Bioassay of Some Indigenous Entomopathogens for Controlling <em>Rhynchophorus ferrugineus</em>, Olivier in Saudi Arabia

Pak J Biol Sci. 2021 Jan;24(9):944-952. doi: 10.3923/pjbs.2021.944.952.

ABSTRACT

&lt;b&gt;Background and Objective:&lt;/b&gt; The red palm weevil is a dangerous date palm pests that cannot be controlled with chemical pesticides only. As a result of the justified concerns of the negative use of synthetic insecticides on human health and the environment. So on, candidate eco-friendly micro-organisms isolated from KSA agri-ecosystems were evaluated in controlling RPW. &lt;b&gt;Materials and Methods:&lt;/b&gt; Some indigenous entomopathogenic fungi and bacteria were isolated from naturally infected RPW larvae and adults and evaluated as alternative control methods. &lt;b&gt;Results:&lt;/b&gt; The infection of RPW larvae with entomopathogenic fungi and bacteria under natural conditions was higher than in adults. &lt;i&gt;Beauveria bassiana &lt;/i&gt;was the most prevalent followed by &lt;i&gt;Aspergillus &lt;/i&gt;sp., &lt;i&gt;Metarhizium anisopliae&lt;/i&gt;, &lt;i&gt;Mucor&lt;/i&gt; sp., &lt;i&gt;Cladosporium chlorocephalum&lt;/i&gt;. In contrast, both &lt;i&gt;Bacillus&lt;/i&gt; &lt;i&gt;thuringiensis&lt;/i&gt; and &lt;i&gt;Bacillus popilliae&lt;/i&gt; formed 73.9 and 26.1%, respectively. From the 7th day, mortalities (%) increased gradually and recorded the highest mortalities with 21st days after treatment and recorded 93.33, 66.70, 53.36, 46.69 and 60.00% when treated with &lt;i&gt;B. bassiana&lt;/i&gt;, &lt;i&gt;M. anisopliae&lt;/i&gt;, &lt;i&gt;C. chlorosphalum&lt;/i&gt;, &lt;i&gt;Mucor&lt;/i&gt; sp. and &lt;i&gt;Aspergillus&lt;/i&gt; sp., respectively. &lt;b&gt;Conclusion:&lt;/b&gt; Although there was evidence indicating midgut damage and feeding inhibition among larvae that survived the treatments, instead of lower activity of &lt;i&gt;B. thuringiensis&lt;/i&gt; against &lt;i&gt;R. ferrugineus&lt;/i&gt; immature stages may refer to that, Both species of &lt;i&gt;Bacillus&lt;/i&gt; were more virulent as the days 15-21 post-treatment.

PMID:34585547 | DOI:10.3923/pjbs.2021.944.952

Source: Industry