Unravelling Whitefly Population Dynamics and Management of Yellow Mosaic Disease in Mungbean

Yellow mosaic disease (YMD), continues to be a major production constraint in mungbean, especially under changing climatic conditions. Vector population dynamics, weather variability and sowing time play a decisive role in YMD epidemic development. The investigation aimed to elucidate the impact of fluctuations in whitefly population, interacting weather parameters and variation in sowing dates on YMD incidence and seed yield and management of the disease through chemical approach.

A field experiment was conducted during summer 2022-23 at MARS, Dharwad using susceptible mungbean variety DGGV 2 in randomized complete block design with three replications. The management experiment was laid out in randomized complete block design during summer 2023 and 2024 with 10 treatments and 3 replications. Weather data was recorded weekly and whitefly population was monitored on selected trifoliate leaves of five plants per replication. YMD incidence was assessed from 25 DAS across four sowing dates (30 Jan, 8 Feb, 14 Feb, 23 Feb). Correlation and regression analyses using SPSS and R were used to determine the influence of weather variables on whitefly dynamics and disease incidence.

Whitefly population peaked (6.60/three leaves) in the 14^th SMW under hot, dry conditions. Rainfall negatively influenced whitefly abundance (r = -0.807), while maximum temperature showed a positive association (r = 0.665). Early sowing on 30^th January resulted in the lowest YMD incidence (13.85%) and highest yield (575.56 kg/ha), whereas delayed sowings recorded higher disease and lower yields. Seed treatment with Imidacloprid 60 FS 5 ml/ kg of seeds followed by foliar spray with Thiamethaxom 25% WG 0.3 g/L at 25 days after sowing reduced the yellow disease incidence and severity. Hence early sowing aligned with low vector activity and prophylactic spray of chemicals results in effective management of the disease.