Diseases of Rauvolfia Serpentina and their Biocontrol

Abstract

Disease survey were conducted at Jabalpur, Bhopal, (Madhya Pradesh), Raipur, Bilaspur (Chhatisgarh.), revealed that R. serpentina suffered from leaf spot diseases caused by Mycosphaerella rauvolfiae, Cercospora rauvolfiae, Phoma jolyana, Cladosporium oxysporum, Macrophomina phaseolina, Alternaria alternata, A. tenuis, A. tenuissima. The inflorescence disease caused by Colletotrichun dematium cause heavy loss in seed production. Top dying caused by Lasiodiplodia theobromae and wilt disease caused by Fusarium oxysporum f. sp. ruavolfiae the fungus infects plants through the roots and invades the water conducting tissues of the plant and causing damage to the plant. Twig blight caused by Corynespora cassicola. Due to above diseases of leaves, inflorescence, roots and twigs led to premature drying, defoliation and death of the entire plant. For the management of above diseases laboratory and field experiments were performed. Laboratory experiments were conducted with biocontrolling agents (Bacillus firmus, B. amyloliquefaciens, Streptomyces sp.), cow urine and biopesticide (1 lit cow urine + 100 g fresh leaves each of Azadiracta indica, Ailanthus excelsa and Calotropis procera) to evaluate the best treatment for some of the major pathogens. On the basis of laboratory study foliar spraying in the field were conducted. The results showed that among all treatments Bavistin 0.05% + Streptomyces sp. (106 spores/ ml) showed less disease intensity as well as better seed yield, followed by Bavistin 0.05% + Trichoderma harzianum (106 spores/ml), Bavistin 0.05% and plant tonic (25 ml in 1000 ml). It is concluded that foliar application of Bavistin 0.05% + Streptomyces sp. (106 spores/ml), Bavistin 0.05% + T. harzianum (106 spores/ml), and Bavistin0.05% alone proved effective in protecting leaf spot and inflorescence diseases and increasing of seed production.