Department of Plant Pathology, CCS, Haryana Agricultural University, Hisar (Haryana)
National Symposium on “Plant Pathology in the Changing Global Scenario” held at National Bureau of Plant Genetic Resources, New Delhi on February 27–28, 2009
Rice (Oryza sativa L.) crop suffers from several diseases including sheath rot complex caused by Sarocladium oryzae (Sawada) Gams and Hawksworth and Fusarium moniliforme Sheld. The widespread occurrence of this disease has assumed an economic significance in recent past. With the introduction of high yielding and nitrogen responsive varieties and host genetic diversity greatly enhanced the severity of the disease. Durability of disease management through chemical sprays is likely to be inadequate to avoid losses under disease epiphytotic conditions. Therefore, an experiment was initiated to evaluate the efficacy of fungitoxicants, non-conventional chemicals and botanicals against the disease. Out of the five fungitoxicants tested under in vitro conditions, carbendazim (25 ppm) while propiconazole (100 ppm) completely inhibited the growth of S. oryzae. Carbendazim was most effective in inhibiting the fungal growth with EC50 value of 2.4ppm a.i. closely followed by propiconazole with EC50 value of 5.0 ppm a.i.. Among the neem products, Neemgold completely inhibited the growth of the pathogen at 100 ppm a.i. while Achook arrested the fungal growth completely at 200 ppm a.i. Neemgold was most inhibitory with EC50 value of 6.3 ppm a.i. closely followed by Achook with EC50 value of 12.6 ppm a.i.. Propiconazole in combination with either of the two neem products i.e. Achook and Neemgold resulted in higher gain in yield (16.7 and 16.0 q/ha, respectively) followed by combination of carbendazim with either of the neem products (14.6 and 13.9 q/ha respectively). Combination of propiconazole with Achook or Neemgold reduced disease incidence by 54.3 and 52.6 per cent, respectively. The two treatments also resulted in highest grain yield 59.8 and 59.1 q/ha respectively with corresponding increase of grain yield by 38.7 and 37.1 per cent, respectively over check. Zinc sulphate (0.15) among the six non conventional chemicals proved to be the most effective in reducing disease incidence and increasing grain yield. The maximum benefit: cost ratio of 10.3: 1 was obtained with two sprays of carbendazim alone followed by propiconazole alone (B:C ratio 9.3: 1).
