Analysis of factors affecting population growth of the  white-backed planthopper (Sogatella furcifera) in  early rice crop areas of Yunnan Province
											  
												Author of the article:LI Xiang-Yong1**  CHEN Ai-Dong1***  Tian Wei-Kui2   Shi Xiao-Yun2  YIN Yan-Qiong1   ZHAO Xue-Qing1
												Author's Workplace:1. Institute of Agricultural Resources and Environment, Yunnan Academy of Agricultural Sciences, Kunming 650205, China;  2. Plant Protection and Quarantine Station of Menghai County, Yunnan Province, Menghai 666200, China
												
												Key Words:SogateIla furcifera, orthogonal experiment, population proliferation
												
												Abstract:
	 [Objectives]  To determine the population growth rate of the white-backed planthopper (SogateIla furcifera (Horváth) on different rice varieties, at different stages of the rice growing season, and different initial plant-hopper population densities. [Methods]  We used an orthogonal experimental design to analyze the impact of initial planthopper density, rice variety, and stage of the growing season, on the population growth rate of S. furcifera. [Results]  Population growth rates were significantly affected by both rice developmental period (P<0.01) and initial planthopper density (P<0.05). Population growth rates during the transplanting period, jointing stage, booting stage, and heading stage, were 10.0, 8.8, 2.6 and 1.3, respectively; the population growth rate during the transplanting period was significantly higher than that recorded during all other growing stages (P<0.01). Growth rates at 4 initial densities (5 pairs/clump, 10 pairs/clump, 20 pairs/clump, 40 pairs/clump) were 9.2, 6.1, 4.3 and 3.1, respectively; the growth rate at 5 pairs/clump was significantly different to that at 40 pairs/clump (P<0.01), and to that at 20 pairs/clump (P<0.05). Population growth rates on the rice varieties Dianlong 201, Liangyou 2161, Neiwuyou 306 and Liangyouduoxi 1 were 7.8, 5.9, 4.3 and 4.8, respectively, which were not significantly different (P>0.05). [Conclusion]  There was no significant difference in the population growth rate of the white-backed planthopper on different rice varieties in the early rice season in Menhai County. Lower initial density of S. furcifera can result in a faster population growth from the transplanting to the jointing stage.