Effects Of Insecticides On Hatching?Penetration And Behavior Of Heterodera Elachista

Chemical control is the main method of rice disease and pest control. The long-term use of insecticides on the rice not only bring the pesticide residue, environmental pollution problems, it can also change the biology and ecology behavior of terrestrial organisms, aquatic organisms and soil organisms in farmland ecological environment,thus affecting the whole agricultural ecosystem. In recent years, The trend of insecticides on rice in china is low toxicity, high efficiency and high selectivity, some of the highly toxic pesticides are prohibited to use. Heterodera elachista is one of the rice parasitic nematodes found in the South Hills area in recent years. In order to know the effects and control function of insecticides on Heterodera elachista, In this study, The impact on hatching, penetration, diffusion and feeding behavior of Heterodera elachista, as well as the protective effect of rice seedlings with six common insecticides on rice have been studied, including abamectin, profenophos, chlorpyrifos, bisultap, ethoprophos and triazophos. The study provided scientific guidance to the rational use of insecticides on rice and the control of Heterodera elachista. The main results are as follows:1. Six pesticides have been used in this study, including chlorpyrifos, triazophos, ethoprophos, profenophos, abamectin and bisultap. The effect on Heterodera elachista hatching has been determined with in different concentration of six pesticides and different time processing in indoor conditions. The results showed, that profenofos and chlorpyrifos. abamectin had high inhibitory activity to hatching of Heterodera elachista:The inhibitory effect of long-term treatment on the hatching of 2 instar larvae was the best.Compared with the cysts that had already been pre-incubated for 7 days, just isolated cysts has low sensitivity to drug; Triazophos and ethoprophos can stimulated the incubation of cyst nematode in the lower concentration range.2. As PluronicF-127 gel to a culture medium, by the way of mixing the culture matrix which contained a series of concentrations of drug with the rice seedling.the study measured the effects of insecticides for the test on Heterodera elachista infestation. After 15 days of treatment, the results showed that in Pluronic(?)F-127 gel matrix culture the insecticides for test inhibited the infection of Heterodera elachista and the inhibitory activity size was: abamectin>profenophos> chlorpyrifos> bisultap> triazophos> ethoprophos, and ethoprophos at the lowest concentration that can stimulate the nematode infestation.3. By the method of insecticides incubated with a fluorescent dye Cy3,this study measured effects of three pesticides on Heterodera elachista feeding, the results showed that: when profenophos and carbofuran concentrations were 2.5 ?g/mL and 60 ?g/mL, Heterodera Elachista feeding stimulates more than 90%, when profenophos and carbofuran concentrations were 300 ?g/mL and 500 ?g/mL, suppressed all nematode feeding; Abamectin can't stimulate the nematode feeding, with 100 ?g/mL of profenophos liquid stimulate nematode feeding,then use abamectin chemical treatment, respectively, when the concentration reached to 80 ?g/mL suppressed when 100% of the nematode feeding.4. Under laboratory conditions apply sand column method, determination of the effect of six kinds of insecticides on Heterodera Elachista larvae motion diffusion.The results show: Heterodera Elachista by the different concentrations of profenofos, abamectin, chlorpyrifos and bisultap immersed in a sand column 24 h free agents, which were inhibited diffusion, and the abamectin had the highest inhibits activity; in the lower concentration range, more Heterodera Elachista diffusion of ethoprophos and triazophos has hormesis effect, can stimulate the diffusion of sports nematodes.5. The rice is cultivated in red paddy soil with Heterodera Elachista cysts (150 cysts in 1L soil),15 days after, soil was treated by five kinds of different concentrations of pesticides, including abamectin, profenophos, bisultap, triazophos, chlorpyrifos.10 days after the spraying, the chlorophyll content, the fresh weight of root and Plant fresh weight have been measured, the protective effect of pesticides on rice has been evaluated. The results showed that:After different doses of five kinds of pesticides treatment, the chlorophyll content of rice plants had a significant increase than untreatment blank control, the magnitude of increase was higher than 18%; rice seedlings exhibited fibrous root system decreased and root fresh heavy decline, its root fresh weight decrease 10% or more:rice seedlings aboveground fresh weight were significantly increased, aboveground fresh weight increase rate was over 50%, it showed good protection to rice seedlings.