| Since the 21st century,there have been frequent outbreaks of paddy pests(rice planthopper and rice leaf folder)in Asia,which has become a huge threat to rice production safety.The two migration of rice insects have characteristics such as long-distance migration,abruptness,fulminating and being destructive.Guangxi acts as the main portal of initially move into mainland of China,the situation of the pest outbreak plays a big role on the pest forecast and prevention and control strategy in other paddy growing areas.Nanning city is a representative city of Guizhong area,the study on its air population and the seasonal change rule can provide scientific evidence to the long distance prediction and source management of the two pests.Technical support can be made for natural enemy pest control through studying the seasonal population dynamics of the natural enemy in the paddy.In this paper,searchlight-trap machine equipment with automatic sampling according to time was used in 2016 to make the systematic observation to the pest migration behavior in Guizhong area with Nanning as a representative,as well as the observation to population dynamic of the natural enemy.Rhythm of various insects flapping to lights has been made clear and the source of two pests in guangxi padding growth as well as the population characteristics and dynamics have been demonstrated.This study has achieved several outcomes as follows:According to the result of high altitude searchlight trap in Nanning,Guangxi region,2016,the insect species and quantity changed significantly with the seasonal change.Compare the insect species in different months,we found that the amounts in March and December are much lower than other months.Compare the quantity,we observed that the quantity in March,April and December were significantly lower than other months (P<0.05).The differences of insects quantity can be obvious in different time periods,the quantity captured during 19:00-21:00 was much higher than 21:00-05:00(P<0.05).There was no significance difference in terms of insect species in different time period(P>0.05).There are obvious seasonal changes when the pests and natural enemies like cyrtorhinus lividipenn are exposed under detective light trap.There is a significant difference in terms of average trap quantity in different months(P<0.01)· The population dynamics of rice leaf folder,white-backed planthopper and brown planthopper is similar as that in the air and there are obvious sudden rise and drop.The quantity of rice leaf folder and field moth are larger than late rice moth with the second and the sixth as the domain prevention generation.The quantity of white-backed planthopper early rice light and field moth are larger than early rice moth with the eighth as the main generation.The occurrence quantity of white-backed planthopper early rice and late rice field are the most during illering stage and jointing stage.The occurrence quantity of brown planthopper concentrated in late rice ripening period and harvest.Rice leaf folder second and third generations take a priority to outer move-in,the fourth generation mostly emigrates,the sixth generation is mainly locally breed with other part of the immigration,the seventh generation is also mainly locally breed with part of emigration.White-backed planthopper(2,3,6 generation)take a priority to outside immigration.Brown planthopper is locally breed,the 8th generation is mainly locally breed with other part of emigration.During the observation period using high altitude detecting lights,except from 21:00 to 22:00,from 06:00 to 07:00 and from 19:00 to 20:00,Cnaphalocrocis medinalis Guenee ’s gender component differences between other periods of time and from 19:00 to 20:00 make sense in statistic(p<0.05).Except from 20:00 to 21:00 and from 19:00 to 20:00,sogatella furcifera’s gender component differences between other periods of time and from 19:00 to 20:00 make sense in statistic(p<0.05).Brown rice planthopper’s gender component differences among from 03:00 to 04:00,from 04:00 to 05:00,from 05:00 to06:00 and from 19:00 to 20:00 make sense in statistic(p<0.05).No significant light rhythm in morning twilight bimodal type is shown among those light-flapping huge peak day and peak-day rice leaf folder,white-backed planthopper and brown planthopper.Seven species of natural enemy insects like Cyrtorhinus lividipennis had a very obvious difference(P<0.01)in different months concerning their average trap quantity in 2016.Significant phenomenon of accompanying migration came out among species such as cyrtorhinus lividipennis and brown planthopper.There was a significant positive correlation between trap-quantity and occurrence quantity in the field under the detecting light. |
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