Brown spot remains top rice disease concern in Western Visayas

ILOILO CITY — Brown spot remained the leading rice disease in Western Visayas in June, although overall pest and disease pressure across the region stayed low as most farmers had already harvested their crops, according to the Department of Agriculture’s Regional Crop Protection Center (RCPC).

In its June 2026 Rice Monthly Pest Bulletin, the RCPC reported that brown spot posted a regional incidence of 7.18 percent, continuing a three-month upward trend from about 6 percent in April and 6.8 percent in May.

READ: Brown spot remains top rice disease in Western Visayas

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Agriculture specialists attributed the gradual increase to nutrient-deficient fields, crop stress, aging rice plants and humid conditions brought about by intermittent rainfall.

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While the disease has not reached outbreak levels, the RCPC said brown spot remains the primary concern because prolonged infections can reduce grain quality and yield, particularly in stressed crops.

The bulletin was based on surveillance conducted under the Pest and Disease Risk Identification and Management (PRIME) project, which monitors rice pest and disease conditions in selected farming areas across Western Visayas.

The June survey covered 153 monitoring fields, but nearly 90 percent had no standing rice crop after harvest or were still awaiting the next planting season. Only 17 fields remained planted, limiting host plants for insects and diseases and helping keep infestation levels generally low.

Among other rice diseases, leaf blast registered only 0.38 percent, while bacterial leaf blight declined further to 0.24 percent, both remaining well below levels considered economically significant.

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The RCPC said the low incidence of these diseases suggests that current weather conditions and existing crop management practices have helped suppress disease development.

Insect pest pressure likewise remained minimal.

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Stem borer injury was recorded at 1 percent for both deadheart and whitehead damage, while rice bug incidence stood at 0.52 percent.

Although current populations are below economic thresholds, the RCPC advised farmers to continue monitoring stem borers during the vegetative and reproductive growth stages and to keep watch for rice bugs in late-maturing fields because they attack developing grains.

The report also noted that weed cover averaged 5.15 percent across monitored areas. Although lower than in May, the figure remains slightly above the commonly accepted threshold where weeds begin competing significantly with rice for water, nutrients and sunlight.

Meanwhile, rat injury averaged only 0.38 percent, indicating generally low rodent damage. The RCPC nevertheless urged farming communities to sustain coordinated rodent control efforts before populations increase in succeeding cropping seasons.

Province-level monitoring showed varying pest concerns.

In Iloilo, brown spot was the dominant problem at 7.18 percent, followed by weed cover at 5.15 percent, stem borer injury at 1 percent, rice bug at 0.52 percent, and both rat injury and leaf blast at 0.38 percent.

In Aklan, weed cover reached 3.33 percent, with rice bug incidence at 0.67 percent.

Both Capiz and Guimaras recorded weed cover of 5 percent, while Antique had no reported pest records during the monitoring period.

Overall, the DA’s Regional Crop Protection Center described the regional rice pest situation as favorable, with no widespread outbreaks detected during June.

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The agency recommended continued weekly field surveillance, particularly in newly planted rice areas, alongside balanced fertilization, proper water management, integrated pest management practices, timely weed control, and community-based rodent management to keep pest populations below damaging levels in the coming months. /jpv