EFFICACY OF BIOPESTICIDES AND INSECTICIDES AGAINST FALL ARMYWORM, SPODOPTERA FRUGIPERDA (LEPIDOPTERA: NOCTUIDAE) ON MAIZE

ABSTRACT: The fall armyworm (FAW), Spodoptera frugiperda was first recoded in Bangladesh on November 18, 2018, FAW had posed a major threat to maize production. To assess the effectiveness of different biopesticides and insecticides against FAW, a f ield study was conducted at the Bangladesh Wheat and Maize Research Institute (BWMRI) in 6 February 2020. The study tested virus-based bio-pesticides and newly formulated organic insecticides. Results showed that chemical insecticides were generally more effective than bio-pesticides in reducing infestation during the vegetative stage. However, during the reproductive stage, both chemical and bio pesticide treatments significantly reduced cob infestation compared to untreated control plots. Among the tested insecticides, Spinosad 45SC (Tracer) provided effective control of small fresh windowpane (SFW) symptoms, maintaining low infestation levels throughout the growing stages, peaking 46% at six leaf stage (V6) and then reducing 0% at the tasseling stage. Incidence of infested whorl (IW), was minimal, with only minor occurrence at tasseling stage (10%). In contrast, Spodoptera Nuclear Polyhedrosis Virus (Spodo-NPV) was less effective at the early stages, showing high infestation levels of FAW symptoms at V6 (68%) and IW symptoms beginning at seven leaf stage (V7) (26%) and peaking at eight leaf stage (V8) (38%). However, SNPV proved effective in reducing both SFW and IW symptoms at the tasseling stage. Spodoptera frugiperda MNPV 32% (Fawligen) showed moderate control over immature larvae, with infestation levels decreasing from V6 (44%) at tasseling (0%). However, IW-type damages were more persistent, peaking at V8 (86%) and remaining at a significant level (10%) even at tasseling stage. In terms of yield, maize grain production was highest in plots treated with bio-pesticides. Fawligen-treated plots produced the highest yield (4594 ± 84 kg/ha), followed closely by Spodo-NPV (4522 ± 128 kgha-1) and Spinosad 2.5% SC (Success) (4286 ± 285 kgha-1). Based on these findings, Spodo-NPV and Fawligen are recommended for FAW control infesting maize crops, as they are both effective and safe for human health and environment. 

Keywords: Fall Armyworm, Maize yield, Spinosad, Spodoptera NPV Polyhedrosis Virus, Spodoptera frugiperda MNPV, Chlorantraniliprole