皖南稻区褐飞虱怀卵雌成虫数量和前期防控对褐飞虱种群动态的影响

通过褐飞虱怀卵雌成虫不同梯度数量下的田间药效试验,研究了安徽省黄山市徽州区单季中稻田二代褐飞虱怀卵雌成虫数量以及前期防控对后期褐飞虱种群动态的影响。试验结果表明:二代怀卵雌成虫数量(x)决定了后期褐飞虱种群大小(y);前期防控(防控:c=1;不防控:c=0)能够明显压低后期褐飞虱种群大小(y);并可建立广义线性回归模型:log(y)=0.943x-3.191c+0.703xc+7.200。根据该模型可以确定两个临界值:(1)x0.4头/百丛时,需要采取"压前控后"策略,即在二、三代低龄若虫高峰期各施药一次,才能有效控制褐飞虱发生危害;(2)x2.4头/百丛时,即使采取"压前控后"的策略,褐飞虱仍然会大发生。2006-2014年大田普查数据亦表明当x2.4头/百丛时,三代褐飞虱极易大发生。本研究明确了褐飞虱前期种群数量对后期发生程度的影响,并可依据前期怀卵雌成虫数量采取不同的防控策略,实现科学防控,减少用药。

Effect of the abundance of pregnant female and chemical control in previous generation on the population dynamics of brown planthopper in Southern Anhui

To investigate the relationship between numbers of the pregnant female in the 2nd generation and all individuals in the 3rd generation of brown planthopper (BPH), Nilaparvata lugens (St?l), field experiments were conducted with different number of pregnant female during June 20th to July 20th in Huizhou, Anhui Province. Results showed that (1) the number of pregnant female in the 2nd generation (x) determined the abundance of BPH in late season (y); (2) chemical control (chemical control: c=1; without chemical control: c=0)applied in the 2nd generation could suppress the population growth of BPH; and (3) these relationship could be modeled by an equation log(y)=0.943x -3.191 c+0.703xc+7.200. Based on this model, two threshold values of population size in the 2nd generation could be calculated, (1) the population in the 2nd generation must be suppressed with chemical control when x>0.4 individuals per 100 hills; and (2) the damage caused by BPH is unavoidable when x>2.4 individuals per 100 hills even if chemical control applied in the 2nd generation. The historical data during 2006-2014 also showed that BPH could be outbreak when the population size of BPH in the 2nd generation greater than 2.4 individuals per 100 hills. These results suggested that different control strategy could be selected to manage BPH according to the number of pregnant female.