Agrotechnology

Evaluation of selected fungicides against rice false smut disease

3^rd International Conference on Agriculture & Horticulture

October 27-29, 2014 Hyderabad International Convention Centre, India

D Ladhalakshmi, G S Laha, D Krishnaveni, V Prakasam and M S Prasad

Accepted Abstracts: Agrotechnol

Abstract:

False smut disease caused by Ustilaginoidea virens (Cooke) (Takahashi) is a grain disease of rice. U. virens convert whole grain into powder (smut balls) form. Its believed that the pathogen infects during heading to flowering stage of the crop. Pathogen infection leads to sterile spikelets and reduction in 1000 grain weight. Earlier, the disease had been categorized as a minor disease due to its sporadic occurrence. However in recent years it has been emerged as the most devastating grain disease in majority of the rice growing areas of India due to cultivation of high fertilizer responsive cultivars and hybrids, heavy application of nitrogenous fertilizer and apparent change in climate. In severe cases the number of infected grains reached even more than 100 per panicle. Since the disease causes direct economic loss to the farmers, development of suitable management practices using effective fungicides are imperative. Three chemicals viz., trifloxystrobin 25%+ tebuconazole 50% (Nativo 75WG), kresoxim methyl (Ergon 44.3 SC) and propiconazole 25 EC (Tilt or Result) were evaluated both under in vitro and in vivo. Under laboratory conditions, all the three fungicides showed variable response in inhibiting the growth of the pathogen. Among the three fungicides, Nativo 75 WG (0.02 %, 0.04%, 0.06% concentrations) and Tilt (0.05%, 1.0% and 1.5% concentrations) inhibited the fungal growth up to 100 per cent. Similarly, same fungicides were evaluated under field conditions at different stages of the crop. Application of trifloxystrobin 25% + tebuconazole 50% (0.4g/l) or propiconazole 25 EC (1ml/l) either at 50 % or 100% panicle emergence stage was effective and both the chemicals were on par in their performance in reducing the percentage of infected panicles/m2 and infected spikelets/panicles and increasing the yield when compared to control.