Experts at the Philippine Rice Research Institute (PhilRice) warned farmers to reduce insecticide use in controlling rice black bugs, which reportedly attacked some rice fields in Central Luzon.
Entomologists Gertrudo Arida and Dr. Hoai Xuan Truong stated in the PhilRice-published bulletin titled, Management of the Rice black bug, that insecticides should be used to a minimum so as not to kill the natural enemies of rice black bugs.
Enemies of the tiny pests include wasps; ground and coccinellid beetle; wolf, lynx, and long-jawed spider; red ant; and damsel bug.
When not properly controlled, 10 adult rice black bugs per hill can cause losses of up to 35 percent. However, Arida and Truong said that attacks of rice black bugs, locally known as itim na atangya, can be prevented at the start of the planting season.
They advised farmers to plant rice varieties with same maturity within a month of the barangay`s regular planting time as this breaks the pests` life cycle.
During outbreaks, researchers at PhilRice`s Crop Protection Division recommended the use of light traps because the bugs are strongly attracted to high intensity light.
“Light trapping of insects should start five days before and after the full moon. Use 2000-3000 watts or super light during outbreaks and set them up every night to obtain the most number of bugs. Effective light trapping is from 8 to 12 pm,” the experts said.
Flooding, herding of ducks in the field, and sanitation also prevent pest infestation.
“We advise farmers to flood the field to submerge egg masses. Eggs that are submerged for more than 24 hours will no longer hatch. Ducks also feed on the bugs. However, herd the duck in the field a month after transplanting or when the plants are established. Farmers must also clean their field by removing the weeds as these serve as alternate hosts of the rice black bugs,” they explained.
The first reported incidence of rice black bug attack was in Bonobono, Bataraza, in Southern Palawan in 1979. A major outbreak occurred in 1982, spreading towards Central up to Northern Palawan. However, massive and intensive insecticide applications failed to control the damages that covered 4,500 ha of rice fields.