Degradation Characteristics And Rejuvenation Technology Of Dastarcus Helophoroides Fairmaire

Dastarcus helophoroides Fairmaire is an important and effective dominant host for the prevention and control of Monochamus alternatus Hope.In recent years,the technology of the artificial mass breeding of D.helophoroides Fairmaires in our country is more and more mature.The field prevention and control technology of M.alternatus Hopes is becoming mature gradually.This has given us great confidence,because it means that the biological control means of large-scale release of D.helophoroides Fairmaires can be realized to prevent and control M.alternatus Hopes in the future.When cultured under laboratory conditions,the phenomenon of collective degeneration of the population is almost inevitable for natural organisms.In laboratories,substitute hosts are used chronically for the mass rearing of D.helophoroides Fairmaires.However,after many generations,the application ability in forest,parasitic ability and survival activity of D.helophoroides Fairmaires are all decreased.Breeding many generations continuously under laboratory conditions with the same host chronically will not only reduce the vitality of the whole population,but also have an effect on the artificial mass breeding of D.helophoroides Fairmaires.In this article,we first discussed the degeneration trend of artificial breeding of D.helophoroides Fairmaires under indoor conditions.The experiment objectives are adult weight,fecundity,hatching rate,parasitic eclosion rate and winter survival rate of parasitism.By observing the degeneration process of the first,third,sixth,ninth,twelfth,fifteenth and eighteenth generation of D.helophoroides Fairmaires,we find out that the body weight,fecundity,hatching rate,parasitic eclosion rate and winter survival rate of parasitism of these adults don't have significant differences before the fifteenth generation.There is significant degeneration in the eighteenth generation.Secondly,the eighteenth generation of D.helophoroides Fairmaires which have significant differences are used as the matrix to conduct the study of rejuvenation technology of D.helophoroides Fairmaires with three methods: changing the feeding content of D.helophoroides Fairmaires,performing back inoculation on the natural hosts of D.helophoroides Fairmaire and the simulation of natural conditions.The obtained conclusions are as follows: The adoption of back inoculation on the natural hosts or change of food can achieve the rejuvenation of the degenerated population quickly.While the physique of D.helophoroides Fairmaires in field exercise experiments is significantly increased,and it's simple and quick operation mode which is easy to operate enables it to become an important way of the rejuvenation of D.helophoroides Fairmaires.It is generally believed that due to the influence of genetic factors,if insects are fed indoors continuously for a long time,especially some insects are fed with artificial diets for a long time,the survival state of these populations is bound to be affected by varying degrees,and a decline trend will appear.The source of laboratory insect populations is relatively narrow and the food is relatively simple,and many generations are bred under continuously substantially constant conditions.All these resulted in the overall decrease in body weight,fecundity,and survival rate.Thus,the vitality of the whole population may be recovered to a certain extent by replacement of natural feed,back inoculation on the natural hosts or simulation of natural conditions.