Select Calcium Compounds Reduce the Severity of Phytophthora Stem Rot of Soybean

Abstract

This study investigated the effects of several calcium compounds on Phytophthora stem rot of soybean (Glycine max) and fungal growth and zoospore release of a Phytophthora sojae isolate in vitro. All concentrations of five formulated calcium products [Ca(COOH)2-A, Ca(COOH)2-B, Ca(COOH)2-C, CaSO4-A, and CaCl2-A] and two chemical compounds [CaCl2 and Ca(NO3)2] applied prior to inoculation significantly suppressed disease incidence. Among all the products and chemicals, Ca(COOH)2-A was the most effective in suppressing the incidence of disease. In most cases, no significant relationship was observed between inhibition of growth rate in vitro and disease reduction in growth chamber tests. Therefore, disease suppression recorded in laboratory experiments using pathogen mycelium was likely due to the responses of plant tissues rather than the direct inhibition of pathogen fungal growth by the calcium compounds. The extent of disease reduction was related to increased calcium uptake by plants, suggesting that calcium was the effective element in reducing Phytophthora stem rot. Seedling tray experiments using zoospores indicated that the application of 10 mM Ca(COOH)2-A was more effective for reducing incidence of disease under growth chamber conditions, compared to other concentrations. The presence of 4 to 20 mM of all seven calcium solutions decreased the release of zoospores, although 0.4 mM of all compounds significantly increased zoospore release. Therefore, disease reduction in the growth-chamber experiments was due to the multiple effects of direct suppression on zoospore release and fungal growth in combination with the response of the host plant tissue to Ca(COOH)2-A.

Reducing Severity of Late Blight (Phytophthora infestans) and Improving Potato (Solanum tuberosum L.) Tuber Yield with Pre-Harvest Application of Calcium Nutrients

“…For instance, calcium nutrients suppressing the severity of Erwinia carotovora subsp. atroseptica of potato [12] and sweet cherries [13], stem rot of soybean [14], brown rot of peach [15], early blight of potato [16], and late blight of potato and tomato [16,17] has been reported. Similarly, Subhani et al [18] stated that higher calcium content in potato foliage resulted in more resistance of the plant against infection with late blight.…”

Genetic analysis and identification of DNA markers linked to a novel Phytophthora sojae resistance gene in the Japanese soybean cultivar Waseshiroge

“…Methods for managing economic losses to Phytophthora include fungicides (Anderson and Buzzell 1982), planting cultivars with race-specific or partial resistance (Dorrance et al 2003), soil drainage (Schmitthenner 1985), tillage practices (Workneh et al 1998), and calcium applications (Sugimoto et al 2005(Sugimoto et al , 2007(Sugimoto et al , 2008b(Sugimoto et al , 2009(Sugimoto et al , 2010. Schmitthenner (1999) reported that the most effective method to reduce damage would be to plant resistant cultivars, and genes conditioning resistance to P. sojae (Rps genes) have been widely used in commercial soybean cultivars for controlling Phytophthora stem and root rot disease (Dorrance and Schmitthenner 2000).…”

Fungicidal effect of some non-conventional chemicals for management of alternaria blight disease of mustard

“…The above results underline the importance of mineral nutrition as a component of disease management practices (Agrios, 2005;Hossain and Mian, 2005;Sugimoto et al, 2008;Meena et. al., 2011).…”

“…The extent of disease reduction was related to increased calcium uptake by plants, suggesting that calcium was the effective element in reducing phytophthora stem rot in soybean (Sugimoto et al, 2008).…”