balita, February 3, 2011 8:18 am

SCIENCE CITY OF MUNOZ, Nueva Ecija, Feb. 2 — The Philippine Rice Research Institute (PhilRice) is advising farmers to plant different rice varieties for the succeeding seasons as a way to maintain resistance against major crop diseases.

The PhilRice made the recommendation following findings that planting rice variety- NSIC Rc158- for two consecutive cropping seasons caused the occurrence of rice blast in Kabacan, North Cotabato.

Blast caused by the fungus Magnaporthe grisea injured rice plants in the area during its vegetative stage.
Frezzel Praise Tadle, PhilRice Midsayap monitoring team leader, said the successive planting of the same rice variety weakens resistance especially when the seed is disease-infected.

Blast, commonly known as "mata-mata" in Tagalog; "agupaw" (Waray); and "taya-taya" (Cebuano) could reduce yield by 50 to as much as 85 percent.

“Always use healthy seeds. Infected seeds from harvested plants should not be used for planting,” she said.
Tadle said the frequent rains experienced in North Cotabato since early this year intensified disease infections as rice blast survives in cooler weather.

High relative humidity and long-hour exposure to dew also favor disease development, she said.
“Fungus produces thousands of spores, which can be easily carried by the wind and infect other healthy plants,” she explained.

To minimize further damage to plants, PhilRice has recommended the following:
– Farm activities such as weeding and fertilizer application should be avoided when rice leaves are wet because spores scatter easily. Germination immediately occurs once spores land on wet leaves;
– Dense planting should also be avoided as this could easily transfer spores from one plant to another;
– Nitrogen fertilizer should be done in split application;
– Continuous flooding at all crop stages after transplanting should be practiced; and
– Fungicides such as benomyl, edifenphos, pyroquilon, tricyclazone, and isoprothiolane can be applied but this should be the last resort to manage rice blast. [(PNA)LAP/LAM/zst/MEG/ps]

Source: PhilRice advises farmers to plant different rice varieties to resist crop diseases