Effect of foliar-applied Euphorbia hirta towards controlling bacterial diseases in tomato crops and enhancing fruit yield and shelf life

ABSTRACT Bacterial diseases are a major cause of yield loss in tomato plants worldwide, and there is a need to identify strategies for control of these diseases. Bacterial wilt caused by Ralstonia solanacearum (RS) and bacterial spot caused by Xanthomonas axonopodis pv vesicatoria (Xav) are amongst the bacterial diseases affecting tomato crops. The current study investigates Euphorbia hirta (E. hirta) methanol extract (EHM) for its antibacterial activity against RS, and Xav induced diseases in tomato plants, along with its biostimulant potential in increasing fruit yield. EHM at 1280 mg/L exhibited 90% inhibition in the growth of both RS and Xav bacteria. Further, evaluation of EHM on Arka Vikas, a susceptible tomato variety, showed that pre-treatment of 15 days and 45 days tomato plants with 1280 mg/L EHM exhibited moderate resistance to bacterial wilt and spot disease, respectively, with increased tomato yield and improved chlorophyll b levels compared to control plants. The effectiveness of EHM in increasing fruit yield was further confirmed using field evaluation on ‘Namdhari NS 538’ variety of tomato plants. A 3.5-fold increase in numbers and weight of tomato was observed with foliar application of EHM (1280 mg/L). A significant reduction in fruit spoilage along with an increase in mRNA level of ethylene receptor factor (ERF1) was also observed. The study is the first to demonstrate the cost-effective and eco-friendly antibacterial and biostimulant potential of EHM (1280 mg/L) for tomato plants. GRAPHICAL ABSTRACT