Study On The Changes Of Chemicals In Damaged Pine Needles And Their Effects On Population Parameters Of Dendrolimus Kikuchii Matsumura

Dendrolimus kikuchii Matsumura is one of significant pine pests in south china. In Fujian province, this pest was serious in high altitude area, and usually with D.punctatus Walker mixed occurrence. The pines were damaged seriously and grew unhealthy in north Fujian where the pest outbroke, and caused the economical ecological of forestry decreasing. This paper study on the D. kikuchii population parameters and biological characteristics,population spatial pattern and sampling technique,changing characteristics of major nutrient and secondary substance in damaged needles,effected to the population characteristics of larvar by fed on the damaged needles, to grasp the development of its occurrence, provide scientific basis for prevention and treatment work. The results are following:1. D. kikuchii Matsumura which occurred lightly in altitude area, completed two generations each year in Fujian province, and overwinters by larvae in the ground cover. The foraging limits of needles were 134-192 for larvare. The larvae is 7 generations, less 6 or 8. The larva period,pupal period,egg period were 86-102d,28-37d,6-10d separately in the first generation, 198-223d,31-43d,8-12d deparately in the second generation. The female and male compare about 0.48 in the first generation, second is 0.51.One female deposited 63-148 eggs, and lay on the needles together.2. The spatial distribution patterns of D. kikuchii larvae was congregating distribution in the forest. The basic ingredients of distribution are individual groups, individual and mutual attract with each other. The controlling index is 10 pests in every pine, which making index according harm condition,economic loss indices and the controlling index of pine caterpillar in the 5 year old pine forest.3. Contents of flavonoid, tannin and total phenols in damaged needles were higher than undamaged, while tannin and total phenols showed a decreased trend with the aggravation of damage degree. Contents of soluble sugar, polysaccharide and protein in damaged less than undamaged, Results showed by variance analysis that the contents of nutrient were significant differences between damaged and undamaged.4. Slower development, lighter weight, less appetite, less fecundity, high mortality as the larvae fed on needles of damaged trees. The study also showed that there were relevant between periodic outbroken of D. kikuchii and contents of nutrient and secondary substance in damaged needles.