SAWFLY RESISTANCE IN WHEAT: III. CHANGES IN RESISTANCE DURING THE DEVELOPMENT OF THE WHEAT PLANT

1960 ◽  
Vol 40 (1) ◽  
pp. 7-20 ◽  
Author(s):  
D. W. A. Roberts
Keyword(s):  
Quantitative Data ◽  
Field Experiments ◽  
Wheat Plant ◽  
Flowering Stage ◽  
Wheat Stem Sawfly ◽  
Cephus Cinctus ◽  
Stage Of Development ◽  
First Instar ◽  
Golden Ball

Quantitative data obtained in field experiments showed that the resistance of wheat to attack by the wheat stem sawfly (Cephus cinctus Nort.) depended on the stage of development of the plants at the time of oviposition. Wheat plants were usually most heavily infested for a part or all of the period from 1 week before shot blade to 1 week after the flowering stage. Rescue, H46146, H4191, Golden Ball, and Melanopus lost their resistance to the development of the eggs and first-instar larvae some time between shot blade and flowering. Thatcher and Red Bobs did not show this type of resistance. The mortality of the older larvae increased in plants infested toward maturity. The time at which this increase began depended on the variety involved and ranged from just before shot blade to just after flowering.

SAWFLY RESISTANCE IN WHEAT: II. DIFFERENCES BETWEEN WHEAT GROWN IN THE GREENHOUSE AND ON IRRIGATED LAND

1957 ◽  
Vol 37 (3) ◽  
pp. 292-299 ◽  
Author(s):  
D. W. A. Roberts
Keyword(s):  
The Other ◽  
Dry Land ◽  
Wheat Stem Sawfly ◽  
Cephus Cinctus ◽  
Variable Resistance ◽  
Lower Resistance ◽  
Stem Solidness ◽  
Golden Ball

The resistance of seven varieties of wheat to the wheat stem sawfly (Cephus cinctus Nort.) was tested in the greenhouse and on irrigated plots. In five of the seven varieties tested, namely, Rescue, H46146, Golden Ball, Red Bobs and Thatcher, the percentage of infested stems that were cut by sawflies was significantly higher in plants grown in the greenhouse in either summer or winter than in plants grown under irrigation in the field. In the other two varieties, H4191 and Melanopus, results were similar but the differences were not significant. This lower resistance of plants grown in the greenhouse was associated with a decrease in the percentage of tunnelled stems in which the older larvae had died. In percentage of infested stems cut, no significant differences were found between the varieties grown in the outdoor soil bins and those on adjacent irrigated land. In other 2-year tests on irrigated land, the variable resistance of wheat was apparently associated with variations in percentage of tunnelled stems in which the older larvae had died. Although stem solidness is usually associated with resistance on dry land, it appears that this characteristic alone cannot be relied on as a measure of sawfly resistance in a given variety when grown in diverse environments.

Differences in Survival of the Wheat Stem Sawfly, Cephus cinctus Nort. (Hymenoptera: Cephidae), from Two Geographic Areas in Varieties of Spring Wheat

1957 ◽  
Vol 89 (6) ◽  
pp. 272-275 ◽  
Author(s):  
N. D. Holmes ◽  
L. K. Peterson ◽  
A. J. McGinnis
Keyword(s):  
Spring Wheat ◽  
Late Summer ◽  
Ground Level ◽  
Genetic Variations ◽  
Wheat Stem Sawfly ◽  
Cephus Cinctus ◽  
Below Ground ◽  
Golden Ball

The larva of the wheat stem sawfly, Cephus cinctus Nort., lives inside the host stem, cuts it off at ground level in late summer, and spends the winter inside the stub below ground level. This insect can be controlled by the use of resistant spring wheats such as Rescue and Golden Ball. The possibility of the existence of a strain of C. cinctus to which these varieties are not resistant is of major importance.Platt, Farstad, and Callenbach (1948) found that the average percentages of Rescue stems cut by C. cinctus for five years were 36 at Regina, Saskatchewan, and two at Lethbridge. They suggested that this difference may have resulted from the effects of the environments in two areas, or from genetic variations between the sawflies at the two stations.

Effect of Time of Seeding Apex Wheat on Infestation and Sex Ratio of the Wheat Stem Sawfly, Cephus cinctus Nort. (Hymenoptera: Cephidae)

1952 ◽  
Vol 84 (3) ◽  
pp. 90-92 ◽  
Author(s):  
L. A. Jacobson ◽  
C. W. Farstad
Keyword(s):  
Sex Ratio ◽  
Field Experiment ◽  
Wheat Stem Sawfly ◽  
Cephus Cinctus

In 1945 a field experiment was designed at the Lethbridge laboratory to augment data on the effect of the time of seeding on infestation by the wheat stem sawfly, Cephus cinctus Nort. At that time one of the recommendations for the control of this insect was to delay seeding wheat until after May 15. The resulting crop escaped infestation because of the retarded plant during the period of the sawfly flight.

Survey of Wheat Stem Sawfly (Hymenoptera: Cephidae) Infesting Wheat in Eastern Colorado

2021 ◽  
Author(s):  
Darren M Cockrell ◽  
Terri Randolph ◽  
Erika Peirce ◽  
Frank B Peairs
Keyword(s):  
Triticum Aestivum ◽  
Wheat Variety ◽  
Triticum Aestivum L ◽  
The State ◽  
Economic Effects ◽  
Management Decisions ◽  
Wheat Stem Sawfly ◽  
Cephus Cinctus ◽  
Growing Region

Abstract From 2012 through 2020, a survey of wheat stem sawfly, Cephus cinctus Norton, was conducted in wheat (Triticum aestivum L.) fields in Eastern Colorado. In 2013, results showed sawfly infestations concentrated in the northern part of the state with only a few highly infested sites, with 38 of the 94 sampled sites having any infestation (five of which had >50% infestation levels). By 2020 sawfly had been found in all eastern counties sampled, and 72 of the 106 sites sampled were found to contain sawfly (11 of which had >50% infestation levels). The spread of this pest across the Colorado wheat-growing region will have lasting economic effects. The information gathered from this and future surveys will inform wheat variety development and aid in management decisions made by growers across the state.

Progress towards small-scale field trials of coastal enhanced weathering of olivine

2021 ◽  
Author(s):  
Stephen Romaniello ◽  
Shanee Stopnitzky ◽  
Tom Green ◽  
Francesc Montserrat ◽  
Eric Matzner ◽  
...  
Keyword(s):  
Real World ◽  
Field Experiments ◽  
Ecological Impact ◽  
Field Trials ◽  
Research Strategy ◽  
Unintended Consequences ◽  
Ecological Impacts ◽  
Small Scale ◽  
Climate Mitigation ◽  
Stage Of Development

<p>Slow progress towards achieving global greenhouse gas emissions targets significantly increases the likelihood that future climate efforts may require not only emissions cuts but also direct climate mitigation via negative emissions technologies (IPCC AR5). Currently, such technologies exist at only a nascent stage of development, with significant uncertainties regarding their feasibility, cost, and potential unintended consequences and/or co-benefits.</p><p>Coastal enhanced weathering of olivine (CEWO) has been suggested as one potential pathway for achieving net negative CO<sub>2</sub> emissions at scale. CEWO involves the mining of olivine-rich ultramafic rocks (such as dunite) for incorporation during beach augmentation and restoration work. While grinding this rock into increasingly fine particle sizes is essential for increasing its surface area and reactivity, this step is also costly and energetically expensive. CEWO attempts to minimize this cost and energy penalty by relying on wave and tidal action to provide ongoing physical weathering of olivine grains once distributed on beaches. Laboratory experiments and carbon emissions assessments of CEWO suggest that these approaches may be technically feasible and carbon negative, but significant uncertainties remain regarding the real-world kinetics of coastal olivine dissolution. Furthermore, concerns about the fate and ecological impact of nickel (Ni) and chromium (Cr)—potentially toxic trace metals found in olivine—require careful evaluation.</p><p>In 2019, Project Vesta was established as a nonprofit, philanthropically funded effort to evaluate the technical feasibility and ecological impacts of CEWO through a dedicated research program ultimately culminating in small-scale, real-world field trials of CEWO. This presentation will provide an overview and discussion of our overall research strategy, share insights from interim modeling and mesocosm experiments designed to ensure the practicality and safety of future field experiments, and explain our approach for ensuring transparent, responsible, and ethical research oversight and governance.</p>

scholarly journals Response and Modeling of Hybrid Maize Seed Vigor to Water Deficit at Different Growth Stages

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3289
Author(s):  
Rongchao Shi ◽  
Ling Tong ◽  
Taisheng Du ◽  
Manoj K. Shukla
Keyword(s):  
Water Deficit ◽  
Drip Irrigation ◽  
Field Experiments ◽  
Seed Vigor ◽  
Growth Stages ◽  
Arid Areas ◽  
Flowering Stage ◽  
Maize Production ◽  
Film Mulching ◽  
Hybrid Maize

Research is imperative to predict seed vigor of hybrid maize production under water deficit in arid areas. Field experiments were conducted in 2018 and 2019 in arid areas of northwestern China to investigate the effects of different irrigation strategies at various growth stages with drip irrigation under film mulching on grain yield, kernel weight, seed protein content, and seed vigor of hybrid maize (Zea mays L.). Water deficit at vegetative, flowering, and grain-filling stages was considered and a total of 16 irrigation treatments was applied. A total of 12 indices of germination percentage, germination index (GI), shoot length (SL), and root length (RL) under different germination conditions (standard germination and accelerated aging); electrical conductivity (EC) of the leachate; and activities of peroxidase, catalase, and superoxide dismutase in seeds were measured and analyzed using the combinational evaluation method (CEM). Furthermore, five water production functions (Blank, Stewart, Rao, Jensen, and Minhas) were used to predict seed vigor evaluated by CEM under water deficit. The results showed that leachate EC was higher under water deficit than that under sufficient irrigation. The SL, RL, and GI of different germination conditions increased under water deficit at the flowering stage. The Rao model was considered the best fitted model to predict the vigor of hybrid maize seeds under water deficit, and an appropriate water deficit at the flowering stage is recommended to ensure high seed vigor of hybrid maize production with drip irrigation under film mulching. Our findings would be useful for reducing crop water use while ensuring seed vigor for hybrid maize production in arid areas.

A COMPARISON OF INJURY AND SURVIVAL OF LARVAE OF CEPHUS CINCTUS NORT. AFTER INTRACELLULAR AND EXTRACELLULAR FREEZING

1961 ◽  
Vol 39 (3) ◽  
pp. 349-357 ◽  
Author(s):  
R. W. Salt
Keyword(s):  
Strong Evidence ◽  
Crystal Size ◽  
Activity Level ◽  
New Method ◽  
Freezing Injury ◽  
Ice Crystal ◽  
Wheat Stem Sawfly ◽  
Cephus Cinctus ◽  
Level Of Activity ◽  
Ice Crystal Size

Extracellular freezing of larvae of the wheat stem sawfly, Cephus cinctus Nort., was produced at −2.5 °C by a new method. Slow further cooling to −10, −15, or −20 °C added to extracellular ice with no intracellular freezing. Other larvae that were supercooled to and frozen at −10, −15, or −20 °C froze intracellularly. Comparisons of the effects of these two types of freezing were therefore possible at equivalent temperatures. Level of activity after freezing was used as the criterion of injury.Intracellular freezing was more injurious than extracellular freezing at −15 and −20 °C, but not at −10 °C. Injuries, as well as differences in injury due to type of freezing, decreased gradually to insignificance above −10 °C. Although larvae frozen extracellularly held an initial advantage over those frozen intracellularly, survivors of the latter group retained their vitality better, probably because they lost weight more slowly.Differences in injury and in activity level after freezing at −15 and −20 °C were insufficient to justify the use of freezing site (intracellular or extracellular) as a principal basis for explaining freezing injury. The same conclusion applies to ice crystal size and configuration, which differed vastly in the two types of freezing.These conclusions depend on whether freezing was actually intracellular or extracellular as represented. Strong evidence is presented that freezing was in fact as specified.

Team interaction challenges for medical leadership

BMJ Leader ◽  
2018 ◽  
Vol 2 (1) ◽  
pp. 32-39
Author(s):  
Stephen John McGuire
Keyword(s):  
Quantitative Data ◽  
Online Course ◽  
Self Assessment ◽  
Team Interaction ◽  
Stage Of Development ◽  
Significant Difference ◽  
Medical Directors ◽  
Medical Leadership ◽  
Giving Feedback ◽  
Assessment Questionnaire

BackgroundTeam interaction in medical practice directly affects patients, organisations and individual doctors. This study aimed to gather a set of quantitative data to identify (1) the aspects of team performance where doctors are comfortable and (2) where to focus development activities.MethodsDoctors were invited to undertake a 1-hour online course exploring concepts related to team formation, performance and dysfunction. This included completing the Healthy Team Member Self-Assessment questionnaire, designed specifically to collect the desired quantitative data. Questionnaire responses were then collated as a survey and analysed in line with the study’s aims.Results202 participants completed the questionnaire including 45 consultants, 85 doctors in training, 24 locums, 3 medical directors, 6 general practitioners and 35 other doctors. Five practice or hospital managers and five other healthcare professionals also submitted results. Collective analysis of the participants’ self-assessment reveals a number of behaviours where doctors indicate improvements are required, including: 45% are not challenging or giving feedback to their colleagues, 42% not proactively seeking honest feedback, 40% not discussing progress towards goals and 39% not discussing support they require to fulfil their role. In addition, unhelpful disparities of perception within teams are suggested. A Wilcoxon-Mann-Whitney test confirmed a statistically significant difference between the 33% of consultants who state their team is in the unproductive ‘Storming’ stage of development and just 12% of all other participants stating the same (P=0.0008). Feelings of ‘I am committed but others are not’ and ‘I am willing to help others but they are not willing to help me’ are also suggested.ConclusionsThe author relates these issues to the duty of candour, proposing that both individual doctors and medical leadership have responsibilities to ensure improvements. In particular, individual doctors should ensure ongoing development in team interaction skills, and medical leadership must foster the appropriate culture for individuals to function within real teams.

Sign in / Sign up

Export Citation Format

Share Document