Background: Investigate the probable insect vector transmitting the GBNV in blackgram.&nbsp; 
 
Methods: GBNV isolate maintained on cowpea for transmission studies under greenhouse conditions. RT PCR has been employed to know the presence of GBNV before and after transmission studies. Various interval periods have been fixed to investigate AAP, IAP and number of larvae required to transmit the virus was also determined. 
 
Result: Among the two species tested for GBNV transmission in blackgram, only T. palmi successfully transmitted GBNV whereas M. usitatus, failed to transmit the virus. Therefore, Thrips palmi was identified as the vector for Groundnut bud necrosis virus in blackgram. A minimum of 2 hours of acquisition access period (48 IAP) and 4 hours of inoculation access period (24 h AAP) is needed for first instar larvae of T. palmi. A minimum of 2 h acquisition access period (with 48 h IAP), 8 h inoculation access period (24 h AAP) was observed in case of second instar larvae and a minimum of 10 larvae required to transmit the disease at 24 AAP and 48 h IAP and 2 larvae required to transmit the disease at 48 AAP and 48 h IAP. No disease transmission was observed by adults.

<div>Insights into Groundnut Bud Necrosis Virus (GBNV) Transmission by Thrips in Blackgram</div>

Background: Groundnut (Arachis hypogaea L.), a globally prominent oilseed crop, is experiencing significant losses due to the Groundnut Bud Necrosis Virus (GBNV). The extended range weather forecast (ERWF) provides timely weather information and protects crops from weather-induced biotic and abiotic risks.&nbsp; 
 
Methods: An ERWF-based GBNV disease forewarning study was conducted at Coimbatore, Tamil Nadu in 2023 and 2024. The ERWF output from Weather Research and Forecasting (WRFv4.4) with two microphysics (WSM3 and Kessler) were leveraged to forewarn the GBNV disease, using the thumb rule as adapted in Tamil Nadu Agricultural University-Agro Advisory Service (TNAU - AAS): Web cum Mobile App, which is maximum temperature (&gt;33oC), relative humidity (40-70%), wind speed (&gt;5 kmph) and rainfall (0 mm). 
 
Result: Among the two microphysics options, the WSM3 performed better and provided more usable ERWF than the Kessler scheme. The WSM3 based ERWF usability percentage was 50 to 100 for rainfall and 80-100 for all other weather variables. The higher performance of ERWF resulted in a more precise forewarning of thrips and GBNV. The first and peak activity of thrips and GBNV incidence was well correlated (70-80%) with the ERWF based forewarning.&nbsp;

Insights into Groundnut Bud Necrosis Virus (GBNV) Transmission by Thrips in Blackgram

Leveraging Extended Range Weather Forecast for Groundnut Bud Necrosis Disease Forewarning: A Data-driven Approach