SEASONAL DYNAMICS OF MARUCA VITRATA (GEYER) AND HELICOVERPA ARMIGERA (HÜBNER) ON BLACKGRAM IN RELATION TO WEATHER

Abstract

A field experiment was conducted during Zaid seasons of 2025 and 2026 at the Crop Research Centre, Sardar Vallabhbhai Patel University of Agriculture and Technology, Meerut, Uttar Pradesh, to assess seasonal incidence of Maruca vitrata and Helicoverpa armigera on blackgram in relation to prevailing weather conditions. Blackgram variety Pant Urd-31 was grown in a randomized complete block design, and weekly pest observations were recorded from untreated control plots along with temperature, relative humidity, and rainfall. During 2025, M. vitrata attained its peak population of 9.85 larvae plant⁻¹ in the 21st standard meteorological week (SMW), whereas H. armigera peaked at 8.36 larvae plant⁻¹ in the 22nd SMW. In 2026, M. vitrata again peaked in the 21st SMW at 10.56 larvae plant⁻¹, while H. armigera reached 9.65 larvae plant⁻¹ in the 20th SMW. Correlation analysis showed that evening relative humidity was significantly associated with M. vitrata in 2025, while minimum temperature was significantly associated with H. armigera. In 2026, M. vitrata showed significant positive correlations with minimum and average temperature, whereas no weather variable was significantly associated with H. armigera. Peak pest activity between the 20th and 22nd SMWs highlights the need for intensified surveillance during the reproductive stage of blackgram to support timely and need-based integrated pest management interventions.