有机稻田白背飞虱种群动态及其天敌作用

The population dynamics of white back planthopper, Sogatella furcifera (Horváth) (Homoptera:Delphacidae) and effects of the natural enemies in organic rice fields

为组建有机稻田白背飞虱种群生态控制系统,系统调查了实施有机耕作一年后白背飞虱种群动态,并应用生命表技术评价了自然天敌的作用。结果表明,在有机早稻田中白背飞虱发生2个世代,高峰期分别为5月上中旬和6月上中旬,平均百丛虫量分别为435.4和216.4头,干扰作用控制指数IIPC分别为0.3079和0.4044。水稻移栽后天敌回升迅速,移栽15天迁入稻田的蜘蛛为同期常规稻田蜘蛛的2.56倍;捕食性天敌、寄生性天敌数量在移栽42、38天分别为同期常规稻田的1.64与1.40倍。将天敌因子的作用相加,"捕食及其它"和"寄生"因子对白背飞虱种群的控制作用强,其排除作用控制指数(EIPC)值显著高于常规稻田相应作用因子。

To construct the ecological management system of white back planthopper （ WBPH）, Sogatella furcifera （Horváth）, the population dynamic of WBPH was investigated systematically in organic rice fields. The effects of natural enemies were studied using the life table and interference index of population control （IIPC）. The results showed that the WBPH occurred two generations in the paddy fields annually. The two peak periods were from the first to the second decades of May, from the first to the second decades of June, respectively. The average number of WBPH was 435.4 individuals per 100 plants during the first generation, and 216.3 individuals per 100 plants. The increasing rates of WBPH in organic rice fields during the second one were 30.79%, 40.44% higher than those in conventional, respectively. The number of natural enemies increased rapidly after the rice planted. The amount of spider was 2.56 times of that in conventional rice fields after rice planted 15 d. After rice planted 42 d and 38 d, the amount of predators, parasites were 1.64, 1.40 times of those in conventional rice fields, respectively. To add up the effects of the natural enemies＇ factor, predators and others, parasites had a significant role in control WBPH, which EIPC value in organic rice fields were higher than that in conventional rice fields.