The profitability of planting transgenic eggplants

Published February 3, 2023, 5:00 PM

by Manila Bulletin Agriculture

Eggplants are among the vegetables being sold in the market (Henrylito D. Tacio)

By Henrylito D. Tacio

The eggplant is used in various cuisines around the world. It can be sliced, battered, and deep-fried, and then served with various sauces.  It can also be stuffed with meat, rice, or other fillings and then baked. In the Philippines, eggplant is one of the main ingredients of pinakbet, torta, sinigang, ensalada, and kare-kare.   

The popularity of eggplant is the reason why it is the number one vegetable in the country – in terms of area planted (20,000 hectares) and volume of production (179,000 metric tons).  Most of the top producing regions are located in Luzon like Ilocos, Central Luzon, Cagayan Valley, CALABARZON (composed of Cavite, Laguna, Batangas, Rizal, and Quezon) and Bicol.

Resource-poor farmers in many provinces grow eggplant and depend on it for their livelihood. One of them is Edgar C. Talasan, a vegetable farmer from barangay Imalutao in Impasug-ong, Bukidnon. At one time, he planted 2,500 eggplants in his farm. In just one crop cycle, he got a gross income of P84,000. 

From the income of his farm, he was able to raise his family well. In fact, he sent his daughter through college by selling the vegetables harvested from his farm. “I was happy and content in my little kingdom,” he said.

But what makes him sad is the fact that eggplant production in the country suffers a severe yield loss from insect pests, diseases and extreme environmental conditions. In a technology forum he attended in Pangasinan, he realized that eggplant growers sprayed their crops with chemicals once a day to protect the eggplants from infestation. 

Destructive eggplant pest

The most destructive insect pest that attacks the crop is called the eggplant fruit and shoot borer (EFSB). Scientifically, it is called Leucinodes orbonalis, a moth species prevalent in Asia and Africa. The moths’ larvae feed on eggplant shoots and fruits until maturity. 

How EFSB destroys an eggplant. Picture taken from a lecture (Henrylito D. Tacio)

“The EFSB can cause as much as 50-75 percent loss of fruits,” said former Science Secretary Emil Q. Javier. “The worm of the insect bore tunnels in the fruit, rendering them unfit for consumption.”

Unfortunately, there is no known genetic resistance to EFSB in cultivated and wild eggplants.  “The insects are concealed in the shoots and fruits and are difficult to reach,” Dr. Javier explained. 

To reduce the population of EFSB, some farmers practice integrated pest management, which include: regular crop rotation, or intercropping eggplant with other vegetables; removal and burying of infested and damaged shoots and fruits; and using nylon net barriers to protect plants from the insects. 

Other farmers employ the following: using light or pheromone traps; growing eggplants in a screen house before transplanting in their farms; and conservation of beneficial arthropods (spiders, parasitoids, and predators). 

Using pesticides 



But there are farmers who spray their eggplants almost every other day with insecticides to protect the crops. 

In his 15 years of vegetable farming, Talasan said that in every eggplant cropping cycle, he sprayed at least twice a week. For every 1,000 eggplant hills, he used 0.5 kilogram of Lannate, two bottles (250 mL) of Prevathon, two bottles (250 mL) of Alika, one liter of Karate, one kilogram of Daconil, and 0.5 liter of Selecron. 

The current method of spraying chemicals to eggplants in order to control EFSB is unacceptable, according to Dr. Emiliana Bernardo, an entomologist or a scientist who studies insects. 

The practice is also unhealthy to consumers, farmers, and the environment, said Dr. Bernardo, who is also a member of the Institutional Biosafety Committee of the University of the Philippines Los Baños.

She said studies conducted in major eggplant producing provinces found that almost all farmers use chemical insecticides and that some even dip the unharvested eggplant fruits in a mix of chemicals just to ensure that harvests are marketable. 

“The very basic question is, which is safer, the present practice or the alternative, the Bt eggplant which is rigorously evaluated by experts?” she asked. “Is bathing the unharvested eggplant fruits in chemicals, which would end up in people’s dinner tables, safe?” 

Bt eggplant

 Are there other ways of controlling EFSB?  Scientists who tried various methods came up with Bt eggplant, a genetically modified (GM) crop. Bt stands for Bacillus thuringiensis

Bt eggplant (Biotech Infocenter of the Southeast Asian Regional Center for Graduate Study and Research in Agriculture

 “Bt talong was developed by genetically engineering a gene from the bacteria so that the genetically modified eggplants now produce a protein that defends it against insect attacks,” explained Dr. Michael Purugganan, a Filipino plant geneticist who is the Dean of Science at the New York University.

“When ingested by the larvae of the target insect, the Bt protein is activated in the gut’s alkaline condition and punctures the mid-gut leaving the insect unable to eat. The insect dies within a few days,” noted a briefing paper circulated by the Laguna-based International Service for the Acquisition of Agri-biotech Applications (ISAAA). 

Conventional eggplant vs Bt eggplant. (Biotech Infocenter of the Southeast Asian Regional Center for Graduate Study and Research in Agriculture)

Bt is present in the Philippine soil and has been in use for years without any harmful effects. As it comes from the earth itself, Bt is very natural, according to Dr. Bernardo. In 1901, Bt was discovered to have an insecticidal property. By the 1950s, it became a well-known biological insecticide. 

Bt is easily cultured by fermentation,” the ISAAA briefing paper said. “Thus, over the last 40 years, Bt has been used as an insecticide by farmers worldwide. Organic farming has benefited from Bt insecticide, as it is one of the very few pesticides permitted by organic standards. The insecticide is applied either as a spray or as ground applications. It comes in both granules and liquefied form.”

The first Bt eggplant was developed by the Indian Maharashtra Hybrid Seeds Company Limited (Mahyco).  The Institute of Plant Breeding at the University of the Philippines at Los Baños (UPLB) has developed the Bt eggplant in the country, in partnership with Mahyco and Cornell University and with support from the United States Agency for International Development (USAID). 

The ISAAA says that before Bt eggplant is approved for commercial use, scientists and regulators ensure that it passes through many tests and safety assessments.  In the Philippines, the biosafety of Bt crops is evaluated by a pool of technical scientists in five stages: contained research in laboratories and screen houses; small limited confined field trials; multi-location field trials; food, feed and processing; and commercial propagation. 

Approved for propagation 

In July 2021, the Bureau of Plant Industry (BPI) – a line agency of the Department of Agriculture – approved Bt eggplant for direct use as food, feed and for processing (FFP).  In issuing Biosafety Permit No. 21-078FFP, it is found “to be safe as conventional eggplant” and “can substitute for its traditional counterpart.” 

A year later, on October 18, 2022, the government approved Bt eggplant as the third genetically engineered crop for commercial propagation, following Bt corn and golden rice (now known as Malusog rice).  

Bt eggplant’s approved followed regulatory procedures as detailed in the revised Joint Department Circular, which showed proof of the country’s commitment to science and improvements in biotechnology. 

Vegetable farmers need not to worry when it comes to planting eggplant.  “There are no differences in the production practices (fertilizer application, weeding, irrigation) used in growing of Bt eggplant compared to conventional eggplant except in insecticide application against the borer,” said Dr. Lourdes D. Taylo, study leader of the Bt eggplant project from UPLB. 

Dr. Lourdes D. Taylo, the study leader of the Bt eggplant project from University of the Philippines at Los Banos Henrylito D. Tacio)

Economic and health benefits

A recent study showed that Bt eggplant could bring health cost savings of P9.33 million yearly from its nearly pesticide-free use. Researcher Sergio R. Francisco has estimated savings in a survey of long exposure to pesticide spraying against the highly-infested EFSB in his study, “Health and Environmental Impacts of Bt Eggplant.” 

The study was based on the perception of 100 eggplant farmers from Batangas, Nueva Ecija, Pangasinan, and Quezon who sprayed their eggplant. These farmers have a long experience in farming – from 9.96 to 18.04 years. 

Another study showed that a Bt eggplant farmer gets P50,330.00 net income for every P100,000.00 gross sales. In comparison, a net income of P16,880.00 is all a farmer gets who plant conventional varieties. 

In a press statement, it was disclosed that the benefit to human health from health cost savings in growing Bt eggplant is equivalent to P2.49 million yearly as risk from illnesses is avoided. For farm animals, the projected benefit per year is at P2.12 million. 

For beneficial insects, the environmental benefit is valued at P2.45 million yearly and for bird species, P2.27 million – as these are saved from death, thereby contributing to biodiversity enhancement.  

Are Bt crops like Bt eggplant safe to eat? The GM Science Review Panel of the United Kingdom has this to say: “For human health, to date there is no evidence currently commercialized GM crop varieties or foods made from them, are toxic, allergenic or nutritionally deleterious.  On balance, we conclude that the risks to human health are very low for GM crops currently on the market.” 

The Geneva-based World Health Organization also assured: “The potential direct health effects of GM foods are generally comparable to the known risks associated with conventional foods, and include, for example, the potential for allergenicity and toxicity of components present, and the nutritional quality and microbiological safety of the food.”

Eggplant salad. One of the most popular ways of preparing eggplant for table. (Henrylito D. Tacio)

Photos by Henrylito D. Tacio
Additional photos by SEARCA