Study on outbreaks of brown planthopper (Nilaparvata lugens) in rice cultivation; A farmer survey

Abstract

Brown Planthopper (BPH), Nilaparvata lugens causes adverse effect to rice production in Sri Lanka. Over the last three decades, the area affected and damaged by BPH fluctuated respectively from 0.01% to 5% and from 0.01% to 0.1% of the annual cultivated extent. Therefore, it is essential to take precautions to keep the pest incidence under threshold levels and prevent spreading through sustainable management of BPH dispersion in paddy production systems in Sri Lanka. This study was conducted to understand the farmers’ pest management practices and evaluates its effect on the BPH damage management. The selection of the study areas was based on the irrigation regime. Therefore, Kurunegala, Rathnapura and Mahaweli system B, C have been selected representing the rain-fed, minor irrigation and major irrigation system categories respectively. A pre-tested questionnaire survey was conducted in Maha season of 2018/19 using interview method to collect data140 farmers from four selected areas by using simple random sampling methods. This survey revealed that, BPH was the dominant pest as in these three districts and even the majority of experienced farmers in these areas, followed improper pest management practices such as improper land preparation practices (10%- Kurunegala 12% Ratnapura, 20% - Mahaweli B, 25% Mahaweli C), seed rate utilization (>40kg/Ac 23% Kurunegala, 10% Ratanapura, 38% Mahaweli B, 40% Mahaweli C), late identification (22% Kurunegala,18% Ratnapura, 32% Mahaweli B, 40% Mahaweli C and chemical application. Therefore, in order to minimize the risk of BPH, conducting farmer awareness and demonstration programs, selecting proper insecticides, proper spray volume and applying them at a correct time and following a proper method of application can be made into practice.