scholarly journals Assessing the optimal frequency of early parasitoid releases in an apple orchard to control Dysaphis plantaginea: a proof of concept study

2021 ◽  
Author(s):  
Louise Ferrais ◽  
Kevin Tougeron ◽  
Pauline Gardin ◽  
Thierry Hance
Keyword(s):  
Apple Orchard ◽  
Control Treatment ◽  
Naturally Occurring ◽  
Aphid Control ◽  
Dysaphis Plantaginea ◽  
Mass Release ◽  
Alternative Measures ◽  
Ephedrus Cerasicola ◽  
Initial Infestation

Alternative measures to pesticides to control the rosy apple aphid Dysaphis plantaginea are being developed. Naturally occurring predators and parasitoids often fail to reduce aphid abundance below the economic threshold in orchards, because they are active too late after the aphid first infestation. We tested the efficiency of mass release of two parasitoid species, Aphidius matricariae and Ephedrus cerasicola, early in the season to match the presence of aphid fundatrix (sensitive stages). In this trial focusing on an organic apple orchard, three releases were done either every week or every two weeks to test the effect of the release frequency, during two consecutive years. The number of aphid colonies and aphid number per tree were monitored from late March to late May. Degree-days necessary for parasitoid emergence in the field after release were calculated. We show that a sufficient level of aphid control by parasitoids is reached during the first month of the survey, but control mostly fails during the second part of the monitoring session, for both release treatments, and compared to the neem oil control treatment. The relative effects of release frequencies were different between years probably because of interannual differences in aphid population dynamics and initial infestation in orchards. The field survey and the degree-day model suggest that parasitoid releases, at either frequency, are promising candidates for biological control of the rosy aphid, although the method still needs proper calibration. This conclusion needs to be reinforced by repeating the study in more orchards, but our case study lays the first empirical basis that will help to develop future control methods of aphids by parasitoid releases in apple orchards. We argue that releases should be done one to two weeks before first aphid detection to account for long development times of parasitoids at relatively low temperatures.

scholarly journals Flower strips increase the control of rosy apple aphids after parasitoid releases in an apple orchard

2022 ◽  
Author(s):  
Kévin Tougeron ◽  
Louise Ferrais ◽  
Pauline Gardin ◽  
Marc Lateur ◽  
Thierry Hance
Keyword(s):  
Biological Control ◽  
Apple Orchard ◽  
Flowering Plant ◽  
Alternative Measure ◽  
Apple Orchards ◽  
Aphid Infestation ◽  
Aphid Control ◽  
Negative Effect ◽  
Ephedrus Cerasicola

Mass releases of two parasitoid species, Aphidius matricariae and Ephedrus cerasicola, may provide an alternative measure to pesticides to control the rosy apple aphid Dysaphis plantaginea in organic apple orchards. As a proof of concept study, we tested if the presence of flower strips between apple tree rows could improve the action of three early parasitoid releases—and of other naturally present aphid enemies—on the control of aphid colonies and number of aphids per tree. Apple trees located at different distances from parasitoid release points were monitored in plots with and without flower strips in an organic apple orchard over two years, along the season of aphid infestation (March to July). Our case study demonstrated that the presence of flowering plant mixes in the alleyways of an apple orchard improved the biological control of D. plantaginea, with an effect size of 33.4% less aphids in plots with flower strips, compared to plots without flower strips, at the infestation peak date. We also showed a negative effect of higher distance to parasitoid release points on aphid control, but our results at the infestation peak date suggest that the presence of flowers could marginally compensate for the detrimental effect of distance, probably by improving the persistence and dispersal capacities of natural enemies. Despite high variations in aphid population dynamics between years, we conclude that combining flower strips with early parasitoid releases in apple orchards is promising for biological control of the rosy apple aphid, although the method merits to be further refined and repeated in more orchards.

scholarly journals Evolution of halophytes: multiple origins of salt tolerance in land plants

2010 ◽  
Vol 37 (7) ◽  
pp. 604 ◽  
Author(s):  
Timothy J. Flowers ◽  
Hanaa K. Galal ◽  
Lindell Bromham
Keyword(s):  
Salt Tolerance ◽  
Novel Species ◽  
Complex Trait ◽  
Land Plants ◽  
Salt Tolerant ◽  
Physiological Mechanisms ◽  
Multiple Origins ◽  
Naturally Occurring ◽  
Tolerant Plants

The evolution of salt tolerance is interesting for several reasons. First, since salt-tolerant plants (halophytes) employ several different mechanisms to deal with salt, the evolution of salt tolerance represents a fascinating case study in the evolution of a complex trait. Second, the diversity of mechanisms employed by halophytes, based on processes common to all plants, sheds light on the way that a plant’s physiology can become adapted to deal with extreme conditions. Third, as the amount of salt-affected land increases around the globe, understanding the origins of the diversity of halophytes should provide a basis for the use of novel species in bioremediation and conservation. In this review we pose the question, how many times has salt tolerance evolved since the emergence of the land plants some 450–470 million years ago? We summarise the physiological mechanisms underlying salt-tolerance and provide an overview of the number and diversity of salt-tolerant terrestrial angiosperms (defined as plants that survive to complete their life cycle in at least 200 mM salt). We consider the evolution of halophytes using information from fossils and phylogenies. Finally, we discuss the potential for halophytes to contribute to agriculture and land management and ask why, when there are naturally occurring halophytes, it is proving to be difficult to breed salt-tolerant crops.

Communicating emotions in L2 Chinese: Talk in the dorm during study abroad

2018 ◽  
Vol 4 (2) ◽  
pp. 337-359
Author(s):  
Qian Wu
Keyword(s):  
Study Abroad ◽  
Native Speakers ◽  
Human Interaction ◽  
Emotional Expressions ◽  
Genetic Method ◽  
Naturally Occurring ◽  
Expression Of Emotion ◽  
History Of ◽  
Oral Interaction

AbstractCommunication of emotion is at the heart of human interaction. For second language (L2) learners, the ability to communicate one’s emotion is crucial, especially in the context of study abroad when they are in frequent contact with native speakers. The aim of the case study is to investigate how an American sojourner Puppies and her Chinese roommate Kiki (both pseudonyms) participated in conversational narratives in the dormitory to construct emotions, and how the contextualized interaction facilitated Puppies’ development of a linguistic repertoire for the expression of emotion in Chinese. Informed by Vygotskian sociocultural theory, the study followed the genetic method in tracing the history of Puppies’ Chinese emotional repertoire across the semester, thereby elucidating the language developmental processes in the situated oral interaction. Audio-recorded everyday interaction in the dorm is triangulated by Puppies’ responses to the pre- and post-Mandarin Awareness Interview and interviews with Puppies and Kiki. Analysis revealed that the contextualized dorm talk provided abundant L2 resources for Puppies to develop a L2 emotional repertoire, especially fear-related emotion expressions. A discrepancy in the product of development as gleaned from the Mandarin Awareness Interview, and the process of development as seen in the naturally occurring dorm talk, suggests that Puppies’ use or non-use of local emotional expressions could be mediated by her partial understanding of the forms and the speech style and identity she wished to assume.

Specific features of supramolecular organisation and hydrogen bonding in proline cocrystals: a case study of fenamates and diclofenac

CrystEngComm ◽  
2018 ◽  
Vol 20 (43) ◽  
pp. 6970-6981 ◽  
Author(s):  
Artem O. Surov ◽  
Alexander P. Voronin ◽  
Mikhail V. Vener ◽  
Andrei V. Churakov ◽  
German L. Perlovich
Keyword(s):  
Hydrogen Bonding ◽  
Amino Acid ◽  
Naturally Occurring ◽  
Supramolecular Organisation

New zwitterionic cocrystals of fenamate drugs and diclofenac with the naturally occurring amino acid l-proline have been obtained and thoroughly characterised by a variety of experimental and theoretical techniques.

scholarly journals Response Tokens and Their Sequential Action in the Teacher Third Turn (Note 1) A Conversation Analysis Case Study in the EFL Classroom

2020 ◽  
Vol 12 (2) ◽  
pp. 26
Author(s):  
Asma Ebshiana
Keyword(s):  
Conversation Analysis ◽  
Large Study ◽  
Analysis Framework ◽  
Student Responses ◽  
Sequential Action ◽  
The Third ◽  
Naturally Occurring ◽  
Change Of State ◽  
The University

In classroom settings, students` responses are regularly evaluated through the ubiquitous three-part sequence. It is through this pattern that teachers encourage student participation. Usually, the teacher uses response tokens such as “Okay”, Right” /” Alright”, “Mhm” “Oh”, in the third turn slot. These tokens are crucial and recurrent because they show where the teacher assesses the correctness or appropriateness of the students’ responses either end the sequence or begin a turn which ends the sequence. Moreover, such tokens have an impact on the sequence expansion and on the students’ participation. This article is a part of a large study examining the overall structure of the three-part sequence in data collected in an English pre-sessional programme (PSP) at the University of Huddersfield. The present article focuses on the analysis of naturally occurring data by using Conversation Analysis framework, henceforth (CA). A deep analysis is performed to examine how response tokens as evaluative responses are constructed sequentially in the third turn sequence as a closing action, whilst considering how some responses do not act as a closing sequence, since they elaborate and invite further talk. The results of response tokens have shown that they are greatly multifaceted. The analysis concluded that not all responses do the same function in the teacher’s third turn. Apart from confirming and acknowledging the student responses and maintaining listenership, some invite further contribution, others close and shift to another topic that designates closing the sequence, and some show a “change of state”. Their functions relate to their transitions, pauses and their intonation in the on-going sequence. 

scholarly journals The role of willowherbs (Epilobium) in the recovery of vegetation cover a year after use of herbicide: a case study from Central Lithuania / Ožkarožių (Epilobium) vaidmuo atsikuriant augalijai praėjus metams po herbicido panaudojimo: tyrimas centrinėje Lietuvos dalyje

2016 ◽  
Vol 22 (2) ◽  
pp. 101-112
Author(s):  
Dalytė Matulevičiūtė
Keyword(s):  
Distribution Patterns ◽  
Apple Orchard ◽  
Life Stages ◽  
Herb Layer ◽  
Field Investigations ◽  
Initial Stage ◽  
Agricultural Weeds ◽  
Very High

Abstract Several species of willowherb (Epilobium) are considered as agricultural weeds and their prevalence has become an increasing problem in agriculture. The aim of this study was to investigate the role of willowherb plants in the initial stage of vegetation succession a year after the use of glyphosate. The study was based on the examination of thirteen willowherb specimens collected in the apple orchard of 0.2 ha area in August 2008, one month after glyphosate treatment, and vegetation field investigations in the same orchard in July 2009. The coverage of herb layer, the abundance and life stages of Epilobium plants in twenty plots of 1 m2 in size were investigated. The specimens of willowherbs, which survived the glyphosate application in 2008, were identified as Epilobium ciliatum and E. tetragonum. A year after the glyphosate treatment, the willowherb plants prevailed in the vegetation. One alien (E. ciliatum) and three native (E. hirsutum, E. parviflorum and E. tetragonum) species of willowherb were found. E. ciliatum was the most abundant. This species was characterized by the highest number of reproductive and virginile plants. E. parviflorum and E. tetragonum plants were abundant with a very high proportion of reproductive plants. Only pre-reproductive plants of E. hirsutum occurred in the study plots. The reproductive plants represented more than one third of the total number of willowherb plants. The distribution patterns of willowherb species in the plots were very variable.

Electronic Payment Systems Evaluation

2012 ◽  
Vol 3 (1) ◽  
pp. 66-80 ◽  
Author(s):  
Derek Peterson ◽  
Caroline Howard
Keyword(s):  
Historical Data ◽  
Future Research ◽  
Electronic Payment ◽  
Business Organizations ◽  
Payment Systems ◽  
Organizational Survival ◽  
Global Marketplace ◽  
Internet Service ◽  
Alternative Measures

As e-commerce is increasingly critical to organizational survival in the 21st century global marketplace, business organizations are challenged with selecting the best payment alternatives to meet both their requirements and the needs of their customers. This paper develops and validates a performance-based tool, the Electronic Payment Efficacy Quotient (EPEQ), designed to assist merchants in selecting the appropriate EPS and measuring effectiveness. The research aims at addressing the need for EPS research to aid merchant selection and use of EPS. The paper presents the case study of a single source Internet Service Provider (ISP), which was analyzed to determine merchant’s needs regarding EPS and develop measures. Historical data was then used to determine and test the validity of the most effective alternative measures. The paper concludes with recommendations for future research to assist in optimizing merchant use of EPS.

Sign in / Sign up

Export Citation Format

Share Document