Response of spodoptera frugiperda larval instars to commonly used insecticides in Tanzania
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Date
2022-12-24
Journal Title
Journal ISSN
Volume Title
Publisher
Asian Plant Research Journal
Abstract
Fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), is a polyphagous
migratory pest reported in Tanzania in 2017. Limited choices of officially registered insecticides for
the control of the pest when it first occurred led to many farmers opting for the few available ones
including those that were not registered for the pests. The current study drew from a survey
conducted in 2018 that listed the insecticides commonly used by farmers against the pest. The
study assessed the effectiveness of the insecticides against the different S. frugiperda larval instars
under field conditions in the 2019 and 2020 growing seasons. Ten commonly used insecticides
were applied to S. frugiperda damaged maize crops. Obtained results suggested a varied
effectiveness of the tested insecticides with some inflicting significant (p < 0.001) mortality of S.
frugiperda larvae while some proved ineffective. Ninja plus 5EC, Profecron 720 EC, Multi alpha
plus 150 EC and Duduba 450 EC, caused highest mortality of S. frugiperda in all experimental plots
accompanied with reduced incidences and damage severities on maize crops while Thunder 145
OD and Attakan 350 SC were the least effective. Yields obtained from the experiments suggested
a significant impact of applied insecticides whereby plots treated with Duduba 450 EC produced the
highest yield (4 tons/ha) compared to non-treated plots (2.2 tons/ha). The findings from this study
prove that some insecticides were effective against the pest while some were not. As such farmers’
complaints on the ineffectiveness of traded insecticides could be real.
Description
Original Research Article
Keywords
Spodoptera frugiperda, Fall armyworm, Insecticides, Mortality, Larval instars, Maize crop.