What would be Filipino dishes without eggplant (scientific name: Solanum melongena)? It is unthinkable not to have talong, as it is commonly called, in “pinakbet,” “torta,” “ensalada,” “sinigang” and “kare-kare.”
It is no wonder why eggplant is one of the leading vegetable crops in the country. Eggplant production covers approximately 22,000 hectares, yielding a volume of about 220,000 metric tons annually.
The popularity and profitability of eggplant among Filipinos has led to the emergence of the eggplant fruit and shoot borer (EFSB). “The emergence of EFSB as a major pest of eggplant was precipitated by a disregard of the basics of ecological diversity and balance,” wrote Dr. Asuncion K. Raymundo and Dr. Rita P. Laude in their paper on the impact of Bt talong on agricultural productivity and food security.
“At the outset, when this pest was (still negligible), it was ignored as the continuing cultivation of the crop, demanded by a growing market, afforded steadily income. In many eggplant-growing areas, ratooning of the crop, which provided almost uninterrupted host presence, exacerbated outbreaks.”
If there’s one pest that causes so much damage on eggplants, it’s the eggplant fruit and shoot borer (EFSB).
Today, the pest known in the science world as Leucinodes orbonalis is a major pest of eggplant in the country. EFSB feeds almost exclusively on eggplant. An entire crop can be lost from EFSB infestation. “The worm of the insect bore tunnels in the fruit, rendering them unfit for consumption,” said former Science Secretary Emil Q. Javier.
Drs. Raymundo and Laude reported that 51-73% of the crop is lost when any form of control is not provided. “This magnitude of loss has prompted the use of 60-80 pesticide sprays during the planting season,” the two authors wrote. “In extreme cases, unharvest eggplant fruits are dipped into a mixture of several chemicals to ensure higher yield.”
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. “Thus, in order to protect their crops, farmers spray their plants almost every other day with insecticides.”
Edgar C. Talasan, a vegetable farmer from barangay Imalutao in Impasug-ong, Bukidnon, said that in his 15 years of vegetable farming, 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.
There are also farmers who try not to use chemicals by doing any of the following: manual removal of infested shoots, crop rotation, intercropping, using nylon net barriers, trapping of the male using pheromones, applied either singly or in an integrated manner. These are, to quote the words of Dr. Raymundo and Laude, “typically labor-intensive and generally ineffective.”
One possible solution to the problem is to introduce “Bacillus thuringiensis” (Bt) into the vegetable crop. Thus, Bt talong came into existence. “Bt talong was developed by genetically engineering a gene from the bacteria so that the GM 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.
Bt, a common soil bacterium, produces a protein that paralyzes the larvae of some harmful insects, including EFSB. “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 International Service for the Acquisition of Agri-biotech Applications (ISAAA).
Bt is present in the Philippine soil and had been in use for years without any harmful effects. As it comes from the earth itself, Bt is very natural, according to Dr. Emiliana Bernardo, an entomologist or a scientist who studies insects. In 1901, Bt was discovered to have an insecticidal property. By 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 question is: Is the Bt protein found in Bt talong safe to non-target organisms? On tests conducted on dogs, guinea pigs, rats, fish, frogs, and even birds, the Bt protein was found not to have any harmful effects, according to Extension Toxicology Network (Extoxnet), a pesticide information project of several US universities.
“The specificity of Bt for its target insects is one of the characteristics that make it an ideal method of biological pest control,” the ISAAA briefing paper said. “The specificity rests on the fact that the toxicity of the Bt protein is receptor-mediated. This means that for an insect to be affected by the Bt protein, it must have specific receptor sites in its gut where the proteins can bind. Fortunately, humans and majority of beneficial insects do not have these receptors.”
According to Dr. Bernardo, cooking the Bt talong can completely denatured the Bt protein. “It is non-detectable in any cooked food therefore there is no human exposure to Bt proteins in eating cooked Bt crops,” she said.
Meanwhile, Dr. Javier said that “Bt eggplant is potentially the best environmentally friendly technology for eggplant production.”
Drs. Raymundo and Laude believe “the continuing use of Bt talong should provide a steady supply of a sufficient quantity of affordable and nutritious food for optimal nutrition. It makes available a healthy and safe source of food bereft of the lingering fear of insecticide poisoning.”
In India, Bt talong is already commercialized. In Bangladesh, the variant’s consumption has already been allowed.
Is the Philippines next in line?
