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粘虫幼虫为害量大,虫笼内平均每头幼虫可为害大麦12.94±1.59株,叶16.94±3.26片,其中剑叶10.50±1.43片,由于天敌控制作用,田间粘虫存活率与虫口密度显著呈幂函数关系,实际为害仅为虫笼内的一半左右。 调查表明,株受害率与3龄高峰期虫口密度及麦株密度显著相关;受害株损失率与为害时期显著呈指数函数关联;田块损失率与株受害率亦显著呈指数函数关系,组合各关系式,建立了以虫口密度预测受害株率和损失率的模式 组建立了一个经济阈值模型 据此,提出下列经济阈值 早发年:每亩6000头; 常发年:每亩10000头; 迟发年:每亩15000头。
Larvae of the armyworm larvae had a large amount of damage. The average larvae in the cages were 12.94 ± 1.59 barley per plant, 16.94 ± 3.26 leaves and 10.50 ± 1.43 leaves, respectively. Owing to the control of natural enemies, the survival rate and population density A power function relationship, the actual damage is only about half of cage inside. The investigation showed that the strain damage rate was significantly related to the population density and density at the 3rd instar peak. The damage rate of the damaged strain was significantly related to the damage time. The loss rate and the damage rate of the strain also showed an exponential function. The establishment of an economic threshold model based on the model group of insect population density and loss rate predicted by insect population density. Based on the above, the following economic thresholds were proposed for early onset: 6000 heads per acre; usual year: 10,000 heads per acre; late Year: 15000 heads per acre