MANILA, Oct 9 - Annual growth in Philippine rice output in the July to September quarter will likely be below 6 percent due to the high cost of fertilisers, the agriculture chief said on Thursday.

"I do not see 6 percent growth in the third quarter," Agriculture Secretary Arthur Yap told reporters.Official farm output data for the third quarter is expected to be released around the middle of November.

Agriculture products, including rice, corn, tropical fruits and fish, account for about a fifth of the Southeast Asian nation's gross domestic product, but output this year is expected to be hit by high costs.

"The prices of fuel are dropping but not fast enough to translate to a drop in fertiliser prices," Yap said.

He said there has been a 30 percent drop in fertiliser sales and this would impact harvests in the second half and into early 2009.

Farm output grew 5.4 percent in the second quarter from a year earlier, outpacing the 3.9 percent annual rise in January-March. But that only brought annual first-half growth to 4.7 percent, at the lower end of the government's target range for the year of 4.5-5.5 percent. Yap said there was no plan yet to revise the full-year growth target.