Author(s)
Kothai Kaveevendan, Christy Jeyaseelan Emmanuel, Devika Malkanthi De Costa
Abstract
Onion is a vital crop for the Sri Lankan economy, yet its productivity is severely constrained by anthracnose–twister disease (ATD) caused by Colletotrichum and Fusarium species. This study assessed farmers’ awareness, perceptions, and management practices related to the disease across seven major onion-growing districts: Jaffna, Kilinochchi, Mullaitivu, Trincomalee, Puttalam, Matale, and Anuradhapura. A descriptive cross-sectional survey was conducted among 350 farmers using a structured questionnaire that covered demographic characteristics, agronomic practices, pest and disease management, and farmer knowledge on ATD identification and varietal resistance. Data were analyzed using descriptive statistics and binary logistic regression. Results revealed that most farmers were male, middle-aged, and primarily cultivated shallots, while bulb onion cultivation dominated in Matale and Anuradhapura. ATD was the most prevalent constraint, particularly during the Maha season, leading to yield losses exceeding 50 % in several districts. Logistic regression analysis revealed that seasonal conditions, onion variety, land preparation, plant spacing, watering frequency, and irrigation method significantly influenced ATD incidence. Frequent watering and surface irrigation substantially increased disease risk, whereas wider spacing (10 cm × 10 cm), improved land preparation, and reduced irrigation frequency significantly lowered infection probability. Awareness of resistant varieties was limited across most districts, and chemical control remained the dominant management strategy. Overall, the findings highlight the need for integrated disease management approaches that combine improved agronomy, climate-adapted irrigation, farmer education, and the development and adaptation of resistant cultivars to mitigate ATD impacts and sustain onion productivity in Sri Lanka.