Evaluation On The Control Of Arceuthobium Sichuanense In Qinghai Xianmi Woodland

Arceuthobium sichuanense is a unique multi-year parasitic seed plant in China,the main infection of Qinghai spruce,Picea wilsonii and other spruce species,It makes the host branches produce broom-like branches,make the trees die.So that the current serious harm to Qinghai spruce forest,the most difficult to control one of the major diseases.In order to effectively control its propagation and spread,In this paper,we used the chemical control methods such as 1:200 ethephon spray on the dwarf mistletoe budding and flowering and 1:50 ethephon infusion,different pruning treatments to control spruce dwarf mistletoe analyze the control effect and evaluate the safety of the host spruce and seeds,provide theoretical support and popularization experience for large-scale application of ethephon and pruning treatments to control spruce dwarf mistletoe.The main findings are as follows:(1)Spraying 1:200 buds and flowering at the flowering stage of spruce dwarf mistletoe have control effect.The results of one time spray in the buds showed that the branche control effect was 41.93%,and the rate of seed relative yield reduction was 45.24%.The results of one time spray on the flowering showed that the branche control effect was 39.47%,and the rate of seed relative yield reduction was 45.12%.Two times spray on buds and flowering can improve the control effect.On the buds the control effect of the dwarf mistletoe on branche can be increased to 81.42%,The rate of seed relative yield reduction can be be increased to 78.08%.On the flowering the control effect of the dwarf mistletoe on branche can be increased to 81.62%,The rate of seed relative yield reduction can be be increased to 60.16%.(2)1:50 ehtephon infusion have control effect.The average control effect on branche was 50.14%.The rate of seed relative yield reduction was 43.45%.(3)We used 1:200 ethephon spraying and 1:50 ethephon infusion to control spruce dwarf mistletoe,the viability of spruce seeds showed that:There were no significant differences in the external traits of the spruce and the seeds compared with the control group after spray Treat with spraying on buds the germination rate of spruce was 35%,the germination potential was 23.3%,the germination index was 2.01 and the viability was 36.67.Treat with spraying on flowering the flowering the germination rate of spruce was 35.83%,the germination potential was 28.17%,the germination index was 2.06 and the viability was 32.5.Treat with infusion the germination rate of spruce was 32.5%,the germination potential was 25%,the germination index was 2.31 and the viability was 32.5.(4)Pruning treatment can not reduce the damage rate in the forest of spruce dwarf mistletoe,but can reduce the incidence index,reduce the degree of harm.The incidence index of forest that repair 1/3 crown was 47.3%lower than that before of pruning,and The incidence index of forest that repair 1/2 crown was 26%lower than that before of pruning,and The incidence index of forest that according to the different degree of tree disease and take different pruning strength was 47.3%lower than that before of pruning.