Study On Occurrence Regularity,Precention And Control Of "Two Migration" Rice Pests In Hechi

Rice planthopper and Cnaphalocrocis medinalis,referred to as “two migration” pests,can move away with the air flow,are main insect pests of rice production in China,which have caused serious losses to rice production in China in recent years.Hechi is located in the northwest of Guangxi,with rice as the staple food crop and the average annual rice planting area is about 1.5million mu in recent years.However,due to the acceleration of urbanization,the reduction of rural labor force,the strategic adjustment of the agricultural industry structure,and the expansion of silkworm and fruit planting area,rice planting area have undergone relative decrease in recent years.What’s worse,combined with the damage caused by diseases and insect pests,the rice production has been threatened over the years.In order to better summarize the occurrence regularity of "two migration" rice insect pests in Hechi,and improve the monitoring technology of "two migration" insect pests,the light traps and field surveys were used to study the occurrence and damage of "two migration" rice insect pests in Hechi,and the control countermeasures were put forward according to the local conditions.The results were as follows:(1)The migration time of rice planthoppers is relatively early with high frequency of migration peaks.The migration usually starts in March,with the earliest migration time of March 1 in 2010,2013 and 2016.Rice planthoppers can occur 7-8 generations a year in Hechi,with overlapping generations,of which the second to sixth generations are the main insect pest generations.The occurrence of rice planthoppers is high every year,and the occurrence area is large.Generally,the damage caused by rice planthoppers in the middle and late stages of the early and late rice growth is relatively serious and the prevention and control of it is very difficult.(2)The migration time of cnaphalocrocis medinalis is later than that of rice planthoppers,from mid-to-late March to early April.It occurs seven to eight generations a year,the second and third generations have the widest range and the highest occurrence frequency.Among them,the third generation has the highest density of insects in the field at peak period.Since the rice leaf roller can move away with the air flow and can not overwintering in Hechi rice area,there are few moths induced under the lamp before the middle of April of each year,and no harm is found in the field.The second generation of adult pest move in in the upper and middle of May.The migration time of them related to the climatic conditions.Generally,they migrate earlier in the year with the high temperature,high frequency of wind and rain weather in spring,and vice versa.The fourth generation pest have mainly caused damage in the middle rice areas in Hechi in recent years.The fifth generation pest occurred rarely.The sixth generation pest is the main damage of late rice production.(3)There are four commonly types of Hechi two migratory pests prevention measures: agricultural control,physical control,chemical control,biological control.Hechi City have also adopted comprehensive control measures such as promoting land circulation to promote unified control,strengthening exchanges and cooperation among grass-roots plant protection stations,increasing propaganda and guidance,increasing insect coverage and popularizing the application of green control technology.