Farmers in regions two and three have reported a moderate incidence of blast disease in their fields, a press release from the Guyana Rice Development Board (GRDB) said yesterday.
The GRDB said farmers, particularly those cultivating the rustic line have found evidence of the disease on their farms. It said too the disease is normally prevalent in the second growing season (second crop) and its severity increases with distance from the tidal flat. Areas three to five miles from the tidal flat or river bank are vulnerable to the disease “because of the high relative humidity and lack of air movement.”
Plants affected by the disease will have lesions or spots on the leaf blade or necrotic areas on the borders of older leaves. It may also affect the panicle – defined by an online dictionary as “any loose, diversely branching flower cluster” – by developing necrotic areas at its base which may result in no grain set or may cause only the upper section of the panicle to produce normal grains, depending on the time the disease occurred.
The GRDB said too high nitrogen (urea) application rates, high relative humidity, high plant density; prolonged overcast conditions along with frequent drizzles or dew are all factors that contribute to the onset and severity of the disease.
Control measures include using resistant varieties especially during the second growing season as rustic is susceptible to the blast disease organism. Farmers can also avoid high plant density (seed rate) and avoid quantities of nitrogen (urea) application in a single dose on susceptible varieties. The GRDB said chemicals (fungicides) are also available that can provide acceptable control of blast disease.
When using Carbendazin farmers should use 148 to 296 mls/ha (60 to 120 mls/ac) in 10 gallons of solution /ha (4.0 gallons of solution/ac) and apply with a mist blower. For Amistar use 250 to 300g/ha (101 to 121 g/ac) in 10 gallons of solution and apply with a mist blower. If available the GRDB said 500 to 750 mls/ha (200 to 300 mls/ac) Fungi-one can be used in 10 gallons of solution ha/ac. Apply with a mist blower.
