Calotropis procera- a bioherbicidal agent to control barnyard grass and bermuda grass in paddy fields

Barnyard grass (Echinochloa crus-galli L.) and Bermuda grass (Cynodon dactylon L.) are the most prominent weeds in rice field which significantly affected the growth and development of rice from germination stage to yielding stage. The allelopathic effect of dry leaves (mature and senesced) aqueous extracts (5%, 10%, 15%, 20% and 25%) of Calotropis procera Decne., was investigated to evaluate the herbicidal efficacy on the germination and growth of Barnyard grass (Echinochloa crus-galli L.) and Bermuda grass (Cynodon dactylon L.). The results showed that the germination delayed when concentration increased from lower to the higher concentrations. The most affected seeds of the tested plants were Echinochloa crus-galli, i.e. up to 89%. Generally, the radical length was more sensitive than plumule length against aqueous concentration. C.dactylon showed minimum retardation effect when treated with C. procera aqueous extract. Aqueous mature leaves extract of C. procera showed maximum inhibited (upto 89%) at the higher concentrations (25%). C.dactylon shown stimulatory effect on its all physio-biochemical parameters, when treated with low concentrated (up to 5%) aqueous concentration of C.procera. The phytotoxic effect of matured leaves was more pronounced than senesced leaves.