Studies on the transmission of Squash Leaf Curl China Virus causing yellow mosaic and leaf curl disease in pumpkin

Abstract

Viruses pose a significant threat to pumpkin cultivation, leading to substantial yield losses and reduced fruit quality. Understanding the transmission dynamics and disease progression of Squash Leaf Curl China Virus (SLCCV), a major virus affecting pumpkin, will contribute to developing effective management strategies for this crop. Our study aimed to develop an efficient mechanical inoculation method for SLCCV in pumpkin and investigate whitefly transmission. Mechanical inoculation was assessed using different buffers (I, II, and III) for preparing the viral inoculum. Buffer III, consisting of phosphate buffer, β-mercaptoethanol, and Na2SO3, showed the highest severity of symptoms and incidence of infection in the susceptible pumpkin variety Pusa Vishwas. The summer season was the most favourable for virus transmission, and plant parts such as expanded leaves, middle leaves, and stems exhibited higher infectivity than other parts. A minimum of two whiteflies per plant successfully transmitted the virus to pumpkin plants, resulting in yellow mosaic symptoms and stunted growth. The transmission efficiency increased with an increase in number of whiteflies per plant. A minimum acquisition access feeding period (AAP) of 10 min. and an inoculation access feeding period (IAP) of 24 h were optimal for whitefly-mediated transmission of SLCCV. These findings highlight the importance of vector control strategies, such as insecticides and physical barriers to prevent whitefly-mediated transmission of SLCCV in pumpkin. This is the first report of sap transmission of SLCCV in pumpkin, emphasizing the importance of developing and implementing comprehensive control strategies that address all possible routes of infection.