Abstract:
Attakkari, a traditional bold-grained rice cultivar favored by consumers in northern Sri Lanka,
continues to be cultivated despite not being a recommended cultivar because of its cooking quality
and tolerance to the flooding. Farmers frequently report yield losses due to pests and diseases;
however, systematic regional assessments are limited. This study, evaluated the major pests and
diseases affecting Attakkari over two growing seasons, Yala 2025 and Maha 2025/2026, across 53
farmer fields. A random sampling method was employed using 1 m × 1 m quadrats in the paddy
fields. The incidence and severity of each pest and disease were assessed using the standard
evaluation system for rice developed by IRRI, along with environmental parameters, including
temperature, rainfall, and relative humidity (RH). During Yala, bacterial blight was severe in Mannar,
with 80% incidence and a severity score of 9.0, following high temperatures (>32 °C) and rainfall of
42.5–56.7 mm recorded 2 weeks earlier. Leaf folder incidence reached a severity score of 9.0 in
Mannar. Yellow stem borer showed moderate incidence with low severity, while brown spot was
widespread at early growth stages. In Maha, fungal diseases were predominated. Brown spot affected
all surveyed fields in Jaffna and Mullaitivu, with peak severity (9.0) at Oddusuddan following
extreme rainfall and sustained RH. Leaf and panicle blast occurred only in Jaffna, with incidence up
to 50% and severity up to 7.0 under cooler temperatures ( 32 °C (r = 0.68, α = 0.05), a negative
association between blast and temperature (r = -0.54), and a strong correlation between brown spot
and 30- day cumulative rainfall (r = 0.82). Sites with ≥ 10 consecutive days of RH > 85% exhibited
3.2-fold greater brown spot severity. These findings indicate the importance of continued multi-season
evaluation and integrated pest and disease management strategies for sustainable cultivation of
Attakkari rice.
