By Benjamin A. Gutierrez
Municipal Agriculturist
Cuartero, Capiz
A potent threat to the performance of rice crops is the presence of yield-reducing insect pests like the brown plant hoppers (BPH), Nilaparvata lugens (Stal) (Hemiptera: Delphacidae). These insects do not only cause the wilting and drying of rice plants (as hopper burns); they also transmit the grassy stunt and ragged stunt virus diseases.
Latest field observations in Capiz showed that a significant portion of rice areas suffered from hopper burns in patches and in irregular patterns of infestation. LGU reports on the BPH damage in September 2010 revealed that the area damage ranged from 10 to 50%, while the degree of hopper burns in each of the rice farms affected ranges from 10% to 100%. Said figures on BPH in the area only validate the recorded population of 4 to 12 hoppers per tiller and 20 to 180 BPH adults per 10 sweeps, which is higher than the usual 1 BPH adult per tiller.
Besides adopting asynchronous rice plantings in their affected areas, rice farmers can spray chemicals to counter these insect pests. Previous and current programs of the national government on pest control and management encourage such practices.
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| SPOT THE DIFFERENCE. Left photo shows a rice farm in Capiz infested by BPH in 2010. The lower green portion was later infested by the disease in concentric pattern. Right photo shows rice field in the adjoining area not infested by the BPH. |
How to Control and Manage Brown Plant Hoppers
What follows are practical solutions you can do to counter threats posed by BPH or waya-waya.
Plant rice varieties which are resistant to BPH—like PSB Rc 10 (Pagsanjan), PSB Rc 32 (Jaro) and PSB Rc 34 (Burdagol). This is the most practical and effective means to control rice disease. But not all modern or high-yielding varieties possess resistance to all pests. Pests to which the said varieties are susceptible may also grow unchecked.
Follow contiguous or clustering with similar planting schedule. This scheme will break the pest’s life cycle that will eventually minimize insect pest population buildup to damaging level.
Regulate the planting density based on the recommended seeding rate or plant population per unit area.This will help reduce the BPH populations by providing a lesser favorable environment during infestation.
Apply the right kind and amount of nitrogen fertilizer. Excessive chemical N fertilizer applications will enhance the development of many insect pest species while the application of inadequate amount of N and other nutrients needed by the rice plants will make them more susceptible to damage.
Do not destroy the bunds along the rice and non-rice areas. These areas serve as sources of foods (pollen and nectars from the flowers of plants) mostly for the beneficial organisms. When insecticide is applied in the rice area, the bunds also serve as the hiding places for beneficial organisms where they could populate.
Do not spray chemicals within 40 days after seeding or 30 days after transplanting. When spraying is done within this period, a big number of beneficial organisms will die, so pests multiply exponentially because said organisms are absent. Hence, insect pest outbreak occurs.
By reducing or properly choosing insecticides, allow for the preservation and augmentation of the population of beneficial organisms. These organisms include the egg masses and adults of mirid bugs, dragonflies and damselflies, spiders and other hymenopteran insects.
Reduce the frequency of chemical application to slow down the development of insect resistance to insecticides. BPH endemic in the Philippines are slow-developing resistant pests, but in China, Thailand and Indonesia they develop 1,000 times because of insecticides resistance caused by the heavy use of chemicals.
When the rice plants are sprayed with insecticides, BPH have higher fecundity or ability to multiply.
If the BPH population is in epidemic or damaging level and the rice plants are in the vulnerable (tillering) stage, spray selective insecticides and integrate with water management. This will minimize infestation and damage.
Visit and monitor twice a week your own rice fields and those of others nearest your area. Because BPH are present year-round and their migration from other areas is highly possible, regular field observation may also help identify the potential pest problems for preventive and corrective management.
References
Catindig J., S. Villareal, and R. Saltin. 2010. “Planthopper Outbreaks in Iloilo, Philippines.” A report posted by the International Rice Research Institute, Los Baños, Philippines and Department of Agriculture Regional Office, Iloilo City.
Gutierrez, BA and GL Gregorio. 2001. “Population dynamics of insect pest and their predators among lowland rice varieties applied with varying rates of nitrogen fertilizer.” PSPC Research Journal 8:1: 1–18.
Heong, K. L. “Tips in controlling and managing rice planthoppers.” Ecological Entomologist. Los Baños: International Rice Research Institute.
Ministry of Agriculture and Food. 1986. Integrated Pest Management: Rice. Philippine-German Crop Protection Programme: Pocket Reference Manual. Malate, Manila: Bureau of Plant Industry.
Philippine Rice Research Institute. 2004. Integrated Pest Management Question and Answer Series No. 3. Muñoz, Nueva Ecija.
Way, MJ and KL Heong. 1994. “The role of biodiversity in the dynamics and management of insect pests of tropical rice a review.” Bulletin of Entomological Research No. 84. 567–587.
Webster, Robert K. and Pamela S. Gunnell. 1992. Compendium of Rice Diseases. St. Paul, Minnesota: The American Phytopathological Society.
