Study On Wintering Habits, Light Response And Indoor Screening Of Insecticides Of Rice Water Weevi

Rice water weevil(Lissorhoptrus orgzophilus Kuschel)is a quarantinable pest in China,with strong reproductive capacity,wide spread area and wide host range.After being damaged,the rice field yield decreased by 20%～30%,and the yield decreased by more than 50% or even no grain was harvested in the heavy occurrence area.In this study,the rice water weevil in Dongning County,Heilongjiang Province as the main research object,and the distribution of rice water weevil adults in different wintering sites and feeding rhythm under different conditions were investigated.The sensitivity of rice water weevil to different monochromatic wavelengths and its tendency response to computer simulated mixed color plates were studied.Eight insecticides were screened in laboratory to provide a reasonable basis for comprehensive control of rice water weevil.The results are as follows:1.The survey of wintering sites of rice water weevil showed that the main wintering habitats of rice water weevil were forest belts and hillsides near rice fields,followed by ditches.No wintering adults were found in ridges between rice fields and between rice fields.The soil was loose,and it was suitable for rice water weevil adults to overwinter on the surface and in 0～5 cm soil layer.In order to reduce the overwintering base of the adult weevil,the weevil should be intensively eradicated and destroyed in the forest belt,hillside and irrigation ditches near the rice field.2.Through the investigation on feeding rhythm of rice water weevil adults,it was found that the feeding behavior of rice water weevil adults fluctuated during the day,and there were 3 feeding peak periods,which were 10:00～12:00,16:00～18:00 and 20:00～22:00 respectively.When the temperature was 30°C and the light condition was dark,the food intake of rice water weevil was the largest.3.Through the results of the shift of the chemotactic response and the phototaxis rate of the rice water weevil under different monochromatic light stimuli,the adult rice water weevil has better phototaxis to the orange light of 620 nm and the blue light of 420 nm.The displacements reached 26.29 cm and 23.52 cm,and the phototaxis rates were both above 90%.The results of the determination of the chemotactic response of the rice water weevil to the computer-simulated mixed color showed that the orange mixed color plate(620 nm)and the blue mixed color plate(420 nm)had the best trapping effect on the rice water weevil.4.The screening results of 8 insecticides showed that 48% thiamethoxidin suspension and40% triazophos emulsion had the best control effect on rice water weevil overwintering adults and were recommended to be used.