Laboratory experiments were carried out to evaluate the
effect of steaming cowpeas on the oviposition and larval
development of the cowpea beetle, Callosobruchus
maculatus (F.). The possibility of oven and solar drying
as well as the effect of the initial temperature of the
cowpeas on the steaming effect were also investigated.
Samples of four cowpea varieties (Soronko, Asontem,
Amantin and US Blackeye) were steamed for 10 and 15
minutes and solar or oven dried. Some initially stored
at 4°C or at room temperature were steamed for ten minutes
while other samples were oven dried, solar dried, treated
with Actellic super dust or untreated.
The results showed that when Soronko, Asontem and Amantin
cowpeas were steamed for 15 minutes and oven dried at 70
°C for 8 hours, oviposition by C. maculatus was not
significantly different from unsteamed beans. Of the
four cowpea varieties tested, US blackeye cowpeas were
most preferred as oviposition substrate and also for
larval development followed by Soronko, Asontem and
Amantin. The drying method (solar or oven drying) did
not affect oviposition of the bruchids. Significantly
fewer eggs were laid on steamed beans compared with
unsteamed beans. When US blackeye were steamed for 10 or
15 minutes and solar dried, the grains were protected
against the development of bruchid larvae comparable to
Actellic Super Dust insecticide. In contrast, steaming
blackeye cowpeas for 10 or 15 minutes and oven drying
delayed adult bruchid emergence for about 4-5 days due to
starch gelatinization and protein denaturation.
Furthermore, steaming cowpeas initially at a lower
temperature of 4°C significantly reduced oviposition in
gravid C. maculatus compared to beans at room
Fifteen or ten minutes steaming did not affect damage to
the beans so long as the seeds were solar dried to attain
safe shelf moisture levels before storage. Microscopic
examination of hatched eggs in steamed cowpeas which
failed to develop into adults showed death of larvae due
to non-utilization of the normal nutrition.
All seeds of the four varieties of cowpeas that were
steamed lost the ability to germinate.
EGYIR-YAWSON, A (2021). Thz Potential 07 Using Hydrothermal Treatment For Protection Of Stored Cowpeas.Against Callosobruchus Maculatus (F.). Afribary. Retrieved from https://afribary.com/works/thz-potential-07-using-hydrothermal-treatment-for-protection-of-stored-cowpeas-against-callosobruchus-maculatus-f
EGYIR-YAWSON, ALEX "Thz Potential 07 Using Hydrothermal Treatment For Protection Of Stored Cowpeas.Against Callosobruchus Maculatus (F.)" Afribary. Afribary, 09 Apr. 2021, https://afribary.com/works/thz-potential-07-using-hydrothermal-treatment-for-protection-of-stored-cowpeas-against-callosobruchus-maculatus-f. Accessed 30 Mar. 2023.
EGYIR-YAWSON, ALEX . "Thz Potential 07 Using Hydrothermal Treatment For Protection Of Stored Cowpeas.Against Callosobruchus Maculatus (F.)". Afribary, Afribary, 09 Apr. 2021. Web. 30 Mar. 2023. < https://afribary.com/works/thz-potential-07-using-hydrothermal-treatment-for-protection-of-stored-cowpeas-against-callosobruchus-maculatus-f >.
EGYIR-YAWSON, ALEX . "Thz Potential 07 Using Hydrothermal Treatment For Protection Of Stored Cowpeas.Against Callosobruchus Maculatus (F.)" Afribary (2021). Accessed March 30, 2023. https://afribary.com/works/thz-potential-07-using-hydrothermal-treatment-for-protection-of-stored-cowpeas-against-callosobruchus-maculatus-f