Effect Of Monochamus Alternatus On The Content Of Chemical Materials In Needles & Study On The Dispersal Pattern Of It's Adults

Monochamus alternatus is a main insect media of Bwsaphelenchus xylophilns. The pest mainly feeds on the pines, which grow poorly. In Fujian province, the pest distributes generally and it often breaks out causing serious damages in some areas. At present, the biological, ecological characteristic and integrated management of the pest were studied systematically in our country. The results of these researches were reported. The integrated management based on these researches was applied to control the pest. In some areas, the pest's population was controlled effectively, but the Bursaphelenchus xylophilus has spread rapidly in recent years. This phenomenon proves that lots of questions still exist. So it is necessary to combine the realities of Fujian Province, develop the research of the relationship between the pest and the pine and study on the dispersal pattern of the adults. Base on these researches, we will offer the effective technological measures and ecological strategy to control the pest scientifically. By the control of the break out of the pest we would prevent the spread of the Bursaphelenchus xylophilus effectively. The main results were summarized as follows:1. Chemical materials in the damaged pine needles were analysed in this paper. The results indicated that with the pine was damaged by adults and larvae of Monochamus alternatus, the contents of secondary metabolites (Tannins and Flavonoids) were changed constantly, which increased at first and descended later. On the contrary, the nutrient substances (water-soluble sugars and total sugars) descended at first and increased later. There are different changes of 17 amino acids in the needles of the damaged pines. In the needles of damaged pines, the mineral elements (nitrogen, phosphorus and potassium), the nitrogen increased at first and descended quickly later. The potassium increased largely. With the different degrees of damages by the pest, the pines reactions are constantly fluctuating. Also, it's different by adults and larvae. By larvae, the change is indistinctive. But by adults, the change is distinct. With the co-evolution with the insects, the pine adapts to different stages of the pest.2. The dispersal pattern ofMonochamus alternatus adults was studied in Shaxian County by the mark-release-trap method. After studying the dispersal parameters have been worked out, the dispersal models were built. The results indicated that the adults' population presented normal distribution from the estimation of deviation; the dispersal rate decreased with releasing time. The dispersal density reduced along with the increment of distance and duration; the population average dispersal distance was 123.25 m, Analysis of dispersal reasons showed that the dispersion was brought about by environment elements, especially by density independence factors. The dispersal pattern was influenced by wind velocity and direction, and had much relation with relative humidity, stands, slope directions, shade density and precipitation, but little with positions of slope.