Ways to Prevent Deadhearts, Whiteheads
Infestation of stemborers can result in a yield loss of as high as 50 percent.
According to Rolando San Gabriel, PhilRice training specialist, stemborer adult population peaks from April to May and October to November.
Stemborer damage during vegetative stage is manifested by yellow, dead, young leaves or dead tillers called deadhearts (which can be easily pulled from the base), while damage during reproductive stage is manifested by whiteheads or emergence of whitish and unfilled panicles. Severe stemborer damage causes a decrease in the number of reproductive tillers. To prevent deadhearts and whiteheads, proper management practices must be integrated.
“If there are more than five egg masses in seedbeds, and one or more egg masses spotted during its mid to maximum tillering per square meter, measures must be observed,” San Gabriel said.
Preserving the natural enemies of stemborer such as crickets; birds; spiders parasitic wasps; pathogenic viruses; and fungi, is one way of managing this pest. Crickets serve as – egg predators while birds and spiders as adult predators. Parasitic wasps attack the eggs and larvae while pathogenic viruses and fungi attack the larvae. San Gabriel advises farmers to keep insecticide usage at a minimum level to protect natural enemies.
Synchronous planting after a fallow period of at least one month in the community is an equally effective strategy to manage stemborers. It avoids overlapping incidences of insect populations. On the other hand, fallow period for at least one month breaks insect pest cycle and destroys hosts.
The combination of plowing and flooding is the most effective way to destroy the larvae or pupae as most stemborers thrive in stubbles between crops. Harvesting at ground level also removes these larvae, San Gabriel added.
Popularity: 2%
Popularity: 2%
