scholarly journals Bio-efficacy of Some Plants Ethanolic Extracts Against Cowpea Weevil (Callosobruchus maculatus Fabricius) Infestation of Stored Cowpea Seeds

2019 ◽  
Vol 12 (1) ◽  
pp. 16-21 ◽  
Author(s):  
Negbenebor Helen Ehimemen ◽  
Nura Salisu
2020 ◽  
Vol 81 (1) ◽  
Author(s):  
Kayode David Ileke ◽  
Jacobs Mobolade Adesina ◽  
Luke Chinaru Nwosu ◽  
Abimbola Olagunju

Abstract Background Powders and extracts of Piper guineense seeds and leaves were assessed for insecticidal activities against Callosobruchus maculatus in the laboratory at temperature and relative humidity of 29.6 °C and 75.9%, respectively. Bioactive compounds in P. guineense leaves and seeds were also investigated. The powders were tested at rates 1.0, 2.0 and 4.0 g/20 g cowpea seeds while extracts were tested at 1.0, 2.0 and 3.0%. Results Results of contact toxicity assay of the seed powder caused 100% adult mortality at 96 h post-treatment period whereas leaf powder evoked 90% adult mortality within the same period at concentration of 1.0 g/20 g cowpea seeds. Low adult emergence was observed on cowpea seeds treated with 1 g of seed powder with percentage adult emergence of 10.0% and inhibition rate (IR) of 97.5%. Beetle Perforation Index (BPI) obtained from treated cowpea seeds was significantly different (P < 0.05) from BPI of untreated seeds. Extracts of P. guineense seed were more toxic than seed powder. Piper guineense seed extract caused 87.5% adult mortality of C. maculatus while leaf extract caused 70.0% adult mortality within 24 h of infestation at concentration of 1%. Progeny development of C. maculatus was completely inhibited in cowpea treated with 2% and 3% leaf and seed extracts of P. guineense. β-Pinene was the most abundant active compound in P. guineense seed (55.6%) and leaf (48.4%). β-Phellandrene occurred 38.2% in seeds while Ocimene had the least value of 0.2% in seed and 0.5% in leaf. Conclusion The study showed that P. guineense seed powder and extracts were more effective than leaf powder and extract. Utilization of plant products as alternative to synthetic insecticides in protecting cowpea seeds against C. maculatus should be encouraged for enhanced food safety and security. Piper guineense is used as spice and medicine and interestingly safe for human use.


2011 ◽  
Vol 1 (3) ◽  
pp. 168-171
Author(s):  
J. M. Adesina ◽  
L. A. Afolabi ◽  
A. T. Aderibigbe

The efficacy of Senna occidentalis leaf powder against Callosobruchusmaculatus (F) on cowpea treated seeds was evaluated under ambientcondition (32±0.64°C and 68±3% R.H.) at the laboratory of AgriculturalTechnology of Rufus Giwa Polytechnic, Owo. C. maculatus was obtainedfrom Oja‐Oba market, Owo, Ondo State of Nigeria. The insects were rearedand bred in the laboratory. The cowpea seeds used for the bioassay werekept in the freezer for 15 days to eliminate infestation from the field. Theleaf powder was obtained after milling and four dosages of the powder (0.5,1.0, 1.5 and 2.0g) were separately admixed with 20g of cowpea in separatepetri dishes. Ten pairs of C. maculatus were introduced into each petri‐dish.Number of adult mortality, egg laid, percentage egg hatching, adultemergence and weight loss from each treatment were compared withcontrol treatment. It is concluded that the Senna occidentalis contains toxicproperties valuable for the control of C. maculatus.


2020 ◽  
Vol 2 (1) ◽  
pp. p128
Author(s):  
Mohammed Suleiman ◽  
Fatima M. Haruna

Experiments were conducted to assess the protectant ability of cow dung ash (CDA) to cowpea seeds against Callosobruchus maculatus F. under laboratory conditions of 50-65% R.H and 28-32oC. The CDA at different rates of 0.625, 1.25, 2.50, 5.00, 10.00% (w/w) incorporated with cypermethrin powder at 0.625% were applied to 20 g of cowpea seeds in petri dishes. None of the ashes or cypermethrin was added to the control. Ten beetles were introduced into each of the petri dishes and covered with muslin cloth. The experiment was arranged in a completely randomized design (CRD) and replicated three times. Effects of the treatments on adult mortalities as well as median lethal dose (LD50) of CDA against C. maculatus were determined. Adult emergence and weight losses in seeds treated with CDA at different doses were assessed. Findings of the study revealed that the adult mortality of C. maculatus among different CDA treatments differed significantly (p < 0.05) and ranged from 13.33 to 100.00% 72 hours after treatment (HAT). Results of the study also showed that LD50 of CDA against C. maculatus at 24 hours after treatment (HAT) was 5.51 % (w/w). No adults emerged from the treated seeds and weight losses were observed in those treated with the lowest dose and the control only. Therefore, CDA could be utilized to protect cowpea seeds from C. maculatus infestations during storage.


Author(s):  
R. Kooner ◽  
D.K. Sharma ◽  
K.S. Suri

Background: Pulses are an integral component of food in India which acts as major source of protein required for growth and maintenance of body. But during their storage they suffer heavy losses resulting in depletion of their quality and edibility. The present studies focused on disinfestation of green gram grains using microwaves as an alternative approach to chemical methods for controlling insects in grains and pulses. Methods: In this laboratory studies during 2017-18, the grains of green gram were infested with different life stages of the cowpea weevil and exposed to 200, 400, 600 and 800 W microwave power levels, each at an exposure period of 10, 20, 30 and 40 s. Result: Eggs were the most susceptible, while pupal and adults were the least susceptible life stages to microwave treatments. Complete mortality of eggs was achieved with microwave treatments (400, 600 and 800 W), each at an exposure period of 30 and 40 s. Complete inhibition of larval stage was attained with 400 and 600 W (30 and 40 s) and 800 W (20, 30 and 40 s exposure) while for pupal stage it was observed at the higher wattages of 600 (40 s exposure) and 800 (30 and 40 s exposure). Microwave wattage of 600 W for 40 sand 800 W for 30 and 40 s exposure caused 100% mortality of 2d old adults of cowpea bruchid.


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