In an article from the UP MPRO, PGC Program Director for Agriculture, Livestock, Fisheries, and Forestry Dr. Ma. Anita M. Bautista is featured as a transcriptomics expert at the UP NIMBB and PGC.

By Andre DP Encarnacion, UP MPRO

More than a century ago, a scientist named A.L. Melander wrote an article in the Journal of Economic Entomology on a disturbing turn of events in his native Washington. The year was 1914, and then, as now, farmers and entomologists were locked in combat with pests like the San Jose scale—an insect similar to the cocolisap that would nearly overwhelm the Philippine coconut industry a hundred years later.

Since its introduction in the US in the 1870s, the scale had been responsible for eliminating thousands of acres of apple trees. The frontline chemical to control it back then was sulphur-lime, an insecticide made by reacting calcium hydroxide with sulphur. Melander himself described the mixture as “fast acting” in its lethal effects. After years of success, however, to his great shock, Melander found that the insects were going against script. Some of the scales just refused to die.

More specifically, in samples taken from two Washington cities, he found that while insects from Wenatchee that he sprayed all died within a week, while 90% of the scales from Washington’s Clarkston Valley that he treated remained alive. Remarkably, even after Melander increased the active ingredient by ten times, 74% of the latter still survived.

Melander’s recounting of this phenomenon would become the first article ever to document insecticide resistance. For many, it was an ecological alarm bell. Researchers would eventually confirm that insect pests like the scale could take advantage of the laws of natural selection to better withstand insecticides over generations through metabolic or behavioural adaptations.

Dr. Maria Anita Bautista in the laboratory. (Photo by El Bacani, UP MPRO)

Against such a fast-adapting problem, it is up to scientists and farmers to update their own toolkits. For years, UP entomologist Dr. Ma. Anita “Marianne” Bautista has worked hard to do just that. And now as the head of the Philippine Genome Center’s (PGC) Agriculture, Livestock, Fisheries and Forestry Program, she’s spending her time trying to help others.

Lucky charm

Eventually, with complementary advances in genetics and genomics, scientists began to look into the molecular basis of insecticide resistance. While Melander went into the textbooks for his work on the San Jose scale, Bautista, too, has done considerable work on an insect pest she considers her “lucky charm”—the diamondback moth (Plutella xylostela L.).

The UP Los Baños graduate of BS Agriculture, major in Entomology, first started working with the moth as part of her thesis. Even before doing the genomics work that would become her trademark, she was already deeply interested in controlling its numbers. “Because it is a pest,” she says. “Your cabbage, your kale, your pechay—it is a notorious pest of those crops.”

Diamondback moth (DBM) larvae grown on cabbage seedlings for insecticide resistance experiments. (Photo by Dr. Anita Bautista, UP-PGC)

Bautista, together with other scientists, had not only noticed that the moth and its voracious larvae were costing the world upwards of $2 billion annually, but that they had easily developed resistance to insecticides used on cruciferous crops. Her initial work on the moth as an undergraduate student led her to become a Monbukagakusho scholar, earning her PhD in Agricultural Science at Nagoya University. And it was there that she undertook her most popular research project to date.

While many of her peers at the time were looking into classical management systems to try and contain the pest, she wanted to see “at the level of the genes” what mechanisms were behind the moth’s resistance.

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