‘Sting’ operation kills pesky pests

At first glance Roger Gualberto’s cabbage patch looks much like any other: rows of lazy green crowns sitting on low stumps. A closer look however will reveal ant-like creatures prowling the leaves’ surface.

These are the larvae of the diamond back moth (DBM), scourge of cabbages. They feast on leafy crucifers–cabbage, lettuce, pechay, boring holes into your favorite salad greens. The DBM has an appetite for more than leaves; it eats right into the heart of the plant, devouring stems and reproductive cells.

The time tested method for dealing with this plant eater involves spraying with chemical pesticides. It’s effective but it raises the toxicity levels of the plants.

The alternative approach may be the use of a biological ‘control agent’ known as diadegma, which transforms the deadly, voracious moth into a harmless wasp.

Once moth larvae are observed on the plant, the diadegma are unleashed – a ratio of one male for every two females. After mating, the female inject their eggs into thousands of moth larvae. After about a week, the ‘infected’ larvae metamorphize into a diadegma wasp which is actually beneficial to the plant.

This technology was developed by the Department of Agriculture’s (DA) Crop Protection Center based in Mintal, Davao City.

The use of parasitoids-insects such as the diadegma whose larvae are parasites that eventually kill their hosts – is not a new technology having been applied successfully in England, New Zealand, Malaysia and Taiwan.

Still, DA’s plant pathologist, Marilou infante, confirms that it has been difficult to convince local farmers to employ the procedure. Those who agree to try it often continue to use pesticides as well, thus negating the diadegma’s effect.

"Segurista ang farmers natin," Infante explains.

Enter Roger Gualberto of the Maharlika Farmers’ Cooperative in Kapatagan, Digos City, Davao del Sur. Roger seems like any other Davao farmer until he begins discoursing on the merits of his favorite wasps and espousing "integrated pest management’ as a cheaper and safer way to raise vegetables on a commercial scale.

Turns out Gualberto is a former vice president of Union Cement, Inc. who went into farming after retirement. His search for good farm land in Mindanao eventually led Gualberto to upland Kapatagan in Digos, which lies within the Mt. Apo natural park, where he now farms four hectares of land. Roger Chio, Regional DA Director; all of whose persistence helped develop the technology.

Gualberto notes that pesticide-free crops are much in demand in high-end markets such as specialty restaurants, hotels, hospitals and schools. He says the demand from ‘green’ restaurants in Davao alone makes the shift worthwhile.

Gualberto point out that this alternative pest management approach is not meant to replace pesticides totally but rather, to prove that there is a place in the market for biological control agents. This shift is timely since health and environmental concerns are becoming more urgent for food security.

Well and good. Perhaps one day we can all safely bore into our lettuce and cabbage without fear of pesticides. But for now, say a prayer for Roger Gualberto and Maharhalika Farmers’ Cooperative, or better yet, tell your favorite green grocer about the retired boardroom executive now breeding wasps in the boondocks and growing better quality, less chemically-treated food for our tables. – GEM