scholarly journals Potential of seed dusts of Jatropha curcas L., Thevetia peruviana (Pers.), and Piper guineense Schumach. against the maize weevil, Sitophilus zeamais (Motschulsky, 1855) (Coleoptera: Curculionidae) in storage of corn grain

2017 ◽  
Vol 86 (3) ◽  
pp. 237-250 ◽  
Author(s):  
Oninye M. Ukpai ◽  
Briandavis N. Ibediungha ◽  
Collins N. Ehisianya

Abstract A laboratory evaluation was carried out to determine the efficacy and phytochemical composition of powdered seeds of Physic nut Jatropha curcas, Yellow oleander Thevetia peruviana and West African black pepper Piper guineense at different dosages (2.5, 5.0, 7.5 and 10.0 g) for the management of Sitophilus zeamais. Treatments were mixed with 50 g of maize and infested with 10 adult S. zeamais in 200 ml air-tight glass vials and kept under ambient conditions (25-30°C and 70-90 RH) for a period of 28 days in August 2015. The trial was laid out in a completely randomized design in four replicates. Results from data analyses showed that treated maize grains in storage recorded significantly (P < 0.05) higher mean mortality levels of adult S. zeamais than the untreated controls. However, there were no significant differences in mean mortality of the weevil at 7, 14, 21 and 28 DAT, except on those stored only for 1 DAT. Batches treated with higher doses (10.0, 7.5, 5.0 g) suffered a higher total mortality of adult S. zeamais; this was significantly (P < 0.05) higher compared with treatments using smaller dosages (2.5 and 0.0 g). Phytochemical analysis of treatments revealed high levels of alkaloids, tannins and phenols in all the plant extracts. The flavonoid contents were also high in Piper guineense and Permethrin, but lower in Jatropha curcas and Thevetia peruviana. These compounds are known to possess insecticidal properties that may have been responsible for the mortality of Sitophilus zeamais.

2018 ◽  
Vol 5 (9) ◽  
pp. 261-269
Author(s):  
Oladele A. Olaniran ◽  
Samuel A. Babarinde ◽  
Fatai O. Alao ◽  
Adetayo D. Adeleye ◽  
Afeez Ige ◽  
...  

Okra Abelmoschus esculentus (L.) Moench (Malvales: Malvaceae) is a major fruit vegetable consumed in either fresh or dried form in Africa. As part of our efforts to identify the pestiferous species attacking dried fruits, a laboratory experiment was conducted to investigate the damage potentials of Sitophilus zeamais (Motschulsky, 1855) (Coleoptera: Curculionidae) and Tribolium castaneum (Herbst, 1797) (Coleoptera: Tenebrionidae) against dried okra. Three levels of infestations (5, 10 and 20 adults of each insect) on dried okra and okra without insect infestation, which served as control were kept under ambient conditions. The experiment was laid out in completely randomized design and replicated thrice. Data were collected on percentage insect mortality, okra weight loss and proximate composition. Percentage mortality increased with storage duration, while weight loss was significantly affected by insect infestation levels and ranged from 0.04%-0.18%, 0.07%-0.21%, 0.08% 0.22%, 0.07%-022%, 0.11% 0.22% and 0.12%-0.23% for 1, 2, 3, 4, 5 and 6 weeks after infestation, respectively. Crude fibre significantly increased with insect infestation (13.98%-14.62% for the infested okra compared with 9.12%-13.63% in the control), while other proximate components were not significantly affected. The results show that the two species pose no serious threat to intact dried okra, in the short term, but long term multiple generation infestation of dried okra by the insects may cause greater damage.


2015 ◽  
Vol 5 (4) ◽  
pp. 236-243
Author(s):  
Sylvia A. Opiyo ◽  
Lawrence O. A. Manguro ◽  
Dorothy A. Okoth ◽  
Anjeline A. Ochung ◽  
Charles O. Ochieng

Insects ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 532
Author(s):  
William R. Patiño-Bayona ◽  
Leidy J. Nagles Galeano ◽  
Jenifer J. Bustos Cortes ◽  
Wilman A. Delgado Ávila ◽  
Eddy Herrera Daza ◽  
...  

Chemical control of the maize weevil (Sitophilus zeamais) has been ineffective and presents serious collateral damage. Among plant-derived insecticides, essential oils (EOs) are suitable candidates to control this stored products pest. In this work, the insecticidal activities of 45 natural EOs against S. zeamais adults were screened, and the most promising ones (24 EOs) were characterized by GC–MS. The repellent and toxic effects (contact and fumigant) of these 24 EOs were determined, and by a cluster analysis they were classified into two groups considering its fumigant activity and contact toxicity. For the EOs with the highest fumigant potential (14 oils) and their main active constituents (17 compounds), lethal concentrations were determined. The most active EOs were those obtained from L. stoechas and L. alba, with LC50 values of 303.4 and 254.1 µL/L air and characterized by a high content of monoterpenes. Regarding the major compounds, the oxygenated monoterpenes R-(+)-pulegone (LC50 = 0.580 mg/L air), S-(-)-pulegone (LC50 = 0.971 mg/L air) and R-(-)-carvone (LC50 = 1.423 mg/L air) were the most active, as few variations in their concentrations significantly increased insect mortality.


2021 ◽  
Vol 82 (1) ◽  
Author(s):  
Sobifagha Princess Bell-Gam ◽  
Luke Chinaru Nwosu ◽  
Kayode David Ileke ◽  
Uwaoma Otuodichinma Aguwa

Abstract Background The use of X-ray irradiation in the control of the maize weevil, Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) infesting stored maize was tested at 60, 70 and 80 KeV as part of the international concerted efforts to save maize production and enhance food security. Investigations were done in the laboratory at mean temperature and relative humidity of 29.2 °C and 75.7%, respectively using three varieties of maize. The possibility that X-ray irradiation can affect the viability of maize grains when planted after weevil control process was also evaluated in the laboratory. Standard methods were used to achieve the specific objectives, and X-ray machine snap constituted the exposure time for each dose. Results The results revealed 10% mortality of adult weevils after 24 h and 40% mortality after a period of 7 days. The result indicates moderate effect on mortality. Progressive increase in mortality was recorded as dose increased from 60 to 80 KeV. X-ray irradiation at the doses tested did not significantly (P > 0.05) restrict S. zeamais emergence from maize grains and did not also significantly protect grains against damage and flour production. There was no difference in the pattern of daily emergence of new progenies and pattern of accumulated emergence. The relationship between X-ray irradiation doses and weight of emerging progenies require more specific analysis. Absence of significant difference between the viability of irradiated grains and un-irradiated grains strongly suggests that X-ray irradiation did not adversely affect seed viability, and this gives irradiation technique an opportunity of higher acceptability in agriculture. Conclusions We recommend > 80 KeV of X-ray irradiation or its incorporation into integrated pest management system in order to achieve effective post-harvest control of the pest.


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