Incidence and severity of leaf spot and anthracnose diseases of Rauwolfia serpentina (L.) Benth. ex Kurz

Abstract

Rauwolfia serpentina (L.) Benth. ex Kurz is a medicinal plant. The plant is locally known as “Sarpagandha” also known as Indian snakeroot. During the tenure of 2007 to 2013 two types of symptoms viz. leaf spot and anthracnose were recorded from leaves of R. serpentina. Leaf spot disease incidence was started from February and gradually increased up to July. Leaf spot symptom showed lowest disease severity (1) in the month of February and the highest DS was (9) in the month of July. Whereas anthracnose disease incidence was started from March and gradually increased up to September. In case of anthracnose symptom, the lowest disease severity (2) was recorded in the month of March and the highest DS (9) was recorded in the month of September. Temperature shows noticeable effect on disease development. Rainfall and humidity also show slight effect on disease development. The fungi associated with the collected samples were isolated following „Tissue planting‟ method on PDA (Potato Dextrose Agar) medium and „Blotter method‟ Pathogenecity test of the isolated fungi were done following „Detached leaf technique‟ and „Spraying of spore suspension‟ on healthy plants. Among the isolated fungi Colletotrichum gloeosporioides was found to be pathogenic to R. serpentina.