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褐稻虱在苏北中粳稻区通常一年发生4代,主害代为第七(4)代。常年七(4)代第一若虫高峰在9月上旬末左右:第二若虫高峰在9月20日左右。在中粳稻区大发生的频率高,给水稻生产造成严重威胁。因此,对褐稻虱发生期、发生量预报的成败直接影响到防治效果和水稻产量。为此,我们在初步掌握发生规律的基础上,对我县中粳稻褐稻虱发生期及发生程度中、长期的预报进行了研究,现将结果初报如下;一、发生期预报据本县12年来的观察资料分析:五(2)代成虫高峰与六(3)代若虫高峰(二、三龄若虫占50%以上)期距99%可靠度的置信限为 Ln=15.5±0.62(天);六(3)代成虫高
Brown planthopper in northern Jiangsu Province usually occur in four generations a year, the main agent for the seventh generation (4) generation. Perennial seven (4) on behalf of the first nymph peak in late September or so: the second nymph peak around September 20. The high frequency of occurrence in the mid-japonica rice area poses a serious threat to the rice production. Therefore, the occurrence of brown planthopper, the occurrence of the amount of forecast success or failure of a direct impact on control and rice yield. To this end, we preliminary grasp the law of occurrence on the basis of my county in the occurrence and occurrence of mid-and long-term brown rice louse in the medium and long-term forecasts were conducted, the results are as follows: First, the forecast period According to the county 12 years of observation data analysis: five (2) generations of adult peak and six (3) generation nymphs peak (second and third instar nymphs accounted for more than 50%), the reliability of 99% confidence interval for the Ln = 15.5 ± 0.62 (days ); Six (3) generations of adult height