scholarly journals Population Dynamic of Hilda Cameroonensis Tamesse & Dongmo (Tettigometridae) Pest of Vernonia amygdalina Delile in Yaoundé-Cameroon

2021 ◽  
Vol 8 (1) ◽  
pp. 66-76
Author(s):  
Lidy Flore Dongmo ◽  
Joseph Lebel Tamesse
2017 ◽  
Author(s):  
A Quartey ◽  
A Oppong ◽  
I Ayensu ◽  
J Apenteng ◽  
D Mintah ◽  
...  

2018 ◽  
Vol 154 (2) ◽  
pp. 149-155
Author(s):  
Michael Archer

1. Yearly records of worker Vespula germanica (Fabricius) taken in suction traps at Silwood Park (28 years) and at Rothamsted Research (39 years) are examined. 2. Using the autocorrelation function (ACF), a significant negative 1-year lag followed by a lesser non-significant positive 2-year lag was found in all, or parts of, each data set, indicating an underlying population dynamic of a 2-year cycle with a damped waveform. 3. The minimum number of years before the 2-year cycle with damped waveform was shown varied between 17 and 26, or was not found in some data sets. 4. Ecological factors delaying or preventing the occurrence of the 2-year cycle are considered.


2020 ◽  
Vol 5 (2) ◽  
pp. 250-257
Author(s):  
Nurul Fatimah ◽  
◽  
Reksi Sundu

Free radicals and reactive species are widely believed to contribute to the development of several diseases by causing oxidative stress and eventually oxidative. Vernonia amygdalina (Astereacea) is a small shrub or tree between 1 and 5m high growing throughout tropical Africa. Plants are generally known as bitter leaves is well cultivated and is a general market for merchandise in several countries. The purpose of this study was to determine the antioxidant activity of hexane fraction from ethanol extract od Frican leaves (Vernonia amygdalina Del.). The method used in this study was the DPPH (1,1-Diphenil-2-Picrylhydrazyl) method. The result of phytochemical screening showed that ethanolic extract of African leaves contained a composition of secondary metabolites of alkaloids, flavonoids, tannins, steroids/triterpenoids and saponins. The antioxidant activity of the extract of n-hexane fraction was classified as very weak with an IC50 value of 317.98 ppm.


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