July 30, 2020
Corn farmers in key corn-growing provinces of Isabela and South Cotabato have successfully controlled the Fall armyworm (FAW) using resistant varieties, including DEKALB corn hybrids.
FAW, which has become a major insect pest in the country, is estimated to bring potential damage between 60% to 80% if corn crops are not managed properly during infestation. In Region 2, up to 80% damage was seen in at least 3,000 hectares in the current season. A fast-reproducing pest that had swiftly spread over Africa, Middle East, and Asia, FAW has brought huge losses to many Filipino corn farmers in previous seasons and appears to continue impacting farms until today.
“It’s only now that I’ve experienced growing corn where worms penetrate deeply into the plants, not just the leaves,” according to Jaime Acedo, a farmer based in Aurora, Isabela. “We are seeing nearly all plants damaged and we don’t expect any yield from this level.”
However, farmer cooperators of Bayer Crop Science (BCS) have witnessed a clear advantage of using FAW-resistant varieties, eliminating the need for manual pest control. According to Acedo, DEKALB VT DoublePro varieties only had 2-3% damage in their field trials, owing to its built-in resistance to multiple lepidopteran insects like Asian corn borer, corn earworm, common cutworm, and the notorious FAW.
Farmers continue to seek help from the government as the FAW is feared to infest even other crops. “FAW is polyphagous, which means it feeds on different kinds of food,” said John Fajardo, BCS Agronomic System Manager for Corn in Southeast Asia and Pakistan. “It has been observed to feed on rice, sugarcane, vegetables, sorghum, and millet.”
In another trial plot in Polomolok, South Cotabato, DEKALB 8719S only had a low pest incidence of 2% based on field observations done 22 days after planting, which was aired over a live Facebook webinar.
“We observed that the leaves and stems of the corn plant did not have any holes,” said Jonel Caberto, BCS Market Development Manager in Mindanao. “Once the FAW seeps into the plant and tries to feed on it, it will stop and eventually perish due to the effectiveness of the VT DoublePro technology.”
All DEKALB varieties with VT DoublePro have 5% refuge in a bag. This government requirement is part of the Insect Resistance Management (IRM) strategy of the industry aimed at minimizing the risk of a resistant population of the target insect pests to grow. With this approach, farmers are assured of the longevity of the technology value to support their livelihood.
Region 2 has suffered serious damage from FAW this season, totaling 3,700 hectares, according to Mindaflor Aquino, Department of Agriculture (DA) Region 2 senior science research specialist. “We only include areas that have been validated, but if you go around corn areas in the region, the actual damage may even be bigger,” said Aquino.
In the Philippines, FAW was first observed in March 2019 in Piat, Cagayan. “It was first identified morphologically by the FAO (Food and Agriculture Organization). From Piat, Cagayan, it was then seen in Gonzaga, Sta. Ana, and other municipalities until it reached the provinces of Isabela, Nueva Vizcaya, and Quirino,” said Aquino.
FAW reproduces quickly with female adults laying 2,000 eggs in a single instance. Its dispersion is fast as it can fly at night over a 100-kilometer distance and up to 500 kilometers with the aid of wind. The insect pest has not spared even some varieties of Bt (Bacillus thuringiensis) corn with single mode of action, which has been known to be resistant only to the Asiatic corn borer.
“Before we thought it’s good that there are very few farmers in Region 2 that still use OPV (open pollinated variety). In Cagayan Valley, we are the highest in the use of Bt corn,” added Aquino. “Unfortunately, this season, we have also seen FAW infestation in Bt corn.” (Melody Mendoza Aguiba)