Migratory Biology and Population Dynamic of Cnaphalocrocis Medinalis (Guenèe)
|School||Nanjing Agricultural College|
|Course||Agricultural Entomology and Pest Control|
|Keywords||Leafroller Population dynamics Re-migration capacity Trajectory analysis Occurrence mechanism|
Leafroller is one of the important insect pests of rice growing areas in Asia. Because of its long-distance migratory characteristics of the population occurred on rice infestation with sudden, in our country since 2003, year after year nationwide, it is necessary to further understand its population variations in migratory behavior. In this study, the field surveys, laboratory experiments and numerical simulation combined years of historical data and reanalysis, clear leafroller Re-migration capacity, the system studied leafroller population dynamics in Waseda The Spring May and as the representative of the Chinese mainland to Nanning main move into the the migratory trajectory and Insect land on behalf of immigration from abroad. The main conclusions are as follows: April-June 2007 in the Guangxi Academy of Agricultural Sciences, Waseda system to catch the moth and female moths ovarian anatomy results show that leafroller 3-4 generations can occur in Nanning Waseda. The first generation of April to early May, a very small amount of local wintering Insect but typical major move into generations. Second generation in early May to late May, a small local breeding Insect, but most of the field moved into. The third generation of the end of May to June, mainly to move out on behalf of the and stranded local hazards, but there is still a small part. The leafroller population is divided based on the accumulated flight time of the indoor simulation hanging flight test measured residence type (lt; 40min), migratory type (≥ for 40min ~ 5130 min) and strong migratory type (gt; 130 min ) three types; frequency and the three types of individuals were 46.09%, 27.34% and 26.56%, respectively. Residence average accumulated flight time of 11min, the migratory type for 82min, the strong migratory type 232 min, three types of flight time difference was very significant. Leafroller moth and the male and female adults of different ages, flight reproductive isolation, no significant differences in the average time of flight of the male and female worms were 78.53 ± 10.71 min and 86.23 ± 14.01 min. The adult mainly active flight the first six hours after flight were significantly lower in the flight the proportion of individuals and the ability to fly. Re-migration simulation experiment to prove the the leafroller existence of a strong Re-migration capacity, its population for a migratory individual frequency more than about 90%, 2 Re-migration rate of more than 70%, three times nearly 50%, about 30%, about 5 times up to 15%, up to 9 times (days). Adult sex and food on the Re-migration frequency did not significantly influence the migration capacity, honey water can promote the migration capacity and the development of ovaries. Through the systematic investigation of the 2007 field the female moths system anatomy, trajectory analysis the synoptic background analysis of a case, on May 8, May 21, the two main the immigration peak day ,700-1500m 5 height and 1-5 times (days) the migratory trajectory analysis results show that: 2007 Nanning area leafroller May the Lord to move into the peak of the main Insect for the the Guangxi Nanning ← northern Vietnam (N: 21.3 ° -21.91 ° E: 106.84 ° -104.49 °) [Re-migration (days) ← northern Thailand (N: 17.18 ° -18.61 ° E: 104.72 ° -100.04 °), north-central (N: 18.95 ° -20.36 ° Laos , E: 105.28 ° -100.87 °) [Re-migration (days)] ← - central Thailand (N: 15.01 ° -16.75 °, E: 105.78 ° -99.80 °) [Re-migration 4 times (days)] . Peak and peak day occurred, and the occurrence of the amount by two different time periods 1970-1980 and since 2000 in Nanning, Guangxi leafroller early immigration move back (d, May) and autumn (September and October) compared and analyzed from 1981 to 2002 and the relationship between rainfall, rain days between the two periods, with early immigration since 2003, found that insect source early immigration abroad doubled since 2003, and fall to move back early ( advance from mid-September to early September) is resulting in Nanning leafroller to the King occurred mainly due to successive years of large, early move into the fall is not necessarily linked to move back in the amount of time and the occurrence of insects.