The biology of Earias biplaga Wlk. (Lep., Noctuidae) on Theobroma cacao in Western Nigeria

1969 ◽  
Vol 58 (3) ◽  
pp. 521-536 ◽  
Author(s):  
P. F. Entwistle
Keyword(s):  
Theobroma Cacao ◽  
Ultra Violet ◽  
Dry Season ◽  
Maximum Temperature ◽  
Wet Season ◽  
Peak Period ◽  
Apical Bud ◽  
Apical Buds ◽  
Hibiscus Esculentus ◽  
The Mean

Earias biplaga Wlk. has been recorded to attack Theobroma cacao from the Ivory Coast to the Congo (Léopoldville) and also in San Thomé and is the only species of the genus to do so in Africa. Attack is most serious on seedlings in the field as the apical buds are destroyed.Eggs are laid on the stem mainly, especially on leaf bracts. The first half of the larval period is passed within the apical bud and the last half in feeding on unhardened flush leaves, or, in their absence, in burrowing down the stem below the apex or in devouring the epidermis of the upper stem.The length of the larval and pupal periods is inversely related to the mean maximum temperature; they are shortest in the dry season and longest in the wet season.Differences between the sexes exist in the wing coloration, and in the shape of the labial palps, the last segment of which is much longer in the female than in the male. The dry-season form, which has the forewings suffused with golden brown in the female and with yellow-green in the male, instead of the wet-season green, occurs from January to March in the region of Ibadan, Western Nigeria.The adults are largely nocturnal and they are attracted to ultra-violet light.Adults lived longer in the laboratory on a diet of sucrose in water (males, on average, 17 days and females, 28 days) than on water alone or without either. A mean of 95 eggs per female was recorded from sucrose-fed adults in the laboratory and the greatest number of eggs laid by a single female was 461. The peak period of oviposition was the fourth to fifth day after mating (fifth to sixth after emergence). A method of rearing E. biplaga in the laboratory is described.Six alternative host-plants in Nigeria, all in the Malvales, are listed, and one, Hibiscus esculentus, is a locally important food crop. Nine Hymenopterous parasites were found to attack E. biplaga in Western Nigeria, the most important being Trichogramma luteum (Gir.) which attacks the eggs, destroying over 90 per cent, of them at certain times of the year. All the other parasites, with one possible exception, appeared to attack only the larval stage of the host.

scholarly journals Investigation of Heavy Metals Level in selected Boreholes around the Vicinity of some Cemeteries in Benin City, Nigeria

2021 ◽  
Vol 25 (5) ◽  
pp. 841-845
Author(s):  
C.A.E. Ibhadode ◽  
I.R. Ilaboya
Keyword(s):  
Heavy Metals ◽  
Pollution Index ◽  
Mean Value ◽  
Dry Season ◽  
Wet Season ◽  
Monthly Basis ◽  
Benin City ◽  
Standard Procedures ◽  
The Mean ◽  
Mean Concentration

Groundwater pollution by heavy metals such as lead, copper, nickel and iron is one of the major environmental issues of concern which has developed into a widely studied area. In this study, attempt was made to investigate the level of heavy metals in selected boreholes around the vicinity of cemeteries in Benin City. Seventy-two (72) samples of groundwater were taken from boreholes in 9 stations around the three cemeteries in Benin City on monthly basis. The samples were analysed for 7 heavy metals, in accordance with standard procedures. The heavy metals include; Zinc, Lead Iron, Copper, Cadmium, Nickel and Mercury. From the results of the study, a variation in the mean concentration of zinc was observed. The mean concentration of zinc in site 1 was 0.450mg/l, for site 2, it was 0.140mg/l and for site 3, it was 1.0533mg/l. For iron, mean concentration was 0.072mg/l in site 1. For site 2, mean concentration of iron was 2.140mg/l and for site 3, mean concentration of iron was 0.560mg/l. It was further revealed based on the results that mean value of heavy metals in groundwater around cemeteries in Benin City were generally lower during dry season compared to wet season. In addition, result of computed pollution index (Pi) revealed that the heavy metal with the highest potential to pollute groundwater is Cadmium, with Pi of 0.5333 and 0.400 representing dry season and wet season respectively.

scholarly journals Aircraft observations of the chemical composition and aging of aerosol in the Manaus urban plume during GoAmazon 2014/5

2018 ◽  
Vol 18 (14) ◽  
pp. 10773-10797 ◽  
Author(s):  
John E. Shilling ◽  
Mikhail S. Pekour ◽  
Edward C. Fortner ◽  
Paulo Artaxo ◽  
Suzane de Sá ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Oxidation State ◽  
Biomass Burning ◽  
Urban Pollution ◽  
Organic Aerosol ◽  
Dry Season ◽  
Carbon Oxidation ◽  
Wet Season ◽  
The Mean ◽  
American Cities

Abstract. The Green Ocean Amazon (GoAmazon 2014/5) campaign, conducted from January 2014 to December 2015 in the vicinity of Manaus, Brazil, was designed to study the aerosol life cycle and aerosol–cloud interactions in both pristine and anthropogenically influenced conditions. As part of this campaign, the U.S. Department of Energy (DOE) Gulfstream 1 (G-1) research aircraft was deployed from 17 February to 25 March 2014 (wet season) and 6 September to 5 October 2014 (dry season) to investigate aerosol and cloud properties aloft. Here, we present results from the G-1 deployments focusing on measurements of the aerosol chemical composition and secondary organic aerosol (SOA) formation and aging. In the first portion of the paper, we provide an overview of the data and compare and contrast the data from the wet and dry season. Organic aerosol (OA) dominates the deployment-averaged chemical composition, comprising 80 % of the non-refractory PM1 aerosol mass, with sulfate comprising 14 %, nitrate 2 %, and ammonium 4 %. This product distribution was unchanged between seasons, despite the fact that total aerosol loading was significantly higher in the dry season and that regional and local biomass burning was a significant source of OA mass in the dry, but not wet, season. However, the OA was more oxidized in the dry season, with the median of the mean carbon oxidation state increasing from −0.45 in the wet season to −0.02 in the dry season. In the second portion of the paper, we discuss the evolution of the Manaus plume, focusing on 13 March 2014, one of the exemplary days in the wet season. On this flight, we observe a clear increase in OA concentrations in the Manaus plume relative to the background. As the plume is transported downwind and ages, we observe dynamic changes in the OA. The mean carbon oxidation state of the OA increases from −0.6 to −0.45 during the 4–5 h of photochemical aging. Hydrocarbon-like organic aerosol (HOA) mass is lost, with ΔHOA∕ΔCO values decreasing from 17.6 µg m−3 ppmv−1 over Manaus to 10.6 µg m−3 ppmv−1 95 km downwind. Loss of HOA is balanced out by formation of oxygenated organic aerosol (OOA), with ΔOOA∕ΔCO increasing from 9.2 to 23.1 µg m−3 ppmv−1. Because hydrocarbon-like organic aerosol (HOA) loss is balanced by OOA formation, we observe little change in the net Δorg∕ΔCO values; Δorg∕ΔCO averages 31 µg m−3 ppmv−1 and does not increase with aging. Analysis of the Manaus plume evolution using data from two additional flights in the wet season showed similar trends in Δorg∕ΔCO to the 13 March flight; Δorg∕ΔCO values averaged 34 µg m−3 ppmv−1 and showed little change over 4–6.5 h of aging. Our observation of constant Δorg∕ΔCO are in contrast to literature studies of the outflow of several North American cities, which report significant increases in Δorg∕ΔCO for the first day of plume aging. These observations suggest that SOA formation in the Manaus plume occurs, at least in part, by a different mechanism than observed in urban outflow plumes in most other literature studies. Constant Δorg∕ΔCO with plume aging has been observed in many biomass burning plumes, but we are unaware of reports of fresh urban emissions aging in this manner. These observations show that urban pollution emitted from Manaus in the wet season forms less particulate downwind as it ages than urban pollution emitted from North American cities.

scholarly journals Optical and Geometrical Properties of Cirrus Clouds in Amazonia Derived From 1-year of Ground-based Lidar Measurements

2016 ◽  
Author(s):  
Diego A. Gouveia ◽  
Boris Barja ◽  
Henrique M. J. Barbosa ◽  
Theotônio Pauliquevis ◽  
Paulo Artaxo
Keyword(s):  
Optical Depth ◽  
Diurnal Cycle ◽  
High Frequency ◽  
Dry Season ◽  
Cirrus Clouds ◽  
Cloud Base ◽  
Wet Season ◽  
Geometrical Properties ◽  
Lidar Ratio ◽  
The Mean

Abstract. For one year, from July 2011 to June 2012, a ground-based raman lidar provided atmospheric observations north of Manaus, Brazil, at an experimental site (2.89° S and 59.97° W) for long-term aerosol and cloud measurements. Upper tropospheric cirrus clouds were observed more frequently than previous reports in tropical regions. The frequency of occurrence was found to be as high as 82 % during the wet season and not lower than 55 % during the dry season. The diurnal cycle shows a minimum around local noon and maximum during late afternoon, associated with the diurnal cycle precipitation. Optical and geometrical characteristics of these cirrus clouds were derived. The mean values were 14.4 ± 2.0 km (top), 12.7 ± 2.3 km (base), 1.7 ± 1.5 km (thickness), and 0.36 ± 1.20 (cloud optical depth). Cirrus clouds were found at temperatures down to –90 °C and 7 % were above the tropopause base. The vertical distribution was not uniform and two cloud types were identified: (1) cloud base > 14 km and optical depth ~0.02, and (2) cloud base < 14 km and optical depth ~0.2. A third type, not previously reported, was identified during the wet season, between 16 and 18 km with optical depth ~0.005. The mean lidar ratio was 20.2 ± 7.0 sr, indicating a mixture of thick plates and long columns. However, the clouds above 14 km have a bimodal distribution during the dry season with a secondary peak at about 40 sr suggesting that thin plates are a major habit. A dependence of the lidar ratio with cloud temperature (altitude) was not found, thus indicating they are well mixed in the vertical. Cirrus clouds classified as subvisible (τ < 0.03) were 40 %, whilst 37.7 % were thin cirrus (0.03 < τ < 0.3) and 22.3 % opaque cirrus (τ > 0.3). Hence, not only does the central Amazon have a high frequency of cirrus clouds, but a large fraction of subvisible cirrus clouds as well. This high frequency of subvisible cirrus clouds may contaminate aerosol optical depth measured by sun-photometers and satellite sensors to an unknown extent.

The water intake of milking cows grazing Pangola grass (Digitaria decumbens Stent.) under wet- and dry-season conditions in Trinidad

1962 ◽  
Vol 58 (2) ◽  
pp. 257-264 ◽  
Author(s):  
P. N. Wilson ◽  
M. A. Barratt ◽  
M. H. Butterworth
Keyword(s):  
Water Intake ◽  
Free Water ◽  
Dry Season ◽  
Feed Water ◽  
Zebu Cattle ◽  
Wet Season ◽  
Drinking Habits ◽  
Digitaria Decumbens ◽  
Coefficients Of Variation ◽  
The Mean

1. The water intakes of ten Holstein × Zebu milking cows, yielding between one and two gallons of milk a day, were analysed on the basis of (a) freewater drunk, and (b) feed-water consumed with the herbage. Trials took place during a 10-day period in both the wet season, 1959 and the dry season, 1960. During both seasons the cows were rotationally grazed on Pangola grass pastures.2. The results showed a difference of only 24% in total water intake between seasons. However, the mean intake of free water increased from 18·5 lb. per cow in the wet season to 81·5 lb. per cow per day in the dry season, and the intake of feed water decreased from 94·9 to 59·2 lb. per cow per day, respectively. The between cow coefficients of variation were 9·7 and 8·7%, respectively.3. Results are presented for the drinking habits of Holstein × Zebu cattle grazing Pangola grass pastures. For 567 observed cow-days in the wet season, the cattle were found to drink water on average 0·8 times per day from troughs present in the pastures. For 332 observed cow-days in the dry season, the cattle increased their drinking habits to a mean figure of 1·4 times each day.

scholarly journals Comparing precipitation and temperature trends between inland and coastal locations

2019 ◽  
Vol 60 ◽  
pp. C109-C126 ◽  
Author(s):  
Joshua Hartigan ◽  
Shev MacNamara ◽  
Lance M Leslie
Keyword(s):  
Climate Change ◽  
Minimum Temperature ◽  
Southern Oscillation ◽  
Power Spectra ◽  
Maximum Temperature ◽  
P Value ◽  
Wet Season ◽  
Intergovernmental Panel ◽  
The Past ◽  
The Mean

Motivated by the Millennium Drought and the current drought over much of southern and eastern Australia, this detailed statistical study compares trends in annual wet season precipitation and temperature between a coastal site (Newcastle) and an inland site (Scone). Bootstrap permutation tests reveal Scone precipitation has decreased significantly over the past 40 years (p-value=0.070) whereas Newcastle has recorded little to no change (p-value=0.800). Mean maximum and minimum temperatures for Newcastle have increased over the past 40 years (p-values of 0.002 and 0.015, respectively) while the mean maximum temperature for Scone has increased (p-value = 0.058) and the mean minimum temperature has remained stable. This suggests mean temperatures during the wet season for both locations are increasing. Considering these trends along with those for precipitation, water resources in the Hunter region will be increasingly strained as a result of increased evaporation with either similar or less precipitation falling in the region. Wavelet analysis reveals that both sites have similar power spectra for precipitation and mean maximum temperature with a statistically significant signal in the two to seven year period, typically indicative of the El-Nino Southern Oscillation climate driver. The El-Nino Southern Oscillation also drives the Newcastle mean minimum temperature, whereas the Scone power spectra has no indication of a definitive driver for mean minimum temperature. References R. A., R. L. Kitching, F. Chiew, L. Hughes, P. C. D. Newton, S. S. Schuster, A. Tait, and P. Whetton. Climate change 2014: Impacts, adaptation, and vulnerability. Part B: Regional aspects. Contribution of Working Group II to the Fifth Assessment of the Intergovernmental Panel on Climate Change. Technical report, Intergovernmental Panel on Climate Change, 2014. URL https://www.ipcc.ch/report/ar5/wg2/. Bureau of Meteorology. Climate Glossary-Drought. URL http://www.bom.gov.au/climate/glossary/drought.shtml. K. M. Lau and H. Weng. Climate signal detection using wavelet transform: How to make a time series sing. B. Am. Meteorol. Soc., 76:23912402, 1995. doi:10.1175/1520-0477(1995)0762391:CSDUWT>2.0.CO;2. M. B. Richman and L. M. Leslie. Uniqueness and causes of the California drought. Procedia Comput. Sci., 61:428435, 2015. doi:10.1016/j.procs.2015.09.181. M. B. Richman and L. M. Leslie. The 20152017 Cape Town drought: Attribution and prediction using machine learning. Procedia Comput. Sci., 140:248257, 2018. doi:10.1016/j.procs.2018.10.323.

scholarly journals Future Climate Change Renders Unsuitable Conditions for Paramo Ecosystems in Colombia

2020 ◽  
Vol 12 (20) ◽  
pp. 8373
Author(s):  
Matilda Cresso ◽  
Nicola Clerici ◽  
Adriana Sanchez ◽  
Fernando Jaramillo
Keyword(s):  
Climate Change ◽  
Greenhouse Gas Emission ◽  
Dry Season ◽  
Capital City ◽  
Maximum Temperature ◽  
Future Climate Change ◽  
Mountain Range ◽  
Wet Season ◽  
Temperature And Precipitation ◽  
The Future

Paramo ecosystems are tropical alpine grasslands, located above 3000 m.a.s.l. in the Andean mountain range. Their unique vegetation and soil characteristics, in combination with low temperature and abundant precipitation, create the most advantageous conditions for regulating and storing surface and groundwater. However, increasing temperatures and changing patterns of precipitation due to greenhouse-gas-emission climate change are threatening these fragile environments. In this study, we used regional observations and downscaled data for precipitation and minimum and maximum temperature during the reference period 1960–1990 and simulations for the future period 2041–2060 to study the present and future extents of paramo ecosystems in the Chingaza National Park (CNP), nearby Colombia’s capital city, Bogotá. The historical data were used for establishing upper and lower precipitation and temperature boundaries to determine the locations where paramo ecosystems currently thrive. Our results found that increasing mean monthly temperatures and changing precipitation will render 39 to 52% of the current paramo extent in CNP unsuitable for these ecosystems during the dry season, and 13 to 34% during the wet season. The greatest loss of paramo area will occur during the dry season and for the representative concentration pathway (RCP) scenario 8.5, when both temperature and precipitation boundaries are more prone to be exceeded. Although our initial estimates show the future impact on paramos and the water security of Bogotá due to climate change, complex internal and external interactions in paramo ecosystems make it essential to study other influencing climatic parameters (e.g., soil, topography, wind, etc.) apart from temperature and precipitation.

Seasonal evapotranspiration of irrigated cotton in a low-latitude environment

1967 ◽  
Vol 18 (2) ◽  
pp. 259 ◽  
Author(s):  
WR Stern
Keyword(s):  
Meteorological Factors ◽  
Ground Cover ◽  
Dry Season ◽  
Potential Evaporation ◽  
Crop Water ◽  
Wet Season ◽  
Low Latitude ◽  
Area Index ◽  
The Mean ◽  
Dominant Influence

Evapotranspiration (Et) from irrigated cotton was determined on a sequence of plantings covering a whole year. Averaged over the year, evapotranspiration directly after irrigation (Et1) was greater than the Penman estimate of potential evaporation (E) but less than the evaporation from a standard Australian tank (Etank). The mean annual ratios were 1.2 for Et1/E and 0.9 for Et1/Etank. The rate of evapotranspiration was a function of soil moisture, declining rapidly as the available moisture fell below 60 %. Because of the high variability in the estimates of evapotranspiration it was not possible to evaluate precisely the influence of growth stage on evapotranspiration. Although there was evidence that evapotranspiration varied with the stage of growth, meteorological factors were a dominant influence because of the high watering regime. Overall, a crop planted in the wet season used little more water than a crop planted in the dry season. After the maximum leaf area index (LAI) had been reached, evapotranspiration in the wet season crop declined more rapidly and fell to a lower value than evapotranspiration during the corresponding period in the dry season crop. Water was used more efficiently by the wet season crop than by the dry season crop. The conclusion was reached that in this environment advection of energy persisted for most of the year, and that during periods of rapid height increases, particularly when ground cover was incomplete, crop surface roughness enhanced evapotranspiration. The possible interactions of some of the factors influencing evapotranspiration in a crop in the field are discussed.

A study of the growth rate of F2 and F3 Africander cross, Brahman cross and British cross cattle from birth to 18 months in a tropical environment

1971 ◽  
Vol 11 (53) ◽  
pp. 593 ◽  
Author(s):  
JF Kennedy ◽  
GIK Chirchir
Keyword(s):  
Growth Rate ◽  
Rank Order ◽  
Growth Period ◽  
Dry Season ◽  
Tropical Environment ◽  
Wet Season ◽  
Male And Female ◽  
The Mean

The mean birthweights and weaning weights of approximately 1200 male and female calves of the F2 and F3 generations of Africander cross (AX), Brahman cross (BX) and Shorthorn X Hereford cross (SH) cattle, together with the weights at four months, and nine months post weaning for approximately 500 of the females, for the years 1964-1968, are presented. BX calves (29.7 kg) were lighter at birth than AX (31.0 kg) or SH (31.8 kg), but at weaning (eight-nine months) they were 13.7 kg heavier than the AX, and 28.9 kg heavier than the SH. In the first four months postweaning, at the end of the dry-season, female AX gained 21.5 kg, BX gained 18.5 kg, and the SH 11.7 kg, and in the next five months, which included the wet-season, AX gained 78.6 kg, BX 83.1 kg, and SH 63.2 kg. At approximately eighteen months old the AX weighed 282.8 kg, BX 294.8 kg, and SH 244.2 kg. There were substantial differences between years but the rank order of the breeds at each growth period did not change.

Evaluation of management options for increasing the productivity of tropical savanna pastures. 3. Trees

1989 ◽  
Vol 29 (5) ◽  
pp. 631 ◽  
Author(s):  
WH Winter ◽  
JJ Mott ◽  
RW McLean
Keyword(s):  
Dry Season ◽  
Perennial Grasses ◽  
Fertility Level ◽  
Wet Season ◽  
Management Options ◽  
Themeda Triandra ◽  
Weight Losses ◽  
Nitrogen Concentrations ◽  
The Mean ◽  
Stocking Rates

The effect of killing trees upon the production and quality of native perennial grasses, Themeda triandra, Chrysopogon fallax, Sehima nervosum, and Sorghum plumosum, and oversown legumes from the genus Stylosanthes, was studied over 4 years at Katherine, in the semi-arid tropics of northwestern Australia. The pastures were either unfertilised or received low inputs of superphosphate, and for each fertility level were grazed at 3 stocking rates. At no time were legume yields affected by killing the trees but, in the first 3 years, the amount of grass was approximately twice as much when the trees were killed. During this period the mean grass yields declined 4-5 fold from about 2.2 t/ha. By the fourth year the advantage from tree killing upon grass yield was apparent only at the lowest stocking rates at each fertility level. Nitrogen concentrations of the grasses and legumes, with the exception of S. hamata, were increased 7 and 10% respectively above the mean annual values of 0.89 and 1.75% where the trees were killed, while the phosphorus and sulfur concentrations were not affected. Tree killing had no effect upon wet season liveweight gains during the last 2 years of the experiment. However, there were some benefits during the dry season when weight losses were lower for most treatments during the early dry season (June-September) and also lower for the lowest stocking rate treatment without fertiliser during the late dry season (October-November).

scholarly journals Overview: Precipitation Characteristics and Sensitivities to the Environmental Conditions during GoAmazon2014/5 and ACRIDICON-CHUVA

2017 ◽  
Author(s):  
Luiz A. T. Machado ◽  
Alan J. P. Calheiros ◽  
Thiago Biscaro ◽  
Scott Giangrande ◽  
Maria A. F. Silva Dias ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Land Surface ◽  
Rain Rate ◽  
Vertical Motion ◽  
Cloud Droplet ◽  
Dry Season ◽  
Wet Season ◽  
Dry Seasons ◽  
The Mean ◽  
Wet And Dry Seasons

Abstract. Abstract. This is study provides an overview of precipitation processes and their sensitivities to environmental conditions, in the Central Amazon Basin, during the GoAmazon2014/5 and ACRIDICON-CHUVA experiments. Taking advantage of the numerous measuring platforms and instruments systems operating during both campaigns sampling cloud structure and environmental conditions during 2014 and 2015, the rainfall variability among seasons, aerosol loading, land surface type, and topography have carefully been characterized. Differences between the wet and dry seasons were examined from a variety of different perspectives. The rain rate distribution, the total amount of rainfall, and the raindrop size distribution (the mean mass-weighted diameter) were quantified for the two seasons. The dry season has a higher average rain rate than the wet season and reflects more intense rain. While the cumulative wet season rainfall amount was four times larger than the total dry season rainfall, reflecting in large total rainfall accumulation. The typical size and life cycle of the Amazon cloud clusters (observed by satellite) and rain cells (observed by radar) were examined, as well their differences among the seasons. Moreover, we analyse the monthly mean thermodynamical and dynamical variables, measured by radiosondes to elucidate the differences in rainfall characteristics during the wet and dry seasons. The sensitivity of rainfall to the atmospheric aerosol loading is discussed with regard to the mean mass-weighted diameter and rain rate. This topic was evaluated during the wet season only due to the insignificant statistics of rainfall events for different ranges of aerosol loadings and the low frequency of precipitation events during the dry season. The aerosol impacts on the cloud droplet diameter is different for small and large drops. For the wet season, we observe no dependence on land surface type on the rain rate. However, during the dry season, urban areas exhibit the largest rain rate tail distribution, and deforested regions have the lowest mean rain rate. Airplane measurements were performed to characterize and contrast cloud microphysical properties and processes over forested and deforested regions. The vertical motion turned out to be uncorrelated with cloud droplet sizes, but the cloud droplets number concentration revealed a linear relationship to the vertical motion. Clouds over forest exhibit larger droplets than clouds over pastures at all cloud levels. Finally, the connections between topography and rain rate were evaluated, showing a higher rain rate over higher elevations for the dry season.

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