Management of the Fall Army Worm, Spodoptera  frugiperda (J.E. Smith) in Maize

The fall armyworm, Spodoptera frugiperda is a polyphagous pest and native of America, but in 2016 it was appeared in African countries (Goergen et al., 2016) and caused severe losses in Negria, Benin and Togo. This destructive invasive insect pest had been reported from Karnataka, India on maize crop during May 2018 (Sharanabasappa et al., 2018), later it was also recorded from Tamil Nadu andhra Pradesh and other states of India. It was also identified and reported from agency area of Visakhapatnam andhra Pradesh in July, 2018 (Ramesh et al., 2020). Later its spread to other asian countries, like Thailand, Sri Lanka, Bangladesh, Myanmar, Vietnam, Laos and China (Guo et al., 2018; Wu et al., 2019). It feeds on the vegetative and reproductive parts of about 80 plant species preferably gramineae family and causing severe economic losses in crops like maize, millet, soybean, cotton (Pogue, 2002), rice, other grasess and weed plants (Nabity et al., 2011). Its infestation was increasing during increase in maximum temperature (Prathima et al., 2023) and it is found that 35°C was found optimum for its fast multiplication and spread of fall army worm Shubhasree (2024).
       
The recent invasion of fall armyworm threatens the maize cultivation in India, as it is causing heavy damage to about 80 - 90% in vegetative stage. Insecticides are used widely as a tool in fall army worm management both in the America (Gutierrez-Moreno​ et al., 2019; Hardke et al., 2011; Tomquelski and Martins, 2007) and in Africa (Prasanna et al., 2018; Sisay et al., 2019). Therefore, the main objective of the study is to evaluate the efficacy of seed treatment, biological and insecticidal applications for the management of fall army worm in maize.

Study was conducted during Kharif, 2018 and 2019 at Regional Agricultural Research Station, Chintapalle, Visakhapatnam andhra Pradesh for two years. It was conducted in randomised block design (RBD) with 11 numbers of treatments in three replications with the hybrid variety VMH 6474 of maize, in 5 x 5 m² treatment plot size following all the agronomic recommended practices in its production. At the time of sowing, seed was treated with Cyantraniliprole 19.8 + Thiamethoxam 19.8FS 5 ml per kg seed irrespective of three windows and ten treatments, except in control. The eleven (11) treatments were imposed in three windows, first window at 20 DAS, second window at 35 DAS and third window at 50 DAS respectively with battery operated sprayer. The first window application with NSKE @ 5% was taken from T₁ to T5 treatments and Neem oil 1500 ppm @ 5 ml was taken from T₆ to T₁₀ treatments at 20 DAS followed by second window application with poison bait (Rice bran 10 kg + Jaggery 1 kg + 1 l. of water + 100 g Thiodicarb 75WP @ 50 kg/ha) was taken for all the treatments from T₁ to T₁₀ except control (T₁₁) at 35 DAS. The third window application includes, T₁ and T₆ with Novaluron 10EC @ 1 ml/l.; T₂ and T₇ with Chlorantraniliprole 18.5 SC @ 0.4 ml/l.; T₃ and T₈ with Spinetoram 11.7 SC @ 0.5 ml/l.; T₄ and T₉ with Spinosad 45SC @ 0.3 ml/l.; T₅ and T₁₀ with Emamectin benzoate 5 SG @ 0.4 gm/l. at 50 DAS.
       
On the basis of large plot technique, plants were counted for healthy and infested plants for calculating per cent plant infestation in treatments, before and 10 days after the window application. But for the data on number of larvae per plant, 10 plants were randomly selected from each treatment in each replication for the first window only. During Harvest, number of damaged and healthy cobs was counted for calculating per cent cob damage and yield data was taken treatment wise and calculated it for hectare.

Results revealed that all the insecticide treatments were found effective in reducing the fall army worm infestation in comparison to the control.  In this experiment, data was taken on number of larvae per plant; per cent plant infestation; per cent cob damage; yield and economics of the experiment and presented in the Table 1.


 
Number of larvae per plant
 
Number of larva per plant recorded during 01^st window of application was found non significant before (ranging from 0.68 to 1.21larva per plant) and after application with NSKE 5% (from T₁ to T₅) and Neemoil 1500 ppm @5 ml (from T₆ to T₁₀) in both the years (Kharif, 2019 and 2020), as reduction in number of larvae per plant was too low ranging from 0.45 to 0.74 in 01^st window of application compared to control 0.84 larva per plant.
       
During both the years, even though there was reduction in number of larva per plant, it was found non-significant as there is continuous egg laying and larval infestation, which lead to non significant. Similar results were reported by Deshmukh et al., (2020) that, due to continuous egg lying and larval infestations made difficult to extend management beyond 10 days even after spraying with novel insecticides. Viana and Prates (2003) were also reported the toxic effect of aqueous neem leaf extract against S. frugiperda caterpillars, which caused the mortality of S. frugiperda caterpillars.

Per cent plant infestation
 
Results reveal that, per cent plant infestation in first window application with NSKE 5% ( from T₁ to T₅) and Neemoil ( from T₆ to T₁₀) was found non significant difference between the treatments and ranged from 30.15 to 43.41%. Followed by this in the second window application, a treatment of poison bait with thiodicarb 75 WP, the per cent plant infestation at 45 DAS was found significant between the treatments and it was ranged from 4.77 to 20.96%.
       
A similar result of lowest per cent plant damage was recorded with thiodicarb poison bait by Omprakash et al., (2020). Shahanaz (2018) also concluded that emamectin benzoate, thiodicarb and chlorpyriphos were found as superior poison baits against S. litura infesting tobacco. Lunagariya et al., (2020) were also reported that poison bait with Thiodicarb found most effective in managing the population of fall army worm, which in turn reflected to higher yield.
       
Later, third window application of different treatments showed a significant difference in infestation ranged from 0.74 to 22.99% at 60 DAS. Among third window treatments, spinetoram 11.7SC 0.5 ml (T₃ with 0.74 and T₈ with 1.14%) and spinosad  45 SC 0.3 ml (T₄ with 1.35 and T₉ with 1.39%), were found effective in the management of fall army worm, followed by chlorantraniliprole 18.5 SC @ 0.4 ml (T₂ with 1.76 and T₇ with 1.25%), novaluron 10 EC @ 1 ml (T₁ with 2.23 and T₆ with 3.46%) and emamectin benzoate 5 SG  0.4 gm (T₅ with 3.22 and T₁₀ with 3.05 %) which were also on par with each other except untreated control (T₁₁) with 22.99 per cent.
       
Effectiveness of insecticides i.e. spinetoram 11.7SC, chlorantraniliprole 18.5SC, emamectin benzoate 5SG and novaluron 10EC was reported by Deshmukh et al., (2020), which is similar to current findings. Hardkeet_al(2011) also reported that chlorantraniliprole, flubendamide and novaluron were effective in reduction of infestation of larvae inn sorghum 7 days after treatment, which was 10 days after treatment in our findings. During both the years, three windows of treatments resulted in the reduction of population of fall army worm.
 
Per cent cob damage
 
During harvest, % Cob damage was ranging from 7.23 to 27.62. Lowest % cob damage was recorded in spinetoram 11.7SC @ 0.5 ml (T₃ with 7.23 and T₈ with 8.00 %) followed by chlorantraniliprole 18.5 SC @ 0.4 ml (T₂ with 9.36and T₇ with 9.73%), novaluron 10 EC @ 1 ml (T₁ with 10.17 and T₆ with 9.58%), spinosad 45 SC @ 0.3 ml (T₄ with 10.17 and T₉ with 10.17%) and emamectin benzoate 5 SG @ 0.4 gm (T₅ with 10.96 and T₁₀ with 11.25%), which were also at par with each other except untreated control with 27.62 per cent cob damage. Tandon and Srivastava (2018) also reported that diamide group insecticides were found effective against lepidopteron in rice, where our findings were also found that diamide group insecticide chlorantraniliprole was found effective in management of FAW in maize.
 
Yield
 
Among the treatments, maximum yield was recorded in spinetoram 11.7SC (T₃ with 72.55 and T₈ with 73.00q/ha), followed by chlorantraniliprole 18.5SC (T₇ with 70.82 and T₂ with 68.59 q/ha), spinosad 45SC (T₄ with 69.66 and T₉ with 68.0 q/ha), novaluron 10EC (T₁ with 68.21and T₆ with 68.34 q/ha) and emamectin benzoate 5SG (T₅ with 67.05 and T₁₀ with 66.0q/ha) which were at par with each other except control with 58.0 q/ha. Deshmukh et al., (2020) reported that chlorantraniliprole, spinetoram and emamectin benzoate were recorded least cob damage percent and higher yield, which is in line with our findings. Ramesh et al., (2020) also reported that Emamectin benzoate 5SG found effective in reduction of cob damage per cent and with maximum yield.

Fall armyworm is polyphagous and invasive insect pest which caused severe damage and loss to the farmers during the year 2018. Therefore, the main objective of the study is to evaluate the efficacy of seed treatment, biological and insecticidal applications for the management of fall army worm. So, treatments were imposed in three windows at 20, 35 and 50 DAS after seed treatment with Cyantraniliprole 19.8% + Thiamethoxam 19.8 FS @ 5 ml/kg seed. Results reveal that, seed treatment with Cyantraniliprole 19.8% + Thiamethoxam 19.8 FS was found effective up to 15 days after emergence of seed without infestation of fall army worm in comparison with control. Among three windows of applications, third window application with different insecticides was also found most significant followed by second window application (poison bait with Thiodicarb 75WP) in comparison to control (20.96) and 1st window was found non significant. Among 3rd window application treatments, spinetoram 11.7 SC @ 0.5ml (T₃ with 0.74 and T₈ with 1.14 %) and spinosad 45 SC @ 0.3 ml (T₄ with 1.35 and T₉ with 1.39 %), were found significant, followed by chlorantraniliprole 18.5 SC (T₂ with 1.76 and T₇ with 1.25 %) in the management of fall army worm. Similarly, Least Cob damage per cent (T₃ with 7.23 and T₈ with 8.00 %) and maximum yield (T₃ with 72.55 and T₈ with 73.00 q/ha) was recorded in spinetoram 11.7 SC followed by spinosad 45SC and chlorantraniliprole 18.5 SC. So, from present study spinetoram 11.7SC followed by spinosad 45SC and chlorantraniliprole 18.5 SC were found effective against S. frugiperda in Maize and seed treatment was also found most significant.

The present study was supported by the University Head (Entomology), Director of Research and University authorities of Acharya N G Ranga Agricultural University, Lam, Guntur.
 
Disclaimers
 
The views and conclusions expressed in this article are solely those of the authors and do not necessarily represent the views of their affiliated institutions. The authors are responsible for the accuracy and completeness of the information provided, but do not accept any liability for any direct or indirect losses resulting from the use of this content.
 
Informed consent
 
All animal procedures for experiments were approved by the committee of experimental animal care and handling techniques were approved by the University of Animal Care Committee.

The authors declare that there are no conflicts of interest regarding the publication of this article. No funding or sponsorship influenced the design of the study, data collection, analysis, decision to publish, or preparation of the manuscript.