Analysis of long-term light-trap data for Helicoverpa spp. (Lepidoptera: Noctuidae) in Australia: the effect of climate and crop host plants

1999 ◽  
Vol 89 (5) ◽  
pp. 455-463 ◽  
Author(s):  
D.A. Maelzer ◽  
M.P. Zalucki

AbstractRegression analyses of a long series of light-trap catches at Narrabri, Australia, were used to describe the seasonal dynamics of Helicoverpa armigera (Hübner). The size of the second generation was significantly related to the size of the first generation, to winter rainfall, which had a positive effect, and to spring rainfall which had a negative effect. These variables accounted for up to 96% of the variation in size of the second generation from year to year. Rainfall and crop hosts were also important for the size of the third generation. The area and tonnage of many potential host crops were significantly correlated with winter rain. When winter rain was omitted from the analysis, the sizes of both the second and third generations could be expressed as a function of the size of the previous generation and of the areas planted to lucerne, sorghum and maize. Lucerne and maize always had positive coefficients and sorghum a negative one. We extended our analysis to catches of H. punctigera (Wallengren), which declines in abundance after the second generation. Winter rain had a positive effect on the sizes of the second and third generations, and rain in spring or early summer had a negative effect. Only the area grown to lucerne had a positive effect on abundance. Forecasts of pest levels from a few months to a few weeks in advance are discussed, along with the improved understanding of the seasonal dynamics of both species and the significance of crops in the management of insecticide resistance for H. armigera.

1996 ◽  
Vol 86 (5) ◽  
pp. 547-557 ◽  
Author(s):  
D. Maelzer ◽  
M.P. Zalucki ◽  
R. Laughlin

AbstractUsing regression analysis the early season dynamics of Helicoverpa punctigera (Wallengren) were determined from long series of light trap catches (10–19 years) from three sites in Australia (Narrabri and Trangie in New South Wales, and Turretfield in South Australia). The size of the second spring generation (G2, the one causing major pest problems in summer cropping regions) was strongly related to the size of the first spring generation (G1). In most cases, rainfall in early winter had a positive influence on the size of G2, whereas rainfall in spring had a negative effect. Regressions were found to account for 49 to 93% of the annual variation in G2, depending on site. The use of light trap catches and weather data to forecast pest levels from a few months to a few weeks in advance is discussed, along with the improved understanding of early season H. punctigera dynamics.


1982 ◽  
Vol 114 (2) ◽  
pp. 145-154 ◽  
Author(s):  
G. L. Ayre ◽  
W. J. Turnock ◽  
D. L. Struble

AbstractTests of intertrap variability in catches of moths of the clover cutworm, Scotogramma trifolii (Rottenberg), were conducted by placing two traps baited with an artifical sex attractant at 1 mi (1.6 km) intervals to form a grid covering 25 mi2 (64 km2) near Domain, Manitoba. The 50 traps (2/location) placed near the intersects of the grid were baited with a blend of Z-11-hexadecen-1-yl acetate and Z-11-hexadecen-1-ol. This blend was 98.6% species-specific for S. trifolii. Moth catches varied between traps and flights, but the ranking of the traps by catch was consistent during any given flight period. Up to 35 traps would be required within an area of 64 km2 (1 trap/1.8 km2) to give a population estimate within 20% of the true mean. Temperature influenced both the initiation of the flights and the number of moths caught at any given time, but there were no correlations between flights and precipitation or wind. Crop type influenced catches of S. trifolii only when moth populations were large. The catch of second generation moths averaged 9.8× the catch of first generation moths. The consistency of this relationship indicates that the annual differences in population density are controlled by variations in winter survival. The latter was linked to the induction of diapause which is governed by daylength during the larval development of the second generation.


NASPA Journal ◽  
2007 ◽  
Vol 44 (1) ◽  
Author(s):  
Carol A. Lundberg ◽  
Laurie A. Schreiner ◽  
Kristin Hovaguimian ◽  
Sharyn Slavin Miller

Using a national sample, student race/ethnicity was disaggregated into seven distinct groups (n = 643 per group) to identify unique effects of student race/ethnicity and first-generation on involvement and learning. First-generation status had a positive effect on student learning, but a negative effect on involvement. Effects by student race/ethnicity were mixed, revealing some dynamics similar to those for first-generation students and some that were unique to student race/ethnicity. Findings suggest specific programming implications based on student race/ethnicity and first-generation status.


2007 ◽  
Vol 17 (1) ◽  
pp. 32-38 ◽  
Author(s):  
Steven McArtney ◽  
Dick Unrath ◽  
J.D. Obermiller ◽  
Ann Green

Experiments were conducted in commercial apple (Malus ×domestica) orchards in the southeastern U.S. between 1998 and 2006 with the primary objective of evaluating the effects of naphthaleneacetic acid (NAA) and ethephon on return bloom. NAA increased return bloom in six of 10 experiments, whereas ethephon increased return bloom in four of seven experiments. Four biweekly applications of 5 ppm NAA during June and July (early summer NAA) increased return bloom more consistently than fewer applications. Four weekly preharvest applications of 5 ppm NAA increased return bloom of ‘Delicious’ and ‘Golden Delicious’ as effectively as early summer applications. Combining NAA and ethephon in early summer sprays did not consistently increase return bloom compared with either material alone. The flower cluster density of ‘Golden Delicious’ in the year of treatment had a negative effect on return bloom that was more pronounced on control trees than trees sprayed 5 weeks after bloom with 444 ppm ethephon (48 fl oz/acre Ethrel). Combining four early summer sprays of 316 ppm ethephon (24 fl oz/acre Ethrel) with 15 ppm gibberellin A4 + A7 (GA4+7) increased return bloom of ‘Cameo’ but had no effect on return bloom of ‘Mutsu’ or ‘Golden Delicious’. Growth regulator treatments did not have a consistent effect on fruit firmness in the year of treatment. Naphthaleneacetic acid or ethephon treatments in the on year of a biennial bearing cycle can promote return bloom of apple spurs. However, the positive effect on return bloom may be minimal in cultivars with a strong natural tendency toward biennial bearing or when bloom or initial fruit set are heavy in the year of treatment.


2021 ◽  
Author(s):  
Jing Zhang ◽  
Peter G. L. Klinkhamer ◽  
Klaas Vrieling ◽  
T. Martijn Bezemer

Abstract Background and aims Jacobaea vulgaris plants grow better in sterilized than in live soil. Foliar application of SA mitigates this negative effect of live soil on plant growth. To examine what causes the positive effect of SA application on plant growth in live soils, we analyzed the effects of SA application on the composition of active rhizosphere bacteria in the soil. Methods We studied the composition of the microbial community over four consecutive plant cycles (generations), using mRNA sequencing of the microbial communities in the rhizosphere of J. vulgaris. We initiated the experiment with an inoculum of live soil collected from the field, and at the start of each subsequent plant cycle, we inoculated a small part of the soil from the previous plant cycle into sterile bulk soil. Results Application of SA did not significantly increase or decrease the Shannon diversity at genus level within each generation, but several specific genera were enriched or depleted after foliar SA application. The composition of bacterial communities in the rhizosphere significantly differed between plant cycles (generations), but application of SA did not alter this pattern. In the first generation no genera were significantly affected by the SA treatment, but in the second, third and fourth generations, specific genera were significantly affected. 89 species out of the total 270 (32.4%) were present as the “core” microbiome in all treatments over four plant cycles. Conclusions Overall, our study shows that the composition of bacterial genera in the rhizosphere significantly differed between plant cycles, but that it was not strongly affected by foliar application of SA on J. vulgaris leaves. Further studies should examine how activation of the SA signaling pathway in the plant changes the functional genes of the rhizosphere bacterial community.


2013 ◽  
Vol 34 (3) ◽  
pp. 159-169 ◽  
Author(s):  
Sevtap Cinan ◽  
Aslı Doğan

This research is new in its attempt to take future time orientation, morningness orientation, and prospective memory as measures of mental prospection, and to examine a three-factor model that assumes working memory, mental prospection, and cognitive insight are independent but related higher-order cognitive constructs by using confirmatory factor analysis (CFA). The three-factor model produced a good fit to the data. An alternative one-factor model was tested and rejected. The results suggest that working memory and cognitive insight are distinguishable, related constructs, and that both are distinct from, but negatively associated with, mental prospection. In addition, structural equation modeling (SEM) showed that working memory had a strong positive effect on cognitive insight and a moderate negative effect on mental prospection.


2020 ◽  
Vol 3 (2) ◽  
pp. 93-108
Author(s):  
Annisa Siti Fathonah ◽  
Dadang Hermawan

This study aims to determine and analyze how much influence the bank's internal factors such as Equity, Operational Costs per Operating Income (BOPO), Financing Deposit to Ratio (FDR), Non Performing Financing (NPF) as a mediator and external or macroeconomic factors namely inflation and Gross Domestic Product (GDP) on profitability represented by Return on Assets (ROA) at Bank Muamalat Indonesia for the period 2008-2018. The data used in this research are secondary data obtained from the publication of quarterly financial statements from 2008 to quarter 2 of 2018. The method that used in this research is path analysis with SPSS 20.0 as the analytical tool. The results of the study partially test the hypothesis (t-test), in substructure I shows that the capital variable has a significant negative effect on NPF, BOPO and inflation has a significant positive effect on NPF, FDR and GDP do not significantly influence NPF at Bank Muamalat Indonesia. In substructure II partially, Capital, BOPO, significant negative effect on ROA, FDR and NPF has a significant positive effect on ROA, Inflation and GDP does not significantly influence ROA while simultaneously significantly influencing ROA. Based on the sobel test, capital has a significant effect on ROA through NPF, BOPO has a significant effect on ROA through NPF, FDR has a significant effect on ROA through NPF, Inflation has a significant effect on ROA through NPF, while GDP has no significant effect on ROA through NPF.


2020 ◽  
Vol 2 (1) ◽  
pp. 60-79
Author(s):  
Wayan Arya Paramarta ◽  
Ni Putu Kurnia Darmayanti

The aims of this study was to explain the effect of employee engagement and work stress on job satisfaction and turnover intention at Aman Villas Nusa Dua-Bali. The type of data used in this study is qualitative and quantitative data, with data sources namely primary and secondary data. Data collection method is interview, distributing questionnaires to respondents and library research, while the data analysis technique used Smart PLS 3.2.8. The results of this study showed that employee engagement had a positive effect and significant on job satisfaction, work stress had a negative effect but not significant on job satisfaction, employee engagement had a negative effect and significant on turnover intention, work stress had a positive effect and significant on turnover intention, job satisfaction had a negative effect but not significant on turnover intention, employee engagement had a positive effect but not significant on turnover intention trough job satisfaction, work stress had a positive effect but not significant on turnover intention trough job satisfaction at Aman Villas Nusa Dua-Bali.


Sign in / Sign up

Export Citation Format

Share Document