Seasonal incidence of shoot fly damage on maize and its correlation with weather factors

Introduction

Maize (Zea mays L.) is a cereal crop from the Gramineae (Poaceae) family and is one of the most widely grown in the world. It is dubbed the "Queen of Cereals" due to its great adaptability and high output among cereal crops (Singh and Jaglan, 2018) [5] . Maize was first appeared in Central Mexico circa 5000 BC and now-a-days grown in tropical, subtropical and temperate climates. Maize is classified into several types: dent corn, flint corn, pod corn, popcorn, flour corn and sweet corn. Maize, with its diverse applications as food, feed and industrial raw material is essential for world food security and the agricultural economy (Anonymous, 2023) [1] . Maize is grown on over 205 million hectares in nearly 165 countries worldwide, with a production of over 1,225 million tonnes and a productivity of approximately 5.88 tonnes/ha in 2024-2025 (FAO, 2024; USDA, 2024) [2,7] . Insect pests are responsible for approximately a decrease of 31 percent in maize output, with annual economic losses estimated at 13.2% (Suman et al., 2023). Studies on the ecology and dynamics of maize pest populations have been limited to three major insect pests: C. partellus, S. inferens and A. soccata (Suman et al., 2023) [6] . Maize insect pests include stem borer, aphids, cob borer, shoot fly and fall armyworm. It is a polyphagous insect pest from the Noctuidae family that infects a variety of crops, including maize, rice, sorghum, millet, sugarcane and cotton. The pest was first identified in Africa in 2016 and quickly expanded across numerous nations, inflicting significant economic damage (Ganiger et al., 2018) [3] . Therefore, keeping in mind the above facts, the current research work was undertaken on maize.

Material and methods

The maize crop was sown on 25 th July, 2024 and 25 July, 2025 with DMRH -1410 variety, with a spacing of 60 cm x 20 cm. Observations of dead heart caused by shoot fly (%) was recorded once in a standard week on total plants in the plot, which was initiated immediately after germination and continued till crop maturity.

Statistical analysis i. Correlation and regression

Correlation and regression between independent variables (abiotic factors) and dependent variable i.e. insect population were computed by using the formula as suggested by Snedecor and Cochran (1967).

Test of significance of correlation coefficient 'r'

For testing the significance of the correlations, they were compared with the table value at (n-2) degree of freedom at 5% and 1% significant level.

Results and discussion

Kharif 2024

Observations of dead heart caused by shoot fly (%) were recorded throughout the study period during Kharif 2024 and are presented in table 1 and figure 1. The first appearance of shoot fly dead heart was recorded during 31 st SMW (8.15%) and it persisted in the crop till 37 th SMW (8.89%). The peak period was observed during 34 th SMW (32.59%), when maximum and minimum temperatures were 35.1°C and 25.9°C, respectively, morning and evening relative humidity were 86.1% and 56.6%, respectively, while the rainfall was 115.4mm per day and evaporation was 1.3mm per day.

The correlation studies indicated that minimum temperature had significant positive relationship on dead heart caused by shoot fly (%) (r = 0.54) at 5% level of significance. Whereas, maximum temperature, morning and evening relative humidity, rainfall and evaporation were found to be nonsignificant positive influence on the dead heart caused by shoot fly (%) (0.09, 0.48, 0.17, 0.28 and 0.09, respectively). Kharif 2025: Observations of dead heart cause by shoot fly (%) were recorded throughout the study period during Kharif 2025 and are presented in table 3.2 and figure 2. The first appearance of shoot fly was recorded during 31 st SMW (9.26%) and it persisted in the crop till 37 th SMW (9.63%). The peak period was observed during 34 th SMW (33.70%), when maximum and minimum temperatures were 33.3°C and 26.0°C, respectively, morning and evening relative humidity were 87.70% and 58.00%, respectively, while the rainfall was 27.70 mm per day and evaporation was 1.2 mm per day.

The correlation studies indicated that minimum temperature had significant positive relationship on dead heart caused by shoot fly (%) r= 0.57 at 5% level of significance. Whereas, maximum temperature was found to have non-significant positive influence on the dead heart caused by shoot fly (%) (0.23). However, morning and evening relative humidity, rainfall and evaporation were found to have non-significant negative influence on the dead heart caused by shoot fly (%) -0.12, -0.32, -0.10 and -0.23, respectively.

Acknowledgement

Acknowledgement: The author expresses gratitude to the Department of Entomology, RVSKVV, Gwalior, for their International Journal of Advanced Biochemistry Research https://www.biochemjournal.com valuable suggestions, unending assistance, and moral support while on the course of the investigation.

References

1. Anonymous. Economic survey of Maharashtra. 2023. p. 130.
2. FAO. Cereal Supply and Demand Brief. Food and Agriculture Organization of the United Nations. 2024.
3. Ganiger PC, Yeshwanth HM, Muralimohan K, Vinay N, Kumar ARV, Chandrashekara K. Occurrence of the new invasive pest fall armyworm in the maize fields of Karnataka, India. Current Science. 2018;115(4):621623.
4. Garg VK, Patel Y. Influence of weather parameters on population dynamics of whitefly in Kharif legumes. Annals of Plant and Soil Research. 2018;20(4):371-374.
5. Singh G, Jaglan MS. Seasonal incidence of different insect pests in Kharif maize. Journal of Pharmacognosy and Phytochemistry. 2018;7(3):3666-3669.
6. Suman S, Bhadauria NS, Tomar SPS, Singh P, Naveen. Seasonal incidence of sucking insect pests of maize and their natural enemies. The Pharma Innovation Journal. 2023;12(8):740-743.
7. USDA. World Agricultural Supply and Demand Estimates (WASDE-651). United States Department of Agriculture, Washington, D.C. 2024.