Evaluation of a Bacillus thuringiensis isolate-based formulation against the pod borer, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae)

Abstract

The present study focuses on the evaluation of the potential of a Tunisian Bacillus thuringiensis (Bt) isolate named Hr1, isolated from dead and diseased pod borer, Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) larvae under laboratory and field semi-controlled conditions. The bacterial strain Hr1 showed an insecticidal activity against the pest's neonates in comparison to the spinosad-based insecticide (Tracer 240 SC®) during bioassays under laboratory conditions. A carboxymethyl cellulose-talc (CMC-talc)-based formulation of the Bt isolate was prepared to evaluate the potential of the bacterium on tomato plants infested with H. armigera under semi-controlled field conditions with and without rain simulation. The results showed the efficacy of the formulation than the spinosad-based insecticide and the treatment with unformulated bacterium. The results also showed the persistence of Bt isolate activity even after rain-wash than the treatment with unformulated bacterium.

Isolation and identification of Bacillus thuringiensis strains native of the Eastern Province of Saudi Arabia

“…Taxonomic classification of these toxins placed themes in the delta category of insect toxins because of their intracellular position (Schnepf et al 1998). Crystalline toxins or δ-endotoxins are considered the main factor conferring entomopathogenic properties to Bt (Bouslama et al 2020). δ-endotoxins are composed of 74 types of toxins and holotypes of 295 that belong to the 3D protein family synthesized by Bt (Leopoldo et al 2014).…”

Management of tomato pests using effective macrooganism (EM) bio-pesticide as alternative pests control method in Bambili, Cameroon

“…The Highest number of these pests was recorded in the untreated plot. The toxicity of B. thuringiensis on tomato pests has been reported by many authors amongst which Thameur et al (2020) [21] , in the control of H. armigera a pests of tomato in India and also by Shahini et al (2021) [19] in the control of T. absoluta in Albania, Mediterranean basin. Shaukat et al (2010) [20] confirmed the efficacy of B. thuringiensis on many other crop pests.…”

The Potential Activities of Two Bacillus thuringiensis Strains Against the Neonate Larvae of Pectinophera gossypiella

“…The obtained data were in conformity with other several studies that have proven the toxicity of different strain of Bt against some insects as Bt var. thuringiensis against the cotton leaf roller, Syllepte derogata (Gahramanova et al, 2020), Bacillus thuringiensis CAB109 on Spodoptera exigua (Huang et al, 2018), Bt against the pod borer, Helicoverpa armigera (Bouslama et al, 2020;Fite et al, 2019), Bt against P. gossypiella (Abbas et al, 2017). The LC50 values for Bt 4D1, Bt 4D4 and Bt 4G1 were 6.10, 6.62 and 8.18 μg/ml for the 2nd instar; 9.90, 10.20 and 11.12 μg/ml for the 3rd instar; and 19.82, 23.16 and 24.54 μg/ml for the 4th instar, respectively, while the Bt 4K5 and Bt 4XX4 were not toxic to Tuta absoluta (Sandeep Kumar et al, 2020).…”