Farmers in Isabela, Pangasinan, and Cagayan, three of the largest users of the genetically modified (GM) borer-resistant corn have enjoyed an average yield advantage of 15.23 percent, less spray, and higher income from GM corn in the past three years, a survey said.

A Biotechnology Coalition of the Philippines (BCP) survey indicated that 74 percent of a survey group or 687 out of the total 895 surveyed users of the GM Bacillus thuringiensis (Bt) corn claimed to be satisfied with the technology.

This shows that an average of 15.23 percent increase in harvest over non-Bt corn was observed in yield in the dry season and an average of 13.39 percent yield advantage in the wet season. Aside from increased yield, top considerations of Bt corn users in using the technology are protection from the pest corn borer, absence of need for pesticides and chemicals, and savings from cost-efficiency of the product, according to Godfrey B. Ramon of BCP.

Savings on time as labor is reduced for pest management, higher selling price for the cleaner corn (without pest marks), and longer storage life for corn are other reasons for farmers' use of Bt corn.

Wilma R. Cuaterno, Bureau of Plant Industry Crop Protection Chief, said in a separate report that a total of 122,821 hectares were planted to Bt corn in the Philippines from 2003 to 2005 of which the majority of 102, 739 hectares were in Luzon, 19,011 hectares in Mindanao and 1,071 in Visayas.

The first three adopters of the technology were Isabela which had 34, 216 hectares planted on Bt corn for the period; Pangasinan, 23, 517 hectares; and Cagayan, 10, 892 hectares.

In Mindanao, top users of Bt corn were South Cotabato, 5, 013 hectares; Sultan Kudarat, 4, 921 hectares; and North Cotabato, 2, 586 hectares. Users in Visayas were Iloilo, 400 hectares; Capiz, 361 hectares; and Cebu, 168 hectares.

Ramon is concerned that to maximize propagation of the borer-resistant corn, government should look into the possibility of making the technology more affordable to farmers since Bt corn price at about P 5,000 per bag is about two times the cost of plain hybrid corn seeds.

While monitoring farmers' benefit from the technology that faced opposition from various groups who fear its harm to human health and environment, government is looking at ways to improve farmers' adoption of an integrated crop management (ICM) that will ensure that the pests will not develop immunity from Bt corn in the future.

Pest die upon eating Bt corn as this corn has been injected with the [protein gene that kills the Asiatic corn borer (ACBs). But scientists accept the fact that ACBs can eventually develop immunity from Bt corn, the only question is the length of time that may involve.

The US experience over the last years on the use of Bt corn has not so far indicated any immunity that ACB could have already developed against Bt corn.

This ICM involves the allocation of a 20 percent non-Bt corn farm area in a minimum of 200 hectares of contiguous area so that pests will continue to mate with pests that eat non-Bt corn and thus delay the pests' immunity to Bt corn.