AUTHOR=Baghouz Asmae , Bouchelta Yassir , Es-safi Imane , El Brahimi Rajae , Imtara Hamada , AlZain Mashail N. , Noman Omer M. , Shahat Abdelaaty A. , Guemmouh Raja 

TITLE=Biocidal activity of Ziziphora hispanica L and Satureja calamintha Scheele L essential oils against the Callosobruchus maculatus (Fabricius) pest on cowpea seeds during storage

JOURNAL=Frontiers in Sustainable Food Systems

VOLUME=8

YEAR=2024

URL=https://www.frontiersin.org/journals/sustainable-food-systems/articles/10.3389/fsufs.2024.1329100

DOI=10.3389/fsufs.2024.1329100

ISSN=2571-581X

ABSTRACT=<sec><title>Introduction</title><p>The post-harvest period of cowpea [<italic>Vigna unguiculata</italic> (L) Walp] is marked by substantial losses due to the insect pest <italic>Callosobruchus maculatus</italic> (Fabricius). The primary goal of the current study is to identify environmentally appropriate substitutes for synthetic pesticides in the management of stored seed pests. Thus, in a laboratory setting, the insecticidal activity of essential oils (EOs) from <italic>Ziziphora hispanica</italic> and <italic>Satureja calamintha</italic> against the cowpea weevil <italic>C. maculatus</italic> was assessed.</p></sec><sec><title>Methods</title><p>The fumigant effects of these two EOs were tested with concentrations (4, 8, 12, 16, and 20 μL L−1 of air per 10 g of cowpea seeds) on four biological parameters of C. maculatus: adult mortality, fecundity, fertility, and adult emergence, while concentrations of 4, 12, 16, and 20 μL/cm2 of air were used for the repulsion test.</p></sec><sec><title>Results and discussion</title><p>The fumigant effects of these two EOs were tested with concentrations (4, 8, 12, 16, and 20 μL L<sup>−1</sup> of air per 10  g of cowpea seeds) on four biological parameters of <italic>C. maculatus</italic>: adult mortality, fecundity, fertility, and adult emergence, while concentrations of 4, 12, 16, and 20  μL/cm<sup>2</sup> of air were used for the repulsion test. The results of fumigation tests showed a remarkable efficacy of both essential oils against adult <italic>C. maculatus</italic> after 24  h of exposure. Z<italic>. hispanica</italic> EO yielded a mortality rate of 80 ± 20%, with an LC<sub>50</sub> of 2.77 μL L<sup>−1</sup> for males and 66.66 ± 11.54% with an LC<sub>50</sub> of 3.57  μL L-1 for females at 4 μL L<sup>−1</sup> of air. However, the <italic>S. calamintha</italic> EO resulted in a mortality rate of 100% for males and 86.66 ± 23.09% with an LC<sub>50</sub> of 2.17  μL L<sup>−1</sup> for females at low doses. The fecundity was 1.33 ±  0.57 eggs per female. In contrast, this parameter was absent with <italic>S. calamintha</italic> EO at the low dose, while fertility and emerging adults were missing for both EOs. Furthermore, both EOs showed highly repellent activity towards <italic>C. maculatus</italic> adults, with 81.66% for <italic>Z. hispanica</italic> and 91.67% for <italic>S. calamintha</italic> EO. According to the results of the GC–MS analysis, the primary components of <italic>Z. hispanica</italic> EO were found to be pulegone (28.17%), alpha-naphtonitrite (10.77%), and 3-(3-thienyl) pro-2-enoic acid (10.62%). Similarly, the main constituents of <italic>S. calamintha</italic> EO were pulegone (21.48%), piperitenone oxide (17.71%), and eucalyptol (11.99%). Hence, these substances are regarded as the volatile compounds accountable for controlling <italic>C. maculatus</italic> activities. The study reports that <italic>Z. hispanica</italic> and <italic>S. calamintha</italic> show promising fumigant and repellent efficacy and offer new avenues for their potential use as an alternative to synthetic pesticides against stored seed pests.</p></sec>