Effect of some chemical inducers on chocolate spot disease of faba bean in Tunisia

Abstract

Botrytis fabae is one of the most important fungal pathogens attacking the leaves and the stem of faba bean Vicia faba L. and causes severe yield losses. This study was carried out to evaluate the effect of four chemical inducers (salicylic, citric, ascorbic and oxalic acids) and one fungicide (Carbendazim) against B. fabae in field and glasshouse conditions. Under field conditions for two seasons and glasshouse experiments, plants treated with salicylic acid showed substantial and significant decrease in the disease severity on the leaves and the stem compared with the control and the fungicide. Salicylic acid was highly effective and controlled the disease better than Carbendazim which provided only partial protection. In vitro, the inhibition of fungal growth was investigated and showed that salicylic acid was the best inhibitor of fungal growth (48%) followed by oxalic (39%), ascorbic (33%) and citric (10%) acids 6 days after incubation. An important increase of total phenols was recorded in treatment by salicylic acid in the healthy and infected leaves of faba bean 12, 24, 48, 72, 96 and 120 hours after inoculation. These promising results on the control of the main fungal disease damaging faba bean in Tunisia and other regions will have an important impact on faba bean production.

Physiological and Anatomical Responses of Faba Bean Plants Infected with Chocolate Spot Disease to Chemical Inducers

“…SA was the most effective one, followed by ascorbic acid. Plant treatment with organic acids and calcium chloride under greenhouse and/or field conditions led to a significant effect on controlling the disease and increasing phenols content as well as the activity of oxidative enzymes [ 6 ]. The results also agreed with the results of salicylic, citric, ascorbic, and oxalic acids as effective chemical inducers.…”

“…Chocolate spot disease of faba bean is caused by Botrytis fabae and B. cinerea and is considered the most important disease in the Northern region of the Egyptian Nile Delta [ 4 ], which has relatively low temperature and, at the same time, high relative humidity that favor the spread of this disease [ 5 ]. The disease causes a severe yield loss reaching 60–80% among the susceptible cultivars [ 6 ]. It decreases the total carbohydrates, nitrogen, nucleic acid, and protein contents of the yielded seeds [ 7 ].…”

Effect of Foliar Spraying Faba Bean Plants with Some Botanical Extracts and Salicylic Acid on Growth, Yield and Chocolate Spot Disease Severity

“…SA 200 ppm treatment had the highest value followed by GE 100 and OE 100 ml/L with averages of (0.821, 0.787 and 0.780), respectively. Mbazia et al (2016) found that foliar spray of faba bean with SA increased total phenols.…”

“…Chocolate spot, which caused by Botrytis fabae Sard., is one of the most yield limiting constraints of faba bean worldwide (Torres et al, 2004), as in the northern region of the Nile Delta of Egypt, where low temperature and high relative humidity favoring its spread are dominant (El-Banoby et al, 2013) cause severe yield losses reach 60-80% among the susceptible cultivars (Mbazia et al, 2016). It decreases the total carbohydrates, nitrogen, protein and nucleic acid (DNA and RNA) contents of yielded seeds (Aldesuquy, 2015).…”