摘要
[Objectives] The aim was to study the contact activity of combination use of garlic,onion and stone calamus extracts on Helicoverpa armigera and their co-toxicity coefficient( CTC) and mixture ratio. [Methods] Leaf dipping method was used to study the contact activity of the three kinds of plant extracts against H. armigera. Based on this,the co-toxicity coefficient of the compound of the three kinds of extracts was determined. Orthogonal test was used to explore the optimal mixture ratio of the three kinds of extract for combination use. [Results]The extracts of garlic,onion and stone calamus had good inhibition and contract activity on H. armigera larvae. The LC50 values of the three kinds of plant extracts against H. armigera were 175. 0,217. 0 and 79. 2 mg/L,respectively. When the mixture ratios of stone calamus to garlic,and stone calamus to onion were both 2:1,the extract showed a synergistic effect( CTC > 120); when the mixture ratios of stone calamus to garlic,and stone calamus to onion were 1:1 and 1:2,respectively,the extracts showed an additive effect( 80 < CTC < 120); and then garlic extract and onion extract were mixed according to the ratio of 1:1,the additive effect was slight( CTC < 90). Among the three kinds of extracts,the extract of stone calamus showed the strongest contact activity,followed by that of garlic. The results of co-toxicity coefficient determination and orthogonal test showed that the contact activity of combination use of the three kinds of extracts was stronger than that of the single extract overall. When the extracts of garlic,onion and stone calamus were mixed according to the ratio of 2:3:1( mass concentration ratio),the contact activity of the compound against H. armigera reached 95. 3%. [Conclusions]The study results provide a scientific basis and theoretical reference for the development of new plant-derived pesticides based on the pharmacodynamics of garlic,onion and stone calamus.
[Objectives] The aim was to study the contact activity of combination use of garlic,onion and stone calamus extracts on Helicoverpa armigera and their co-toxicity coefficient（ CTC） and mixture ratio. [Methods] Leaf dipping method was used to study the contact activity of the three kinds of plant extracts against H. armigera. Based on this,the co-toxicity coefficient of the compound of the three kinds of extracts was determined. Orthogonal test was used to explore the optimal mixture ratio of the three kinds of extract for combination use. [Results]The extracts of garlic,onion and stone calamus had good inhibition and contract activity on H. armigera larvae. The LC50 values of the three kinds of plant extracts against H. armigera were 175. 0,217. 0 and 79. 2 mg/L,respectively. When the mixture ratios of stone calamus to garlic,and stone calamus to onion were both 2：1,the extract showed a synergistic effect（ CTC 〉 120）; when the mixture ratios of stone calamus to garlic,and stone calamus to onion were 1：1 and 1：2,respectively,the extracts showed an additive effect（ 80 〈 CTC 〈 120）; and then garlic extract and onion extract were mixed according to the ratio of 1：1,the additive effect was slight（ CTC 〈 90）. Among the three kinds of extracts,the extract of stone calamus showed the strongest contact activity,followed by that of garlic. The results of co-toxicity coefficient determination and orthogonal test showed that the contact activity of combination use of the three kinds of extracts was stronger than that of the single extract overall. When the extracts of garlic,onion and stone calamus were mixed according to the ratio of 2：3：1（ mass concentration ratio）,the contact activity of the compound against H. armigera reached 95. 3%. [Conclusions]The study results provide a scientific basis and theoretical reference for the development of new plant-derived pesticides based on the pharmacodynamics of garlic,onion and stone calamus.
