The Effective Accumulative Temperature Forcasting Model And Genetic Diversity Of Homoeosoma Nebulellum

The developmental threshold temperature and effective accumulative temperature of Homoeosoma nebulellum have been determined. Dynamic of adult population of Homoeosoma nebulellum and meteorological data was combined with to build up forecasting model of occurrence period, in order to provide the supported data for scientific measures of integrated control. At the same time, for the sake of finding out the genetic relationship in different geographic populations of Homoeosoma nebulellum from Inner Mongolia, Xinjiang and Ningxia, mtDNA COI molecular marker was used to study on genetic diversity.The results including:1. By Observed the developmental duration of Homoeosoma nebulellum under the four temperatures of 24 ℃,27℃,30 ℃, and 33 ℃, and recording the developmental period to calculating the developmental threshold temperature (DTT)and effective accumulated temperature (EAT).The results showed that developmental duration were positive correlation with temperature. The developmental speed very significantly linearly correlated to the temperature. The developmental threshold temperatures (DDTs) of the Homoeosoma nebulellum eggs, larvae, pre-pupae, pupae and whole generation were 14.31℃、8.07℃、18.27℃、12.2℃ and 11.11℃,respectively. The effective accumulated temperatures (EATs) of each stage were 45.13d· ℃、328.42d·℃、12.97d· ℃、 140.54d·℃ and 500.00d·℃ respectively.2. By investigating the adult population dynamic of Homoeosoma nebulellum in the field, and comparing with the developmental threshold temperature and effective accumulated temperature on the experimental conditions, the average effective accumulated temperature that from the first adult appearance to the overwintering generation trapping peak was 538.7±39.7 degree-day by calculated. The average cumulative effective accumulated temperature of the Homoeosoma nebulellum which is suitable for the growth was 1585.2±89.5 degree-day in Bayannur Linhe district in each year. By calculating the occurring generation, the results shows that the generation number occurred was about 2.5 in Bayannur. It was agreed with the observed results in the field. The cumulative fraction of adult catches have Logistic increased with the effective accumulated temperature growth clearly. The forecasting model of Homoeosoma nebulellum adult occur period was built based on above results.3. By observing the productivity and mortality of Homoeosoma nebulellum whole stages under the four different temperatures of 24 ℃、27℃、30℃ and 33℃, the experimental population life table on the different temperatures was obtained finally. The experiment shows that the mortality of egg was highest in the whole stages was 0.689, 0.613,0.600 and 0.400, respectively. And larva was the second highest which was 0.429, 0.355,0.427 and 0.625, respectively. The mortality was lower after the mature larva to the pupal period. It was obvious that the young stage of insect was the most sensitive with the environment and the better stage take measures of prevention.4. After 337 mitochondrial cytochrome oxidase subunit I (COI) gene sequences in the 14 different populations of Homoeosoma nebulellum was analysised,32 mutation sites was found which accounts for 5.62% approximately. In the replace of whole nucleotides sequence, the transitions occurred 99.72%, while the transversions occurred 0.28%, the total transitions and transversions bias radio R was 338.663. Within 37 gene sequences of 13 populations obtained,21 haplotypes was defined, and the total haplotypes diversity index was 0.696. The nucleotide diversity was in the range of 0.00035-0.00281 in the intra-population, and the average value was 0.0008. Neutrality test for each populations of Homoeosoma nebulellum shows insignificant in the most majority of tests. The results of Analysis of Molecular Variance (AMOVA) shows that the variance components in different geographic populations was 1.99276, while the variance components was 0.38859 in the intra-population and have significant difference.