Seasonal Activity of Fall Armyworm, Spodoptera frugiperda (Smith) in Maize Agroecosystem of South Punjab, Multan, Pakistan

Abstract

Maize (Zea mays L.) holds substantial significance as a cereal crop in Pakistan. The fall armyworm (Spodoptera frugiperda) (FAW) is acknowledged as a major pest that adversely impacts the quality and yield of maize worldwide. Our research explored the dynamics of fall armyworm moth populations and the resultant damage caused by their larvae on maize crops during fall 2022 and spring 2023. Significantly, higher average moth trap catches per week were observed in September, followed by October in the fall season of 2022. In the spring season of 2023, increased moth catches were noted in March, followed by April. Moth catches exhibited a gradual ascent from crop emergence, reaching their peak during the vegetative growth stage (V8 to VT), followed by a decline from the onset of the reproductive stage and no moth catches during crop maturity to the harvesting stage (MH) in both seasons. Similarly, a significantly greater percentage of fall armyworm damage was observed in September, followed by August and October during the fall of 2022, and in March, followed by February and April during the spring of 2023. Also, higher FAW percent damage was recorded during vegetative growth of the crop (V8 to VT) and lower during the reproductive stage (R1 to R6), and no damage during maturing to harvesting (MH) during both seasons. Both sites showed no significant difference in moth catches and percent damage in both seasons. The Pearson correlation analysis of moth catches revealed a substantial positive correlation with morning relative humidity and rainfall, while the maximum temperature exhibited a significant negative correlation in both years. The insights derived from this study can help in timely management practices adopted to specific times and crop stages, thereby mitigating potential yield losses in maize cultivation.

Keywords: Maize, fall armyworm, moth population dynamics, crop growth stages, pest management