EVALUATION OF PHEROMONE TRAPS, MATING DISRUPTION PASTE AND INSECTICIDES FOR Spodoptera frugiperda (J. E. Smith) IN MAIZE 3782
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Date
2023-11
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jau junagadh
Abstract
The present investigation was framed with an aim to molecular
characterization of fall armyworm in the Saurashtra region, standardization of trap
density, evaluation of mating disruption paste (MDP), bio-efficacy and persistence of
insecticides against S. frugiperda under field and laboratory conditions. The field
investigation was carried out at the farmers' field and Instructional Farm, Department
of Agronomy, while laboratory experiments were taken at the Biocontrol Research
Laboratory, Department of Entomology, Junagadh Agricultural University, Junagadh
during Kharif 2020-21 and 2021-22.
Investigations on the molecular characterization were carried out for the
identification of S. frugiperda at molecular levels from five districts (Junagadh, Gir
Somnath, Porbandar, Rajkot and Amreli) of the Saurashtra region. These studies
revealed that the presence of this pest was confirmed in all five districts and based on
the sequence available online on the NCBI GenBank portal percentage of similarity
ranged from 99.57 to 98.00%.
A study on the standardization of sex pheromone traps against S. frugiperda
noted that the sex pheromone traps installed @ 60 and 50 traps/ha recorded the lowest
(12.01-16.51% and 12.89-17.26%) per cent central shoot damage, larval population
(2.37-10.27 and 2.49-10.62 larvae/10 plants), cob damage (12.07 and 13.08%) and
moth catches (27.34 and 25.98 moths/trap/week), respectively. The study concluded
that a trap density of 50 pheromone traps per hectare was optimal for managing fall
armyworm infestation in maize.
The pragmatic data from the evaluation of different doses of Gir Sawaj MDP
showed that the two applications of Gir Sawaj MDP @ 600 g/ha or 400 g/ha showed
the lowest percentages of central shoot damage, larval population, per cent cob
damage, moth catches and the highest cob yield. Moreover, Gir Sawaj MDP had
higher economic feasibility with ICBR as compared to farmers' practices.
ABSTRACT
Investigations on the efficacy of insecticides showed that treatments of
spinoteram 11.7 EC 0.012%, emamectin benzoate 5 SG 0.0025 and thiodicarb 75 WP
0.075% were found the most effective against S. frugiperda as they recorded the
lowest per cent central shoot damage, larval population and per cent cob damage as
well as higher yield and net realization. However, chlorantraniliprole 18.5 SC 0.05%,
spinosad 45 SC 0.013%, and chlorantraniliprole 9.3 + lambda-cyhalothrin 4.6 ZC
0.006% were found next in order. The highest ICBR (1: 11.58) was obtained in
thiodicarb 75 WP 0.075% followed by emamectin benzoate 5 SG 0.0025% (1: 11.56).
During the investigation of the bio-efficacy of different insecticides under
laboratory conditions, it was found that the treatments of spinoteram 11.7 EC,
0.012%, emamectin benzoate 5 SG, 0.0025% and thiodicarb 75 WP 0.075% were
showed the cent per cent mortality after 5 days of treatment and found the most
effective against S. frugiperda under laboratory condition. Further, these insecticides
persisted for up to 10 days but exposed the persistence a strong up to 5 days of
application.
From the overall results of the present investigations, it can be concluded that
S. frugiperda is present in the five districts (Junagadh, Gir Somnath, Porbandar, Rajkot
and Amreli) of the Saurashtra region in maize. Installation of 50-60 pheromone
traps/ha or two applications of Gir Sawaj MDP @ 400-600 g/ha at 40-day intervals
was found effective pheromone base management technique. The insecticides like
spinoteram 11.7 EC, 0.012% @ 10 ml or emamectin benzoate 5 SG, 0.0025% @ 5 g
or thiodicarb 75 WP, 0.075% @ 10 g in 10 litres of water was recommended for the
management of S. frugiperda in maize. These insecticides persisted up to 10 days with
5 days of their strong effect.