Preliminary Study Of Control Techniques On Different Formulaitons Of Emamectin Benzoate To Two Plant Pathogen Nematodes

M.incognita and Cereal Cyst Nematode are two important nematodes in the vegetablesand wheat, seriously affecting agricultural production and quality. In order to evaluate thepotential prevention and control ability of emamectin benzoate on M.incognita and cereal cystnematode, and to guide its scientific use, the indoor bioassay, pot experiment and fieldefficacy trials was experimented. This paper cleared the toxicity of emamectin benzoate onthe two nematodes, and the affection of the formulation, the dose and application time andother factors on the prevention effects of two nematodes. The main results are as follows:1An in vitro assay was used to examine the antinematodal activity of10availablecompounds with known modes of action. Among compounds testes, the GABA receptoragonists had better anti-nematodal activity than other compounds. The Avermectins andEmamectin benzoate strongly inhibited the nematodes. Emamectin benzoate proved to be themost active compound. It is concluded that Emamectin benzoate is a strong candidate for ananti-nematodal to the two plant-parasitic nematodes, and the lowest effective dose to CCN is0.5¹mg/kg, and the root nematode is0.1⁰.5mg/kg.2In order to compare the degradation dynamics in the soil of emamectin benzoate, thispaper studies the HPLC-UV of emamectin benzoate. In the stuy of HPLC-UV, an analyticalmethod was experimented for testing three kind of preparations of emamectin benzoate andcompared the insecticide degradation trends in soils. The results showed that the liquidchromatography（HPLC）was established for the exacting method （the CS and GR needed atleast2h to ultrasonic and30min to shake which is longer than EC and the standard） to thetest pestiside and the degradation of three emamectin benzoate preparations in soil could bedescribed with equation of C_t=C₀e^-kt. The degadate half-life of emamectin benzoate turned indifferent formulation was estimated to be71.46¹23.78d for granules,45.90⁵9.24d formicrocapsule suspension or28.88³7.67d for emulsifiable concentrate in soil, respectively.3In the stuy of HPLC-FD, the aim of this study is to investigate some experimentalparameters that influence derivatization efficiency, such as the time, the temperature, the light,the concentration of derivatization reagent and the stability of the derivatived products andbuild a sensitive HPLC-FD method for determinating emamectin benzoate in soils. Thesample used to study the effects of the factor was derivatised by TFAA-NMIM-CAN system.After being extracted by Methanol, the emamectin benzoate in soils were analyzed onHPLC-FD. Results showed that Derivatization efficiency will reached the highest under20℃, NMIM-CAN（1+9） and TFAA-CAN（1+9） without light. Then the fortified recovery and variation coefficient of added compounds in samples were91.74%¹02.68%and2.55%⁷.55%, respectively, the limited level of detection was0.001mg kg^-1. The factorshave a significant impact on the derivatization. The HPLC-FD method is accurate and reliable,all validated parameters of this method are sufficient for analysis of pesticide residue.4In order to establish the control technology of the cereal cyst nematode withemamectin benzoate, a study was experimented on different formulations, application ondifferent periods and ways of emamectin benzoate on controlling the cereal cyst nematode tocompare the effects, the impact of pesticides on the infection dynamics and the degradationdynamics in soil. The results showed that Cereal Cyst Nematode infection peak is after thewinter, the range of the different formulations’ half-life is27.40⁶7.30d, and themicro-capsules and granules has a longer persistence. It is concluded that the best pesticideapplication is spaying with the irrigation with the water after the winter, and with the amountof active ingredient100g/hm², the control effect of micro-capsules can achieve to80%.5To establish control techniques of a single plant irrigation to control root-knotnematode, the test is to study on the distribution of emamectin benzoate in soil with differentirrigation volume, and the effective and the quality of tomato of the different treatment. Theresults show that under the loose soil conditions, with increasing irrigation volume thedistribution of emamectin benzoate in soils will be more uniform, the local maximumconcentration decreased and the quality of tomato improved. It is concluded that the bestcontrol techniques is under the irrigation of800mL or1600mL, and the amount of activeingredient is10mg per plant.