大豆蚜阶段特异性经济阈值的制定

Stage-specific economic thresholds for Aphis glycines(Matsumura)(Hemiptera:Aphididae)

为制定大豆蚜Aphis glycines阶段特异性经济阈值,于2015-2018年连续4年开展田间试验,通过定点、定株调查和产量测定,运用回归分析法研究大豆4个特定生长阶段下不同密度大豆蚜侵染对其产量损失的影响。结果表明,在大豆4叶期-初花期阶段,大豆蚜侵染的累计蚜日及其种群增长率均最大,分别达到40 900头·日和0.184,大豆产量损失率也最高,达到了60.96%。大豆蚜的侵染密度与产量损失率在大豆出苗期-4叶期和4叶期-初花期阶段使用线性模型拟合的优度最高,在初花期-初荚期和初荚期-鼓粒期阶段使用对数曲线模型拟合的优度最高,并构建了各阶段的回归方程。基于反映市场价值和潜在产量变化的动态经济允许损害水平,得到大豆出苗期-4叶期、4叶期-初花期、初花期-初荚期和初荚期-鼓粒期阶段的平均蚜量阈值分别为79、227、323和460头/株;依据线性相关性转换得到更利于实际应用的阈值指标--有蚜株率和卷叶株率,如果提前3 d进行防治,则出苗期-4叶期阶段的有蚜株率阈值为17.88%,4叶期-初花期、初花期-初荚期和初荚期-鼓粒期阶段的卷叶株率阈值分别为4.78%、7.88%和12.59%。表明大豆蚜阶梯式的阶段特异性经济阈值随大豆生育期的推进而放宽;且提前3 d的准备时间便于种植者进行早期决策,从而有针对性地选择防治大豆蚜的作物生育期。

In order to establish the stage-specific economic thresholds for Aphis glycines, field experments were carried out from 2015 to 2018. Through fixed-point and fixed-plant investigations, the relationship between the A. glycines population density and the soybean yield losses was studied in four specific soybean growth stages using regression analysis. The results showed that both the cumulative aphid-days and the population growth rate of A. glycines reached the maximum of 40 900 aphid-days and 0.184, respectively, when the initial infestation occurred in the 4-leaf to the initial flowering stage,with a highest soybean yield loss rate of 60.96%. The goodness of fit using the linear model was the highest in the emergence to the 4-leaf stage and the 4-leaf to the initial flowering stage between the A.glycines population density and the soybean yield loss rate;using the logarithmic curve model, the highest goodness of fit was observed in the initial flowering to the beginning pod stage and the beginning pod to the beginning seed stage. The regression equations were constructed for each stage. Based on the dynamic economic injury levels that reflected the changes in both the market price and the potential yield, the average aphid quantity thresholds in the emergence to the 4-leaf, the 4-leaf to the initial flowering stage, the initial flowering to the beginning pod and the beginning pod to the beginning seed stage were 79, 227, 323 and 460 aphids/plant, respectively. According to the linear regression, the colonized plant rate and the rolled leaf plant rate were obtained, which are more suitable for practical use. The calculations showed that the colonized plant rate threshold with a 3 d-lead time in the emergence to the4-leaf stage was 17.88%, and the rolled leaf plant rate threshold with a 3 d-lead time in the 4-leaf to the initial flowering stage, the initial flowering to the beginning pod and the beginning pod to the beginning seed stage were 4.78%, 7.88% and 12.59%, respectively. The results indicated that the scalar stage-specific economic thresholds of A. glycines were loosened with the improvement of the soybean growth period. Moreover, a 3-d preparation time before the aphid quantity reached the economic thresholds benefits the growers by making early decision for controlling A. glycines by selecting specific soybean developmental stages.