Alternaria alternata species complex impairing solanaceous vegetables in Northern parts of India: an emerging problem in Solanum lycopersicum L.

Severe incidence of Alternaria spp. was observed in the three solanaceous vegetables viz. tomato, potato and brinjal grown in National Capital Region of Delhi and Haryana. The symptomatic plants exhibited necrotic brown lesions on the leaves initiating from the lower older leaves and extending to stem, affecting the whole plant. Subsequently, black sooty sporulation was observed in fruits of tomato and brinjal crop. During the survey, tomato crop was most susceptible with 98.99% incidence, followed by brinjal with 82.36% and potato with 61.19% incidence. The mean plant disease index varied between 9.98% and 65.99% among the three crops. Isolation and characterization of the causal agent from symptomatic plants revealed association of small-spored Alternaria spp. in all crops. Further, morphological and Internal Transcribed Spacer (ITS) sequencing phylogenetic analysis ascertained the fungus belong to Alternaria section of Alternaria genus. As tomato was found most susceptible, host plant resistance was explored among 197 tomato germplasm/breeding lines under epiphytotic conditions. It was found that 08 accessions exhibited moderate resistance against pathogen. The findings in the study suggest that small-spored Alternaria is an emerging problem in the solanaceous vegetables and warrants attention for effective management of the disease.

Supplementary information: The online version contains supplementary material available at 10.1007/s13205-024-04059-7.