Synergistic Effects of Combining Three Commercial Bioproducts Against Tuta absoluta (Meyrick) Larvae (Lepidoptera: Gelechiidae).

Abstract

&lt;b&gt;Background and Objective:&lt;/b&gt; The use of entomopathogenic agents for crop pest management is a viable alternative to synthetic chemical pesticides. &lt;i&gt;Beauveria bassiana&lt;/i&gt; (Bals.) and &lt;i&gt;Metarhizium anisopliae&lt;/i&gt; (Metsch.) are fungi considered the most promising extensively widely applied bio-control agents in protecting a wide range of economic crops. Fungal toxins are thought to play a crucial part in the pathogenicity process during insect infestation. The bioinsecticides' synergy could help to control the invasive pest more safely and effectively. &lt;b&gt;Materials and Methods:&lt;/b&gt; Suspensions of Beauveroz (&lt;i&gt;Beauveria&lt;/i&gt; &lt;i&gt;bassiana&lt;/i&gt;) and Metarhoz-P (&lt;i&gt;Metarhizium anisopliae&lt;/i&gt;), were evaluated as to their virulence against &lt;i&gt;T.&lt;/i&gt; &lt;i&gt;absoluta&lt;/i&gt; larvae at 3 different doses. As a comparison, Abamectin was utilized as a positive control, while water was used as a negative control. &lt;b&gt;Results:&lt;/b&gt; All the commercial compounds caused significant mortality among &lt;i&gt;T.&lt;/i&gt; &lt;i&gt;absoluta&lt;/i&gt; larvae, with approximately 52% mortality after 5 days of the treatment. Over 5 days, mortality of &lt;i&gt;T.&lt;/i&gt; &lt;i&gt;absoluta&lt;/i&gt; larvae when exposed to a combined treatment of &lt;i&gt;B.&lt;/i&gt; &lt;i&gt;bassiana&lt;/i&gt;, &lt;i&gt;M.&lt;/i&gt; &lt;i&gt;anisopliae&lt;/i&gt; and Abamectin reached 92%. The results under field conditions, showed significant differences (p<0.001) among these products while adding the surfactants increased the mortality larvae. Combined treatments of these 3 commercial compounds showed a synergistic effect acceded the effect obtained using each compound alone. Bio-pesticides, &lt;i&gt;B.&lt;/i&gt; &lt;i&gt;bassiana&lt;/i&gt; and &lt;i&gt;M.&lt;/i&gt; &lt;i&gt;anisopliae&lt;/i&gt; formulations caused mortality rates among &lt;i&gt;T.&lt;/i&gt; &lt;i&gt;absoluta&lt;/i&gt; larvae similar to the Abamectin treatment. &lt;b&gt;Conclusion:&lt;/b&gt; Observations indicated that both fungus candidates and Abamectin proved effective against &lt;i&gt;T. absoluta&lt;/i&gt; larvae. The combined use showed a high potentiality indicating a positive synergistic effect.