GMO brings back good insects in Philippine farms

Many of the "good guys" in the insect world are back in Philippine farms.

In corn fields, particularly.

Credit for this encouraging development goes mainly to genetically modified organisms (GMO), specifically the so-called Bt corn.

Bt stands for Bacillus thuringiensis, a bacterium that naturally occurs in soil.

Through biotechnology (genetic engineering) technique, a specific gene of Bt has been introduced or inserted in a corn variety. The Bt corn produces its natural pesticide against the Asian corn borer, one of the most destructive pests attacking corn in the Philippines and in other Asian countries.

Considering that a GM crop has a built-in defense mechanism against crop pests, it needs less pesticide.

Before the Bt corn’s introduction in Philippine farms about half a decade ago, farmers excessively used chemicals in controlling destructive insects that attacked their corn fields.

Distressingly, in the process, it was the "good guys" or beneficial insects that considerably succumbed to the toxic chemicals sprayed on them. The "bad guys" had often been the more resilient ones or survivors.

But now comes Bt corn and there is now less or minimal use of pesticides or insecticides to protect the corn plants from their attackers.

This has been confirmed by actual farmers themselves, among them Rosalie Ellasus, president of the Philippine Maize Federation (PhilMaize), which is composed of multipurpose cooperatives in the country’s corn-producing regions.

Ellasus, a successful corn farmer from San Jacinto, Pangasinan, detailed her encouraging and productive experiences with Bt corn at an international conference on biotechnology held recently at the InterContinental Manila Hotel in Makati City.

Billed "Biotech Issues and Communication Workshop Enhancing Communication Skills of Southeast Asian Decision Makers on Biotechnology," the conference was sponsored by the International Service for the Acquisition of Agri-biotech Applications (ISAAA) and the Los Baños-based, government-hosted Southeast Asian Regional Center for Graduate Study and Research in Agriculture (SEARCA) through the SEARCA Biotechnolgy Information Center (BIC).

Supported by the United States Grains Council (USGC), the science forum was attended by about 60 scientists, researchers, and communicators from the Philippines, Indonesia, Malaysia, Thailand, Vietnam, Singapore, the United States and Kenya.

In her report, Ellasus noted the increase in population of beneficial insects, notably spiders, on her farm.

Even dragonflies and fireflies can now be observed in Bt corn-planted fields, she said.

Ellasus echoed the similar observations of members of PhilMaize, a good number of whom are now planting genetically modified corn.

A gentleman-farmer from Pililia, Rizal, Edgardo Reyes, also told the conference participants of the proliferation of beneficial insects on his Bt corn farm.

The corn field of Reyes, an engineer, was among the farms and research and academic institutions visited by the participants in the biotechnology forum.

The testimonials of Ellasus, Reyes and members of PhilMaize boosted results of earlier studies conducted on the benefits of GM crops.

"More beneficial insects are found in Bt corn fields than in non-Bt corn fields sprayed with chemical insecticides," stressed Dr. Stephen Reyes of the University of the Philippines Los Baños-College of Agriculture (UPLB-CA).

Dr. Reyes studied the impact of Bt corn MON810-Yieldgard corn hybrid, DK818YG, on the variety and community of insects in farmers’ fields in Barangay Villaluna in Cauayan, Isabela and Panagan in Tigaon, Camarines Sur during the 2001-2002 wet cropping season.

"A corn field is a dynamic community where different groups of insects live together," the UPLB scientist explained.

The phytophagous (those that feed on the different parts of the corn plant) had the most number. This group includes Asian corn borer, cutworms, corn silk beetles, earworms, mired bugs, locusts, aphids, leafhoppers and planthoppers.

"Corn silk beetles were very abundant at the Tigaon site during silking (flowering), while the migratory locusts were numerous at the Villaluna site," Dr. Reyes reported.

The Bt corn fields were least infested with corn silk bettles, he added.

The next abundant group were the neutrals, followed by the predatory and parasitoid species.

The neutral species include midges, mosquitoes, and Sarcophaga species.

The predatory insects found were the green lacewing, brown lacewing, and coccinellid beetles.

Parasitoids are insects that eat or parasitize the eggs of other insects. The dominant species of egg parasitoid is Trichogramma evanescens Westwood noted in Isabela.

"Natural enemies like the predatory insects and parasitoids are important because they reduce the population of insect pest species," Dr. Reyes said. "Presently, Yieldgard (Bt corn) does not appear to have a harmful effects on insect diversity, guild structure, and abundance of natural enemies."

Another study done by UPLB researchers Dr. Jose Yorobe Jr., Cesar Quicoy, Edwin Alcantara, and Blanda Sumayao detailed the experiences of farmers attesting benefits of using Bt corn such as resistance to corn borer and high yield.

The study, titled "Impact Assessment of Bt Corn in the Philippines," was done during the wet and dry seasons of crop year 2003-2004 in four major corn-producing provinces: Isabela, Camarines Sur, Bukidnon, and South Cotabato.

Other advantages of Bt corn cited by the farmers were low expenditure on pesticides and high premium price of Bt corn in the market owing to better quality and less impurities.

Another report authored by four scientists – Dr. Reynaldo Ebora, Amparo Ampil, Merle Palacpac, and Carlo Custodio Jr. – concluded:

"Farmers reported that Bt corn technology gave them higher yield with high quality grains. They also reported needing less pesticide or none at all, as expected since Bt corn is resistant to corn borers. In general, Bt corn farmers were able to reap good quality crop during harvest."