Evaluation of environmental factors for optimum growth of Rhizoctonia solani causing root rot of cluster bean (Cyamopsis tetragonoloba)

Abstract

Clusterbean [Cyamopsis tetragonoloba L.) Taub.] is popularly known as "Guar" or "Guwar" and belongs to family Fabaceae of kingdom Plantae. It is an important legume crop and mainly grown under rainfed conditions of arid and semi arid regions of tropical India during Kharif and Zaid seasons. It is tolerant to drought, deep rooted and can be grown for different purposes viz., vegetable, green fodder, green manuring, production of seed and for endospermic gum (30-35 percent). Root rot caused by Rhizoctonia solani is an important and becoming severe problem of clusterbean in Rajasthan as well as India under the changing scenario of climate. This study was undertaken to find the most favorable and critical point of temperature, relative humidity and pH factors for optimum growth of the Rhizoctonia solani that may help in survival, spread and cause infection in healthy hosts. The most favorable temperature for flourishing and mycotic growth of Rhizoctonia solani was 30 0 C (90.00 mm) followed by 25 0 C (80.25 mm). Among various level of relative humidity, 90 per cent relative humidity was most favorable for maximizing growth (90.00 mm) while 6.5 pH was highly suited for maximum growth of the pathogen (632 mg dry mycelial weight). Conclusively, this pathogen requires higher temperature for fast multiplication that is prevalent in arid region of Rajasthan and due to these favorable factors this disease may be gaining importance day by day.

A Review on the Management of Country Bean (<em>Lablab purpureus</em> L.) Diseases in Bangladesh

“…Another major concern on common bean production in India is White mold triggered by Sclerotinia sclerotiorum (Chauhan et al, 2020;Heffer and Johnson 2007;Prajapati and Narain, 2008).Web blight is caused by Rhizoctonia solani that was reported to cause yield loss of Urdbean about 20-30% (Kumar et al, 2018). Rhizoctonia solani can also cause root rot of cluster bean (Shivran et al, 2020). In Mysore District of Karnataka State, India, Bean common mosaic virus Infecting Lablab purpureus has been seen for the first time (Udayashankar et al, 2011).…”