Farmers planting the genetically-engineered Bt corn are sking seed producers to make planting materials more affordable.

A study by the Biotechnology Coalition of the Philippines (BCP) show that while more corn farmers are adopting Bt corn since its commercial release in 2002, majority still find planting materials very expensive.

"There is clearly a need to reduce the cost of Bt corn seeds to ensure the momentum is sustained," noted BCP in its study. Farmer-respondents to the BCP study conducted last year said that with rising production inputs, they may be forced to stop planting Bt corn and shift to other high value commercial crops with lower production costs.

Bt corn seeds are currently sold at P 4,400 to P 4,900 per 18-kilogram bag, about twice the price of hybrid corn seeds that are not induced with the Bacillus thuringiensis or Bt, which makes plants resistant to pest - particularly the Asian corn borer.

The BCP recommended that seed producers could consider measures to make their product cheaper through innovative finance, marketing and credit schemes not only to attract non-adoptors but also to maintain the high percentage of repeat users.

About 11 percent of those who plan to plant Bt corn in the future may decide otherwise, because of high cost of seeds, according to the survey.

Farmers who tried planting Bt corn were generally satisfied with their use of Bt corn because of the protection from corn borer, increased productivity, and less spraying of insecticide while those who are not complained about the cost of seeds and vulnerability to pest other than corn borer, diseases and natural calamities.

The survey revealed that Bt corn farmers, average yields were 13 percent higher than those planting regular corn hybrid seeds. Bt corn farmers generally produce 5.1 metric tons (MT) per hectare during dry seasons, and 4.9 MT per hectare during the wet seasons, which are 15.3 percent and 13.3 percent higher, respectively than those of non-adoptors, the survey revealed.

The use of Bt corn is on the uptrend as the country strives to attain self-sufficiency in corn. Last year, the Bureau of Plant Industry (BPI) approved for commercial production, the fourth biotech corn variety known as "stacked-trait corn" or Mon810/NK developed by Monsanto Philippines.

The stacked-trait corn is a superior variety, according to BPI, since it is both resistant to insects while tolerant with herbicides. Through genetic engineering, the company introduced the Bt gene that enables the corn plant to resist the attacks of Asiatic corn borer, a dreaded insect pest that can cause as much as 80 percent yield reduction.

This latest corn variety also combines the traits of two earlier approved biotech corn varieties developed by Monsanto - the Round-up Ready corn and Bt corn. In 2002, the Philippines approved Bt corn Mon 810. This gene is incorporated into the different commercial local corn varieties of Monsanto and Pioneer Hi-bred Philippines.

Locally, the Monsanto Bt corn hybrids are known as Dekalb (DK) 818YG, DK916YG, and DK9051YG. On the other hand, the local Bt corn hybrids are sold as 30Y84, 30Y50, 30Y80, 30Y73, and 30Y34.

In 2005, BPI also approved the Bt 11 of Syngenta Philippines.

Since commercial planting of Bt corn in 2003, there are now estimated aggregate areas of more than 100,000 hectares planted to insect-protected corn.