Combined Efficacy of Biorational Insecticides against Potato Leafworm Spodoptera litura Fabricius (Lepidoptera: Noctuidae) Under Laboratory and Field Conditions

Abstract

Armyworm species Spodoptera litura Fabricius (Lepidoptera: Noctuidae) is one of the destructive polyphagous insect pests worldwide and has attained field-evolved resistance to most of the conventional synthetic insecticides. In this study, some previously selected most effective biorational synthetic, botanical and microbial insecticidal formulations were evaluated either alone or in binary combinations against 3 rd instar larvae of S. litura under laboratory and then under the field conditions. In both trials, insecticidal treatments affected significantly the mean mortality or reduction of S. litura larvae recorded both at two and five days posttreatment. In laboratory bioassay, combinations of flubendiamide and A. indica, flubendiamide and N. tabacum and of spinetoram and A. indica formulations caused significantly high mortality (100%), followed by B. thuringensis and S. litura-NPV (94.92%) and A. indica and B. thuringensis (93.22%) and exhibited a synergized toxicity against S. litura larvae as compared to other treatments. In two years field trials, binary combination of flubendiamide and spinetoram showed an average larval reduction of 59 -100%, followed by 100% larval reduction exhibited by flubendiamide and spinetoram alone and by the combination of flubendiamide and A. indica formulations at 5 th day of application. While, minimum larval reduction was recorded for both microbial insecticides alone and in combination for both years. Overall results of this in-vitro and in-situ evaluation demonstrate the effectiveness of biorational insecticidal formulations and recommend their incorporation in integrated management of S. litura.Novelty Statement | Laboratory and then field evaluations of some promising botanical, microbial and non-conventional synthetic insecticidal formulations against 3 rd instar larvae of armyworm (Spodoptera litura) comprise the novelty of this study.

Evaluation of Integrated Pest Management Module against Pests of Ground Nut and Productivity, Profitability Analysis under Open Field Conditions

“…Imidacloprid is a chloronicotinyl insecticide used to control many sucking insects and acts upon the nicotinic receptors, kills insects by either eliciting a neural toxin response with classic toxicity symptoms (uncoordinated movement and tremoring) or by causing a reversible starvation response (shortened feeding duration, increased test probing and avoidance). Flubendiamide 39.39 SC @ 0.4 mL -1 resulted in controlling groundnut Spodoptera litura population in all three seasons consecutively and these results are in accordance with results reported by Thakur and Srivastava (2023); Muralikrishna et al (2021); Ahmad et al (2023) and Godoy et al (2023) against leaf eating caterpillar, Spodoptera litura. Flubendiamide is having unique mode of action causes multiple disruptions in the target insect's muscle function, resulting in symptoms of poisoning such as rapid feeding cessation, contractile paralysis and regurgitation that ultimately kills the insect.…”

Insecticidal activities of two fig tree leaf extracts against the cotton pest Spodoptera litura (Fab.) and their impact on the non‐target red worm Eisenia foetida (Savigny)

“…Similarly, bio‐rational extracts and essential oils derived from Azadirachita indica (Neem) were found to extend both larval and pupal stages at a high dose of 480 ppm (Ahmad et al . 2023). Correspondingly, the lethal dosage 50% (LD 50 ) of ethanolic extracts derived from C. trifoliatum reportedly decreased larval and pupal development to < 50% (Changkeb et al .…”