Effects of meteorological factors and global warming on rice insect pests in Korea

We examined the occurrence patterns of insect pests in paddy fields using a self-organizing map (SOM) and the influence of meteorological factors on these patterns. Data for nine insect pests and three meteorological factors were collected on the Korean nationwide scale from 1992 to 2008. The SOM analysis was based on annual mean densities of each pest species in eight regions. We classified the samples into five clusters (I-V) to display the spatial and temporal changes in the insect pests' occurrences. Clusters I and II included samples collected before 2000; clusters III and IV included samples collected after 2000. The density of Scotinophara lurida was in the lowest range in clusters I and II, and Lissorhoptrus oryzophilus exhibited higher densities in clusters Ill and IV. Seasonal temperature, humidity, and precipitation were significantly different among clusters, indicating that these factors play a key role in population dynamics and the occurrence of insect pests. The occurrence area of the insect pests was expected to increase with elevated air temperature influenced by global warming based on the IPCC (Intergovernmental Panel on Climate Change) A1B scenario. This study suggests that gathering data on temporal and spatial variations in pest populations and changes in occurrence rate under the effects of global warming can provide insight into the factors governing the population-environment relationships, as well as the information needed for future pest management. (C) Korean Society of Applied Entomology, Taiwan Entomological Society and Malaysian Plant Protection Society, 2012. Published by Elsevier B.V. All tights reserved.