The Joint-toxicity Measurement And Bioactivity Of The Extracts Collected By Methyl Alcohol From Sophora Alopecuroides With Emamectin Benzoate On Meloidogyne Incognita

Plant root-knot nematodes are an economically important soil-borne pathogens, which have hitherto been controlled mainly by nematicides, but with an increase awareness of the harmful effects of chemical ones and the changing attitude towards environmental pollution, several effective chemical nematicides are forbade among farmers for protecting crops. Binary mixture of insecticides may keep people’s eyes on insecticides, decrease the application rate of insecticides and postpone the development of insect resistance. This study aimed to provide scientific basis of the mixture of Emamectin benzoate and methanol extract from Sophora alopecuroid.es L. in the Meloidogyne control based on the results of laboratory and pot experiments.The results could be summarized as follows:1. In order to distinguish the species of root-knot nematodes occurring in greenhouse in Taian of Shandong Province, and provide effective prevention, root-knot nematodes samples were collected from Taian of Shandong Province. Based on morphology and mtDNA, M. incognita, and M. arenaria were identified. Results showed M. incognita was the dominant specie in greenhouse. M. incognita should be the main control object. At the same time, the mixed infection should be noticed, too.2. In order to find new effective and low toxic Nematicide for the control of M. incognita, the bioactivity of Emamectin benzoate and methanol extract from Sophora alopecuroides L. to M. incognita was investigated by toxicity test and pot experim ent. The results showed that the methanol extract from S. alopecuroides could effectively control M. incognita. Treating M. incognita with3000mg/L methanol extract for48h could lead to94.37%of corrected mortality, its LC50being510.38mg/L.The results showed that the toxicity of Emamectin benzoate to second juveniles of M. incognita was higher in the lab. Their LC50to second juveniles for24h、48h、72h were5.972、6.477、5.861mg/L, but the toxicity of Emamectin benzoate for48was higher than that for24h and72h, which showed that nematicidal activities of Emamectin benzoate was reversible, but some nematodes clobbered may resurge for a certain time.3. Sun’s method was used to determine the co-toxicity coefficient (CTC) of binary mixture of Emamectin benzoate and methanol extract from Sophora alopecuroides L. to the M. incognita. The results showed that the CTC of this compound at different ratios were all over100,which showed the strongest toxicity to J2.The CTC of KJIII was131.75, and the LC50value was18.944mg/L, which showed visible synergy. The results of KJ III toxicity measurement to Jj and hatching showed that The revised mortality J2of different treatments were above80%after48h, the effect of inhibition was better than the J2.4. Pot control efficacy of Emamectin benzoate on M. incognita of tomato as well as its safety to tomato was investigated. Pot experiment showed KJⅢ was very efficacious on controlling this disease, and its relative control efficacies were94.94%when100mg/L of KJⅢ were used. Reproduction index was only0.1, Emamectin benzoate also could significantly inhibit the producti on of M. incognita and egg sacs. At the same time, Emamectin benzoate was also very safe to the tomato growth. The study indicated that methanol extract from Sophora alopecuroides L. mixed with Emamectin benzoate could control M. incognita of tomato.