The Agriculture Department has advised farmers to be on the guard against incidence of rice blast, a fungal disease, in the standing paddy crop given the prevailing weather after the monsoon rain.
“Though there was no incidence of the disease so far in the district, the paddy crop would be susceptible to the disease under present climatic conditions. It can occur in fine grain type varieties such as BPT-5204 (Samba mahsuri) and improved white ponni. It will be prudent for farmers to be on the guard,” a senior official of the department told The Hindu .
A few years ago, the disease caused extensive damages and heavy losses to farmers in the district. Since then, the Agriculture Department has been dissuading farmers against opting for BPT-5204.
Advisories
Even though the department had been issuing advisories to farmers suggesting alternative varieties such as TKM-13, a large number of farmers continue to raise the variety as it is in good demand among traders and reportedly fetches a better price than others. This year too, several farmers have gone for the variety, the official said.
Samba paddy has been raised on about 43,500 hectares, both in canal irrigated and rain-fed areas in Tiruchi district so far. The area under cultivation is expected to increase in the rain-fed areas by the end of this month.
Application of excessive doses of nitrogenous fertilizers, intermittent drizzles, cloudy weather, high relative, long dew periods, and low night temperature could make the crop susceptible to the disease. The disease is caused by Pyricularia oryzae fungus which attacks the rice crop at all stages right from the seedlings in nursery. The symptoms can be seen on leaves, nodes, neck of panicle, and on grains.
Symptoms
Lesions start as small water soaked bluish green flecks on the leaves, soon enlarge and form characteristic spindle shaped or eye shaped spots with grey centre and dark brown margins.
The elongated spots join together as the disease progresses and large areas of the leaves dry up and wither. Similar spots form on the sheath. Blast infected grains become poorly filled and chaffy. Dark spots may be formed on the grains and reduces the grain quality.
If symptoms of the disease are found, farmers should remove and destroy the weed hosts. Farmers should spray (using handspray) 400 grams of pseudomonas fluorescens, mixed in 200 litres of water, an acre from the 45th day of the crop. This could be done thrice at 10 day intervals, the official said.
