SEASONAL OCCURRENCE AND NUMBER OF GENERATIONS OF LYGUS LINEOLARIS AND L. BOREALIS (HETEROPTERA: MIRIDAE) IN SOUTHERN MANITOBA

1995 ◽  
Vol 127 (4) ◽  
pp. 543-559 ◽  
Author(s):  
G.H. Gerber ◽  
I.L. Wise
Keyword(s):  
Oilseed Rape ◽  
Overlapping Generations ◽  
First Generation ◽  
Second Generation ◽  
Seasonal Occurrence ◽  
Lygus Lineolaris ◽  
Thlaspi Arvense ◽  
Two Generations ◽  
Agricultural Areas ◽  
Field Plots

AbstractThe seasonal occurrence and number of generations of Lygus lineolaris (Palisot de Beauvois) were studied on alfalfa (Medicago sativa L.), everbearing strawberries (Fragaria × ananassa Duchesne), oilseed rape (Brassica napus L.), and stinkweed (Thlaspi arvense L.) in field plots at Winnipeg, Manitoba, and in commercial alfalfa and oilseed rape fields throughout the agricultural areas of Manitoba in 1990–1993. Lygus borealis (Kelton) was studied only during 1993. Lygus lineolaris had two non-overlapping generations in southern Manitoba. Overwintered adults migrated onto host plants during die first 3 weeks of May, and females containing chorionated eggs were found in relatively small numbers for 5–6 weeks until the last 3 weeks of June. First-generation nymphs were present from the last half of May until the last half of July. During the last 2 weeks of June, the overwintered adults disappeared suddenly and were replaced completely by first-generation adults. First-generation adults eclosed during the last 2 weeks of June and in July, and first-generation females containing chorionated eggs were present for about 6–7 weeks until mid-August. Second-generation nymphs first appeared in late July or early August and most completed development by the end of September. Second-generation adults were found from the first half of August until they hibernated in October and November. Most second-generation females contained previtellogenic eggs and. therefore, were in reproductive diapause. In 3 of the 4 years, the overwintered adults appeared to include all second-generation adults plus 0–20% of the first-generation adults. The data from commercial alfalfa and oilseed rape fields indicated that the seasonal occurrence of L. lineolaris was relatively uniform in most or all agricultural areas of Manitoba. Lygus lineolaris has one generation (the second generation) on oilseed rape, and the eclosion and dispersal of reproductively active first-generation adults were well synchronized with the bud and flower stages of this host plant in southern Manitoba. In 1993, L. borealis had two generations and its seasonal occurrence was similar to that of L. lineolaris.

DEVELOPMENT OF ADULT AND NYMPHAL POPULATIONS OF LYGUS LINEOLARIS (PALISOT DE BEAUVOIS), L. ELISUS VAN DUZEE, AND L. BOREALIS (KELTON) (HETEROPTERA: MIRIDAE) IN RELATION TO SEEDING DATE AND STAGE OF PLANT DEVELOPMENT ON CANOLA (BRASSICACEAE) IN SOUTHERN MANITOBA

1997 ◽  
Vol 129 (4) ◽  
pp. 777-787 ◽  
Author(s):  
J.H.M. Leferink ◽  
G.H. Gerber
Keyword(s):  
Plant Development ◽  
Dominant Species ◽  
First Generation ◽  
Second Generation ◽  
Lygus Lineolaris ◽  
Flowering Stage ◽  
Development Stages ◽  
Seeding Date ◽  
Pod Development ◽  
Field Plots

AbstractThe development of adult and nymphal populations of Lygus lineolaris (Palisot de Beauvois), L. elisus Van Duzee, and L. borealis (Kelton) was studied in relation to seeding date and stage of plant development in four seedings of canola (cv. Westar) in field plots at Glenlea, Manitoba, in 1988 and 1989. Lygus lineolaris was the dominant species in all seedings and in both years. Colonizing adults (first-generation adults) of the three Lygus spp. first invaded the plots at about the same time from the late rosette to the early flowering stages of plant development, and Lygus adult numbers reached maxima during flowering in all seedings. The stage of plant development, and not seeding date, was important in attracting colonizing adults of Lygus to canola. Second-generation nymphs first appeared at the flowering stage of canola. All nymphal instars reached maxima and median abundances during the late flowering and pod development stages in all seedings. Second-generation adults were present from early to late pod development stages. Median abundances of second-generation adults of L. lineolaris, L. elisus, and L. borealis usually were reached at the same plant growth stage in each seeding.

Field evaluation of the suitability of four Brassica and two Sinapis species (Brassicaceae) as host plants of Lygus lineolaris (Palisot de Beauvois) (Heteroptera: Miridae)

1996 ◽  
Vol 76 (1) ◽  
pp. 203-205 ◽  
Author(s):  
G. H. Gerber
Keyword(s):  
Host Plants ◽  
First Generation ◽  
Second Generation ◽  
Field Evaluation ◽  
Lygus Lineolaris ◽  
Suitable Host ◽  
Brassica Napus L ◽  
The Mean ◽  
New Generation ◽  
Field Plots

The relative suitability of Sinapis alba L., Sinapis arvensis L., Brassica carinata A. Braun, Brassica juncea (L.) Czern, Brassica napus L., and Brassica rapa L. as host plants for Lygus lineolaris (Palisot de Beauvois) was measured by comparing the numbers of colonizing adults (first generation), nymphs (second generation), and new-generation adults (second generation) on these species in field plots during flowering and seed development in July and August 1994. The mean numbers of first-generation adults and second-generation nymphs were not significantly different on the six species of Brassica and Sinapis. The mean number of second-generation adults differed significantly on these species, but the differences were relatively small. The results indicate that the six species of Brassica and Sinapis tested are suitable host plants of L. lineolaris and have similar levels of suitability. Key words: Insecta, Miridae, Lygus lineolaris, host plants, Brassica, Sinapis

scholarly journals Toxicity and bioaccumulation of 2,2', 4,4'-tetrabromodiphenyl ether (BDE47) in a laboratory aquatic food chain

2021 ◽  
Author(s):  
Emily Rachel Awad
Keyword(s):  
Polybrominated Diphenyl Ethers ◽  
First Generation ◽  
Second Generation ◽  
Dietary Exposure ◽  
Maternal Exposure ◽  
Water Exposure ◽  
Aquatic Food Chain ◽  
Two Generations ◽  
Survival And Reproduction ◽  
Aquatic Food

Rising levels of polybrominated diphenyl ethers (PBDEs) have been ovserved in the environment, humans, and animlas. Studies have shown that these compounds can elicit toxic effects in animals (e.g. neurotoxicity and thyroid toxicity). This research investigated the effects of BDE47 on the survival and reproduction of Daphnia magna over two generations. The impacts of water-borne exposure were compared to dietary exposure using the following treatments: dosed water (DW), dosed algae (DA) and dosed water and algae (DWA). In the first generation, significant impacts on reproduction were observed in daphnids in the DA and DWA treatments. In the second generation, no significant impacts on reproduction were observed indicating a recovery from maternal exposure. When second generation daphnids were exposed to BDE47, there was high mortality in the DWA treatment anad reduced reproduction in all dosed treatments. Dietary exposure to BDE47 had a more profound impact on daphnid reproduction than water exposure. In the second generation, dietary exposure affected both survival and reproduction and water exposure reduced reproduction, indicating that maternal exposure was a factor.

Variation in Australian and Some Overseas Populations of Emex australis and E. spinosa

1979 ◽  
Vol 27 (5) ◽  
pp. 631 ◽  
Author(s):  
PW Weiss ◽  
DM Simmons
Keyword(s):  
South Africa ◽  
Western Australia ◽  
First Generation ◽  
Second Generation ◽  
Emex Australis ◽  
Hierarchical Grouping ◽  
Two Generations

Australian populations of the widespread Emex australis and the more restricted E. spinosa were tested for subspecific variation. The plants were grown for two generations in a glasshouse from seed collected from field populations. The results from growing the first generation showed that two groupings of E. australis could be made on the basis of hierarchical grouping analysis, but the populations were much more similar in the second generation and such groupings could not be made. There were no marked differences between E. australis populations from Australia and South Africa, although one from Hawaii was less vigorous than the others. Amongst Australian populations of E. spinosa, one from Western Australia was less vigorous than the others. It was also found that Australian populations of E. spinosa were generally similar to those from Portugal and slightly more vigorous than those from Morocco.

Prenatal stress effects over two generations in rats

1986 ◽  
Vol 109 (2) ◽  
pp. 239-244 ◽  
Author(s):  
I. Pollard
Keyword(s):  
Emergency Response ◽  
First Generation ◽  
Second Generation ◽  
Mature Female ◽  
Plasma Progesterone ◽  
Stress Effects ◽  
Stressed Group ◽  
Two Generations ◽  
Uterine Environment ◽  
Genetic Programme

ABSTRACT Persistent effects of stress were found in second generation rats bred from females whose own mothers had been stressed during pregnancy. The second generation rats grew more slowly, with a plateau in the growth being reached at the same age as in the controls. This resulted in adult animals of both sexes being permanently smaller than their control counterparts. When these offspring were subjected to short-term stress (one session) in adulthood, the response was not significantly different to that for the controls, indicating an intact emergency response. The male offspring from the stressed group, however, had a significantly (P < 0·01) higher plasma progesterone concentration, and a significantly (P < 0·01) lower testicular enzymic 3β-hydroxysteroid dehydrogenase activity at rest, when compared with the control offspring. The fertility of the mature female from the stressed group was not affected as a third generation of litters born did not differ from the controls. It is suggested that a changed genetic programme in the ovarian germ cells of the first generation and/or a changed uterine environment in the second generation may be implicated. J. Endocr. (1986) 109, 239–244

Seasonal Occurrence of Pieris rapae (L.) (Lepidoptera: Pieridae) in Southwest Virginia

1995 ◽  
Vol 30 (2) ◽  
pp. 262-272 ◽  
Author(s):  
David N. Gaines ◽  
L. T. Kok
Keyword(s):  
Count Data ◽  
First Generation ◽  
Pieris Rapae ◽  
Growth Period ◽  
Control Measures ◽  
Seasonal Occurrence ◽  
Fifth Generation ◽  
Sixth Generation ◽  
Field Plots ◽  
Eggs And Larvae

In Virginia, Pieris rapae (L.) phenology is not well established because earlier studies focused on its occurrence within the growth period of a particular crop. In this study, conducted in 1989 and 1990, we sampled multiple crops in both spring and fall plantings and these data were compared with those from earlier studies to obtain an overall pattern of seasonal occurrence. In 1989, spring crops of broccoli, cabbage, and kale were planted in field plots in Montgomery Co., VA, and sampled weekly for the eggs and larvae of P. rapae. In 1990, both spring and fall crops were planted and sampled. Four P. rapae generations (egg count peaks) were observed in 1989 and 1990, but comparison of data from both years suggested a fifth generation was possible in this region. When these data are compared with egg count data from seven previous years (1981–1988; 1985 not included), evidence indicates a first generation in mid-May, and consistent second and third generations in mid-June and mid-July, respectively. The June and July generations were always well defined by high egg and larva counts per plant. Less predictable are the fourth and fifth generations which may both occur in August or one generation each in August and September. When fourth and fifth generations occur in early and late August, a sixth generation may occur in late September. The regular occurrence and size of the second and third generation can facilitate the planning and implementation of biological or other control measures for P. rapae in this region.

The phenology of the emergence of brassica pod midge (Dasineura brassicae Winn.) and its infestation of winter oil-seed rape (Brasica napus L.)

1987 ◽  
Vol 108 (3) ◽  
pp. 579-589 ◽  
Author(s):  
Ingrid H. Williams ◽  
A. P. Martin ◽  
Maria Kelm
Keyword(s):  
First Generation ◽  
Second Generation ◽  
Winter Rape ◽  
Southern England ◽  
Oil Seed ◽  
Oil Seed Rape ◽  
Two Generations ◽  
Dasineura Brassicae

SummaryThe phenology of the emergence of brassica pod midge from overwintering sites and its subsequent infestation of winter oil-seed rape crops on a farm in southern England was studied over 3 years. Two generations occurred each year. The first generation of adults emerged from mid-May or early June until early July from overwintering cocoons in soil at sites where oil-seed rape had been grown in the previous year or years. Many females and a few males migrated to flowering winter rape crops where eggs were laid in the pods. Mature larvae dropped daily from the pods from early or mid-June until late July or early August, and formed cocoons in the soil. The second generation of adults emerged from late June until mid-July or early August to lay further eggs in the crop. Larvae from these eggs dropped to the soil to diapause within cocoons for up to 3 years.

scholarly journals Socialism and the Jewish Community in Slovakia

2020 ◽  
Vol 20 ◽  
Author(s):  
Peter Salner
Keyword(s):  
Oral History ◽  
Jewish Community ◽  
First Generation ◽  
Second Generation ◽  
Life Experiences ◽  
The Political ◽  
The Holocaust ◽  
Two Generations ◽  
Political Realm

This study is based on data acquired by the oral history method and discusses the reflections of two generations of Jews in relation to the socialist regime in Czechoslovakia (1948–1989). The first generation is represented by people who had survived the Holocaust. The second generation is represented by the ‘children of the Holocaust’ (born 1945–1965). They grew up at a time when the political realm was completely dominated by theCommunist Party. Their attitudes only changed with the invasion of Czechoslovakia in August 1968. This probe suggests differences which stem from contrasting life experiences.

scholarly journals Biology and harmfulness of Brassica pod midge (Dasineura brassicae Winn.) in winter oilseed rape

2015 ◽  
Vol 30 (2) ◽  
pp. 85-90
Author(s):  
Draga Graora ◽  
Ivan Sivcev ◽  
Lazar Sivcev ◽  
Wolfgang Bьchs ◽  
Vladimir Tomic ◽  
...  
Keyword(s):  
Oilseed Rape ◽  
First Generation ◽  
Yield Reduction ◽  
Winter Oilseed Rape ◽  
Ceutorhynchus Assimilis ◽  
Cabbage Seed Weevil ◽  
Two Generations ◽  
Important Pest ◽  
Cabbage Seed ◽  
Dasineura Brassicae

The Brassica pod midge (Dasineura brassicae Winn.) is an important pest in oilseed rape (Brasica napus L.). It develops two generations per year and overwinters in the larval stage in cocoons in soil. Immigration of the first generation adults lasted from the beginning of April until the end of May. Larvae developed in pods from mid-April to mid-June, causing pod deformation and cracking, which resulted in premature falling out of seeds and yield reduction. Pod damage amounted to 11.6%. The emergence of the second generation adults was detected at the end of May and in the first ten days of June. D. brassicae was found to lay eggs in healthy pods and no correlation was found with the cabbage seed weevil, Ceutorhynchus assimilis Paykull.

scholarly journals Mapping the Psychological Landscape of the Two Generations of Indian Diaspora in US through the Works of Jhumpa Lahiri

2015 ◽  
Vol 2 ◽  
Author(s):  
Jagtar Kaur Chawla ◽  
Nidhi Nema
Keyword(s):  
First Generation ◽  
Second Generation ◽  
Indian Diaspora ◽  
Indian Origin ◽  
Two Generations ◽  
Jhumpa Lahiri ◽  
Displacement Theory ◽  
First And Second Generation ◽  
The Given ◽  
Hyphenated Identity

<p>Every diasporic study or displacement theory inadvertently leads through an analysis and understanding of its governing forces <em>viz</em> socio-economic factors, culture, milieu etc. so as to arrive at any recognizable pattern of the given diasporic consciousness.</p><p>The first generation Indian diasporic sensibilities, governed majorly by the strong undercurrents of culture and traditions, stick to the natal bonds and cultural identity in foreign lands. These culture-preservation efforts are tested and challenged on several fronts externally. Ironically, the biggest threat is posed by internal agents, the second generation, who being culturally hybridized, find themselves torn between two sensibilities. Intrinsically attached to the American mainstream, they take only peripheral interest in reinforcing the ties with their roots.</p><p>The novels of the internationally acclaimed writer of the Indian origin, Jhumpa Lahiri, traverse through the psychological landscape of the first and second generation Indian immigrants in USA mapping significantly the boundaries and distances between the both. This study makes an attempt to look through Lahiri’s works at the paradigm shift between the two generations, the first generation with its ‘living within the walls’ approach and second generation with its unfixed values. The paper also analyzes the set of ‘C’s- conflicts, clashes, complexities and compromises, with a view to present the dialectics or the process of thesis, antithesis and synthesis involved in the Indian diasporic reality.</p><p><strong>Key Words- </strong>Acculturation, Deculturation, Hyphenated Identity, Hybridization, Paradox of Otherness, Breaking the Stereotypes<strong> </strong></p>

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