Evaluation of natural products for the management of damping-off of tomato incited byPythium aphanidermatum(Edson) fitz

Abstract

The effect of various natural products from plants and animals were evaluated for the presence of antifungal activity against Pythium aphanidermatum causing damping-off of tomato. Among the plant species tested, bulbs of A. sativum (10%) and Allium cepa var. aggregatum (20%), leaves of Lawsonia inermis, Piper betle (20% each), Eucalyptus globulus and Vitex negundo (40% each) exhibited complete inhibition of the mycelial growth of P. aphanidermatum. Out of 4 animal excreta screened, Pig dung (40%) extract totally inhibited the mycelial growth of P. aphanidermatum. Garlic bulb, eucalyptus leaf and hen litter extract were found to retain the fungitoxicity when extracted at 80 °C for 10 minutes. A. sativum bulb followed by E. globulus leaf extracted in acetone was found to be significantly superior over other natural products. Among the natural products tested, the minimum mycelial dry weight of P. aphanidermatum was obtained with garlic bulb followed by eucalyptus leaf extract. The plant products combined together retained strong inhibitory effect in solid and liquid media against P. aphanidermatum. Upon mixing, the more loss of toxicity was observed when botanicals were mixed with animal excreta, particularly with pig dung. Among the natural products tested, the water extracts of A. sativum plus E. globulus and A. sativum plus L. inermis combinations recorded the maximum percentage of seed germination, growth and vigour of tomato seedlings, respectively. Also, when the various natural products tested by seed treatment, soil drenching and seed treatment plus soil drenching, garlic plus eucalyptus treatment recorded maximum seedling emergence and lesser damping off incidence in all three methods of application. Among the three methods, seed treatment plus soil drenching (St+Sd) was found to be superior than other two methods.