Forecasting the Brown Planthopper, Nilaparvata lugens (Stål) Outbreak in Chai Nat Province Using Light Trap

Abstract

The brown planthopper (BPH), Nilaparvata lugens (Stål) has been a major pest in irrigated rice growing areas of central and lower northern region since 1975. The monitoring of population density is very important for forecasting the BPH outbreak. Light trap, an effective tool for monitoring the outbreaks of BPH was conducted in hot spot areas. A light trap was set in Chai Nat Rice Research Center while surveying in farmers' fields in hot spot areas of BPH outbreak in Chai Nat province were investigated during October 2005 to September 2007. The number of BPH caught from light trap was counted everyday throughout the year. The results showed that light trap could collect big number of BPH. The peak of BPH in light trap was more than 170,000 hoppers/trap/month which related to the BPH outbreak in farmers' fields. This peak could indicate the BPH outbreak in hot spot areas in Amphoe Mueang, Hunka, Wat Sing and Manorom. Factors effecting severe outbreak were rice varieties and number of immigrant natural enemy (mirid bug). The resistant variety showed BPH outbreak less than the susceptible one. The number of 40,000-70,000 hoppers/trap/month indicated the BPH outbreak, warning the farmers to take survey the insects in their fields. The peak of BPH in light trap trended to relate with the BPH abundance in the fields at 15-20 days after seeding.