Evaluation of Food Additives and Low‐toxicity Compounds for the Control of Bean Rust and Wheat Leaf Rust

Abstract

The efficacy of low-toxicity chemicals as possible alternatives to synthetic fungicides for the control of Uromyces appendiculatus and Puccinia triticina was evaluated. A preliminary selection of food additives was performed through in vitro and in vivo preliminary screenings. The ED 50 and minimum inhibition concentration (MIC) values showed that most of the food additives used in this study were more toxic to U. appendiculatus than to P. triticina. Acetic acid, potassium carbonate, sodium carbonate and sodium molybdate were the food additives that were more toxic to the urediniospores of P. triticina. Selected compounds and concentrations were tested on bean and wheat plants grown in pots under controlled conditions. Acetic acid, ammonium bicarbonate, potassium acetate, potassium benzoate, potassium bicarbonate, potassium carbonate, sodium acetate and sodium citrate at 0.03, 0.09, 0.03, 0.006, 0.012, 0.012, 0.03 and 0.03 m, respectively, significantly reduced the disease severity of U. appendiculatus without causing any injury to bean leaves. Ammonium bicarbonate, potassium bicarbonate, sodium bicarbonate and sodium citrate at 0.12, 0.03, 0.12 and 0.03 m, respectively, were the most effective in reducing the disease severity caused by P. triticina without causing any injury to wheat leaves.

Comparative Efficacy of Potassium Salts Against Soil-borne and Air-borne Fungi and Their Ability to Suppress Tomato Wilt and Fruit Rots

“…These results are consistent with many other reports [17,27,[70][71][72]. In fact, these salts possess wide-spectrum antimicrobial properties and have been demonstrated to inhibit the growth of several fungal pathogens infecting stored fruits, vegetables, and ornamental species [17,[19][20][21][22]. To our knowledge, this is the first report on the in vitro antifungal activity of potassium salts against major fungal pathogens of tomato plants in Tunisia.…”

“…Potassium bicarbonates and carbonates have been demonstrated to inhibit the growth of several fungal pathogens infecting vegetables and ornamental crops at the post-harvest phase [17,[20][21][22]. In the same manner, foliage spays of sodium or potassium bicarbonates led to decreased powdery mildew severity (Leveillula taurica) in pepper plants [23].…”

“…However, PB was found to be ineffective against most tomato fruit rot pathogens even though bicarbonates were reported possess wide-spectrum antimicrobial properties; their efficacy in controlling postharvest fungal phytopathogens has been widely reported [17,[20][21][22]35,37,41,80].…”

Common Bean Rust: Pathology and Control

“…Use of these compounds can enable lower application volumes, reduced rates, and/or longer intervals between treatments. The use of food additives as an alternative control measure for U. appendiculatus was investigated by Arslan et al (2006). Potassium acetate, potassium benzoate, sodium acetate, and sodium citrate significantly reduced disease incidence on potted seedlings, without injury to bean leaves.…”

Evaluation of antifungal activity of food additives against soilborne phytopathogenic fungi

“…They also have a broad-spectrum antifungal activity (Corral et al 1988). The antifungal activity of food additives has been demonstrated on several plant-pathogens systems (Palou et al 2002a;Arslan et al 2006;Jamar et al 2007). The fungicidal efficacy of salts was tested in in vitro experiments against a soilborne pathogen Sclerotium rolfsii Sacc.…”