Bio Efficacy of Different Non-Hazardous Alternative Chemicals and Commercial Fungicides for Controlling Groundnut Stem Rot by Sclerotium rolfsii. S

Abstract

In Sri Lanka groundnut (Arachis hypogaea L) is grown mainly for edible purposes and it’s mostly affected by stem rot disease that is caused by the necrotrophic soil-borne plant pathogen Sclerotium rolfsii. To control stem rot disease, farmers generally use commercial fungicides that lead to developing resistance forms of S. rolfsii. The present study was conducted to identify environmentally sound nonhazardous alternative chemical products to control S. rolfsii. Two non-hazardous alternative chemicals (Na2CO3 (T6) and NaHCO3 (T7)) are investigated with five commercially available fungicides (Captan (T2), Carbendazim (T3), Mancozeb (T4), Chlorothalonil (T5), and Sulfur (T8)) with different concentrations under In-vivo and In-vitro conditions. The field experiment was laid out in a Randomized Complete Block Design on eight treatments with three replicates for two different concentrations (500ppm and 1000 ppm). The In-vitro experiment was laid out in Complete Randomized Design on eight treatments with five replicates for two different concentrations (500ppm and 1000 ppm). In the In-vitro conditions, the mycelial growth inhabitation rate was measured. From the mycelial growth inhibition, T6 (Na2CO3) and T7 (NaHCO3) successfully inhibited mycelial growth like commercially available fungicides at 1000 ppm (T6-100% and T7-100%). In 500ppm concentration, the complete inhibition rate (no mycelial growth) was observed in T6 (Na2CO3). In In-vivo, the disease incidence was recorded. From that results, there is no significant difference between commercial fungicides and non-hazardous alternative chemicals (Na2CO3 and NaHCO3) in both concentrations (500 ppm and 1000 ppm). Therefore the non-hazardous alternative chemicals (sodium carbonate and sodium bicarbonate) were equal and superior to the other fungicides for control of S.rolfsii on groundnut in 500ppm and 1000ppm concentrations.