The Population Dynamics About Two Pests Of Rice And Their Natural Enemies In Nanning

Rice is one of the main food crops in China." Two-Migratory Rice Pests" refer to Cnaphalocrocis medialis and delphacids.Sogatella furcifera and Nilaparvata lugens are Two-Migratory Rice Pests.Guangxi Province is an important gateway for the Two-Migratory Rice Pests into China.An equipment has been set up to trap insects in different period of time at the Institute of Plant Protection of Guangxi Academy of Agricu,it can effectively trap the aerial population of insects in Xixiangtang,Nanning,Guangxi.Number of Two-Migratory Rice Pests field in the Guangxi Academy of Agricu can be monitored by this equipment.After SPSS significant analysis,analysis of meteorological background and migration trajectory through HYSPLIT platform and GrADS,ArcGIS,the following conclusions are drawn:(1)Analysis of variance(α=0.05)showed that the average number of attractants in June and October 2016 was significantly more than other months.The average number of attracting species in May was significantly more than other months;the average number of attractants in June 2017 was significantly more than other months.The average attractant species in May and June was significantly more than other months;the number of insect species under the lamp in May and September 2018 was significantly different from other months,and the number of species was similar to 2016 and less than 2017.The number of light-trapping insects in September 2018 was significantly different from the other months except April,and the number of insect catchers was significantly lower than in 2016 and 2017.There are significant differences in the number of attracting species and the number of attractants at different period of times in 2016-2018.The average number of traping insects in the three periods from 19:00 to 20:00,20:00 to 21:00,and 06:00 to 07:00 in 2016 is significantly more than other periods;The average number of attracting species at 19:00-20:00 and 06:00-07:00 is also significantly more than other times.During the period from 19:00 to 20:00 in 2017,the average number of traping insects and the average number of attracting species are significantly more than other periods;the average number of traping insects and the average number of insects from 19:00 to 20:00 are also significant in 2018,which more than other periods.(2)In 2016,the period of migratory peak of C.medialis was in June,and the peak of the migration in 2017 appeared in mid-May to early July.In 2018,the period of migratory peak took place from mid-September to mid-October and mid-November.the trapping amount of C.medialis in 2018 was significantly less than 2016 and 2017.The amount of light-traping in different generations of C.medialis is different.Number of the third generation of C.medialis in 2016 is significantly more than 2017,but the number of the third generation of C.medialis in 2016 and 2017 are significantly more than other generations.In 2018,the sixth and eighth generations of C.medialis were more than other generations.The immigratory peak of C.medialis in the first half of the year:In 2016,the amount of C.medialis was concentrated at 22:00-4:00,of which the amount of light reached at 0:00-1:00,2:00-3:00 is 15.2%and 14.8%respectively.in 2017,the amount of light-traping of C.medialis was concentrated at 19:00-20:00 and 1:00-4:00,of which 19:00-20:00 is the most,accounting for 12.9%.The emigratory peak of C.medialis in the first half of the year:In 2016,the amount of C.medialis was concentrated at 5:00-7:00.The amount of reached in 5:00-6:00 and 6:00-7:00 is 21.1%and 22.9%respectively.In 2017,the largest amount of light-traping was concentrated at 19:00-20:00,accounting for 32.9%.The emigratory peak of C.medialis in the second half of the year:In 2016,the amount of C.medialis is concentrated at 3:00-7:00,,The amount of light reached at 3:00-4:00 and 6:00-7:00 is 15.2%and 14.8%respectively.In 2017,the largest amount of light-traping was concentrated at 19:00-21:00 and 6:00-7:00,of which the amount of light reached at 20:00-21:00 and 6:00-7:00 is 17.1%and 24.2%respectively.(2)The amount of the second and third generations of the S.furcifera in 2016 and the amount of the second,third and fourth generations of the S.furcifera in 2017 are significantly more than other generations.In 2018,the second,third and sixth generations of S.furcifera are also more than other generations.In 2016,the amount of the seventh generation of N.lugens is more than the other months,and the amount of the third generation of N.lugens in 2017 is more than other months,which developed more severe.In 2018,the amount of the sixth generation of N.lugens is more than the other months,but the amount of insects was less and the damage was lighter.From the time of the light-traping period of the delphacids in 2016-2018,most of the delphacids took off at dusk and at sunrise,it means the amount of insects is more than others at 19:00-21:00 and 6:00-7:00.(3)According to the the migration trajectory of delphacids,the S.furcifera in the first half of Guangxi Nanning in 2018 mainly came from the southwestern rice region of Guangxi,the north-central rice region of Vietnam,the north-central Laos,and the northern rice region of Thailand.When moving out,it entered the southwestern part of Guizhou from northwestern Guangxi or northwest,and further entered the southwestern and the western part of Hunan Province.(4)In the first half of 2018,the trajectory in the immigratory period of N.lugens has some error in Nanning,Guangxi.In the first half of the year,they moved into Guizhou Province along the edge of Guangxi and Yunnan provinces,directly into Yunnan or along the borders of Yunnan and Laos,some entering Yunnan,some entering Laos in the emigratory period.The N.lugens moved from the Hunan Province in the immigratory period during the second half of 2018,and the trajectory of the emigration period reached the Taiwan Strait along the Hunan-Jiangxi-Fujian Province.(5)Based on the data of 2016-2018,the natural enemies of the rice planthopper,such as Cyrtorhinus lividipennis Reuter,Coccinellidae,Braconidae and the Neuroptera,which coincide with the light-traping peak period of the rice planthopper.However,the light-traping peak period of the Staphylinidae is in August,when the early rice had been harvested and the late rice has just been transplanted in Nanning,Guangxi.Therefore,the insect source may come from the habitat out of the rice field.in addition,the Cyrtorhinus lividipennis Reuter and the C.medialis have obvious accompanying migration.