Activation of defense mechanism in Lehsua (Cordia myxa) through systemic acquired resistance inducers against Alternaria leaf spot disease

Abstract

Indian cherry or Lehsua (Cordia myxa Roxb.) is vernacularly known as Lasoda and Gunda and it is a major fruit of the family Boraginaceae which well flourished in arid conditions of Rajasthan and India. The immature fruits are used for preparing mix vegetable and pickle in Indian cuisine. Alternaria leaf spot of lehsua, caused by Alternaria alternata is an important disease of this crop and causes economic yield loss. In present investigation, four systemic acquired resistance (SAR) activators (salicylic acid, isonicotinic acid, hydrogen peroxide and β-amino butyric acid) were sprayed in orchard and this was the foremost case of study in perennial and arid fruit crops in Rajasthan. Among these, spray of salicylic acid (@200 ppm) proved most effective in reducing disease intensity (54.87%) followed by 2,6-dichloroisonicotinic acid (47.85%) possibly by activating the cellular genes and defense mechanism and thereby spreading throughout the plant body. These SAR inducers can be used as an alternative to fungicides as green chemicals by incorporating in integrated disease management system, because they do not cause bio-accumulation in eatables and environmental hazards.