Field efficacy of Gliding Arc Plasma Activated Water and natural products on tomato (Solanum lycopersicum L.) late blight [Phytophthora infestans (Mont.) de Bary] severity

Abstract

This study aimed to evaluate the field efficacy of plasma-activated water (PAW) as a novel technology in agriculture together with vinegar, sodium bicarbonate, and plant aqueous extracts against tomato late blight in a complete randomised block design. Ten treatments were evaluated: Plasma activated water (PAW), a mixture of sodium bicarbonate and vinegar at different ratios (25/75, 50/50 and 75/25) and different mixtures of aqueous plant extracts made up of ten plants: Ageratum conyzoides, Eucalyptus saligna, Azadirachta indica, Panax quinquefolius, Callistemon viminalis, Euphorbia hirta, E. cordifolia Laggera pterodonta, Ocimum gratissimum and avocado pit powder. Plantizeb and distilled water were used as positive and negative controls, respectively. There was a significant difference (p < 0.05) in the growth variables between treatments at 10 weeks after transplanting (WAT). All the treatments reduced late blight severity compared to the negative control (100 %) at 10 WAT. Late blight severity on plants treated with Plantizeb, PAW, the mixture of bicarbonate and vinegar (B+V) at 50/50 (33.24 %) and the mixture of E. hirta + E. cordifolia extract (33.33 %) was the lowest and significantly comparable (p < 0.05) to Plantizeb (31.67 %). Tomato yield was 2.24 t/ha (negative control), 28.56 t/ha (Plantizeb), 27.23 t/ha (PAW), 30.32 t / ha (B+V at 50/50), and 27.69 t/ha (mixture of the aqueous extract of E. hirta + E. cordifolia). The PAW, the mixtures between B+V at 50/50, and the aqueous extract of E. hirta and E. cordifolia could be exploited for their bioactivity in late blight management in field conditions.

Keywords

• bioactivity
• plasma activated water
• euphorbia hirta
• euphorbia cordifolia
• tomato
• natural products
• late blight