Borg CR10 scale, electromyography (EMG), Rapid Upper Limb Assessment (RULA), the Cumulative Trauma Disorders (CTD) index, and the NIOSH (National Institute for Occupational Safety and Health) lifting equation. In evaluating the workloads of picking and moving blueberries by hand, semi-mechanical harvesting with hand-held shakers, and completely mechanized harvesting, only EMG and the NIOSH lifting equation were used, as labor for this system is limited to loading empty lugs and unloading full lugs. Based on the results, we conclude that working on the fully mechanized harvester would be the best approach to minimizing worker loading and fatigue. This is because the total component ratio of postures in hand harvesting with a RULA score equal to or greater than 5 was 69%, indicating that more than half of the postures were high risk for shoulder pain. For the semi-mechanical harvesting, the biggest problem with the shakers is the vibration, which can cause fatigue and various risks to workers, especially in the upper limbs. However, it would be challenging for small- and medium-sized blueberry farms to purchase automated harvesters due to their high cost. Thus, collaborative efforts among health and safety professionals, engineers, social scientists, and ergonomists are needed to provide effective ergonomic interventions.

scholarly journals Efficacy of a novel topical combination of esafoxolaner, eprinomectin and praziquantel against fleas in cats, under field conditions

Parasite ◽  
2021 ◽  
Vol 28 ◽  
pp. 22 ◽  
Author(s):  
Eric Tielemans ◽  
Tomoko Otsuki ◽  
Tara Cheesman ◽  
Fiona Selmes ◽  
Anthony Pfefferkorn ◽  
...  
Keyword(s):  
United States ◽  
Field Studies ◽  
The United States ◽  
Positive Control ◽  
Control Group ◽  
The Novel ◽  
Domestic Cats ◽  
Label Dose ◽  
Treatment Tolerance ◽  
Significant Health

Esafoxolaner is a purified afoxolaner enantiomer with insecticidal and acaricidal properties. It is combined with eprinomectin and praziquantel, nematodicidal and cestodicidal compounds, in a novel topical endectoparasiticide formulation for cats. This novel formulation was tested in four field studies, in the United States, Europe, Japan and Australia. In all studies, naturally flea-infested domestic cats were treated with the novel formulation at the label dose and conditions of use. The main objective, identical in the four studies, was to assess efficacy on fleas, based on comparison of mean number of fleas found on infested cats before and one month after treatment. Tolerance to the product was also evaluated in the four studies. Otherwise, the studies had some differences in their design and secondary objectives, for example testing for a reduction in flea infestation-related cutaneous signs, testing of one treatment or of three monthly treatments, and use of a positive control group. In the four studies, a total of 307 cats were treated with the novel formulation. The reduction of fleas one month after treatment was 97.7%, 98.8%, 100% and 99.7% in the United States, Europe, Japan and Australia, respectively. There were no significant health abnormalities attributed to treatment in any of the studies.

Temperature and leaf area expansion of sugarcane: integration of controlled-environment, field and model studies

1998 ◽  
Vol 25 (7) ◽  
pp. 819 ◽  
Author(s):  
Michael J. Robertson ◽  
Graham D. Bonnett ◽  
R. Michael Hughes ◽  
Russell C. Muchow ◽  
James A. Campbell
Keyword(s):  
Leaf Area ◽  
Leaf Senescence ◽  
Leaf Size ◽  
Field Studies ◽  
Growth Conditions ◽  
Thermal Time ◽  
Leaf Position ◽  
Potential Growth ◽  
Leaf Stage ◽  
Leaf Appearance

Canopy development is an important determinant of crop radiation interception, and in the absence of stress is mainly driven by temperature. The responses to temperature of the component processes of canopy dynamics in sugarcane: leaf appearance, leaf size, tillering, and leaf senescence, were analysed for the commercial Australian cultivar, Q117. Data were derived under optimal growth conditions from controlled environments, and from irrigated field studies in subtropical and tropical locations. Regression of number of fully-expanded leaves in field-grown plants against cumulative thermal time revealed that the thermal time between the appearance of successive leaves increased as a function of leaf number, such that leaf 1 required 86˚Cd and leaf 40 required 160˚Cd. At any moment, on average there were 3.7 leaves still expanding on the stalks. Functions describing leaf appearance gave acceptable prediction of the time course of leaf appearance taken from independent datasets of field-grown plant and ratoon crops. Leaf size increased with leaf position, with the largest leaves observed at approximately leaf 17 and above. Combining functions describing leaf appearance and leaf size as a function of leaf position allowed estimation of leaf area index (LAI) of main stems in plant and ratoon crops in subtropical and tropical environments. Tiller LAI, derived by difference, accounted for 60–90% of total LAI at the 5- leaf stage, declining to 20–50% at the 15-leaf stage. Plant and ratoon crops were similar in terms of the amount and proportion of tiller LAI. Combining data from all field studies indicated under potential growth conditions, leaf senescence was closely related to leaf production. The functions derived in this study give a basis for simulating canopy dynamics under potential growth conditions in sugarcane, though the extent of genotypic variation for the key parameters and their modification by stress remains to be assessed.

Thermal history and subsidence of rifted continental margins—evidence from wells on the Nova Scotian and Labrador Shelves

1979 ◽  
Vol 16 (3) ◽  
pp. 505-522 ◽  
Author(s):  
C. E. Keen
Keyword(s):  
Nova Scotia ◽  
Time History ◽  
The United States ◽  
Tectonic Subsidence ◽  
Continental Margins ◽  
Thermal Cooling ◽  
Nova Scotian ◽  
Temperature Time ◽  
Good Agreement ◽  
Cooling Model

The subsidence histories of the Labrador and Nova Scotian rifted continental margins have been determined from biostratigraphic data for 11 deep exploratory wells off Nova Scotia, for five wells off Labrador, for three wells northeast of Newfoundland, and for one well off the northeast coast of the United States of America. The components of subsidence, due to sediment loading, and when possible due to loading by changes in eustatic sea level, were removed, leaving that part of the subsidence, the tectonic subsidence, caused by cooling of the lithosphere or by other deep seated processes. The thermal cooling model theoretically predicts a linear relationship between tectonic subsidence and t½, where t is the time since subsidence began. This relationship should be obeyed during the first tens of Ma of subsidence. The slope of this curve depends upon the temperature to which the crust and upper mantle were heated during the initial rifting stage and can be used to derive the temperature–time history within the sediments, the present temperature distribution, and geothermal gradient. The data show that the observed subsidence curves behave in accordance with the thermal cooling model, at least during the first 80 Ma after subsidence began and obey the equation y = 300(± 80)t1/2 m, where y is the tectonic subsidence. The slopes of the subsidence curves are similar for the Labrador Shelf, the Nova Scotian Shelf, and the shelf off the northeastern U.S.A. More rapid and variable subsidence occurs northeast of Newfoundland and this may be associated, in a way yet to be established, with the anomalous foundered continental crust near the Orphan Knoll and Flemish Cap micro-continents which lie close to this area. After about 80 Ma, the subsidence appears to depart from the linear t1/2 law in a manner similar to the subsidence curves for oceanic crust, but this is not well established by the data. The present temperatures and temperature gradients computed using the slope of the subsidence curves show good agreement with measured values; geothermal gradients of 17.5 °C km−1 and 26 °C km−1 are calculated off Nova Scotia and Labrador respectively, and mean values of about 23 °C km−1 are observed. The computed temperature–time history within the sediments was used to estimate values of vitrinite reflectance, an indicator of the degree of organic metamorphism. These values show reasonable agreement with the measured values and suggest that only the Upper Jurassic and Lower Cretaceous sediments off Nova Scotia and the Paleocene sediments off Labrador are sufficiently mature to be good sources of petroleum. The linear t1/2 behaviour of the subsidence, and the good agreement between predicted and observed temperatures support the contention that cooling is largely responsible for the observed tectonic subsidence. The similarity of results from different areas suggests that the usefulness of the method is not restricted to a particular geographical area and may be applied to other rifted continental margins. Comparisons between the subsidence rates, thermal histories, and crustal structure at rifted margins on a worldwide scale may provide insights concerning the processes controlling their development. The temperature–time histories of the sediments estimated from the subsidence may be useful in establishing the potential of a rifted margin area for petroleum generation when little other information is available.

Sign in / Sign up

Export Citation Format

Share Document