Search for content, post, videos

Impact of Weather on the Incidence of the Fall Armyworm, Spodoptera frugiperda on Maize under East Coast Agroclimatic Conditions of India

Regional Agricultural Research Station (Acharya N. G. Ranga Agricultural University), Lam, Guntur-522 034
(Andhra Pradesh), India
*(e- mail:; Mobile: 77026 06857)
(Received: October 8, 2022; Accepted: November 12, 2022)


A study on weather’s impact on the fall armyworm’s incidence on maize under East Coast agroclimatic
conditions of Andhra Pradesh, India, was studied in 2018-19 and 2019-20. The experiment consisted of
seven dates of sowings: 1st FN of July, 1st FN of August, 1st FN of September, 1st FN of October, 1st FN of
November, 1st FN of December and 1st FN of January. The results indicated a positive correlation between
the number of fall armyworm larvae/plant and its per cent infestation with Tmin, relative humidity and
rainfall when maize was sown from July to September except for Tmax. However, a negative correlation
was observed when maize was sown from October to January. The data concluded that the rainfall,
temperature and humidity significantly influenced the emergence of the fall armyworm and its infestation
on maize. The incidence of FAW started in 38th MSW (0.52 larvae/plant), and the population increased
gradually and reached the peak in the 44th MSW (1.20 larvae/plant), which coincided with the maximum
per cent infestation (53.72%) in rabi 2019. The incidence of FAW in the summer of 2020 started from the
8th MSW (0.69 larvae/plant), and reached the peak in the 12th MSW (1.69 larvae/plant), which coincided
with the maximum per cent infestation (58.33%). Correlation analysis in the rabi season revealed that
larval population and infestation showed a significant positive correlation with the evening relative
humidity (r=0.727). At the same time, maximum and minimum temperature and rainfall exhibited a
negative association with larval incidence and infestation of S. frugiperda. During the summer season,
the correlation analysis showed a positive correlation with maximum temperature (r=0.675), while
minimum temperature, morning and evening humidity and rainfall showed a negative correlation.
Key words : Seasonal incidence, correlation, rabi, summer, maize, fall armyworm