Varity Identification And Control Techniques Of Orobanche Spp. On Tobacco In Baicheng Area,jilin Province

As an important disease in tobacco production,broomrape is often regarded as a pernicious parasitic malignant weed,the tobacco plants parasited and damaged by broomrape are dwarfed,the leaves become thinner,and the yield and quality of tobacco are seriously reduced.The seeds of broomrape are is small in size,large in quantity,fast in propagation,can survive in soil for more than ten years,and under the suitable condition,can sprout in the whole growing season of tobacco,the prevention and control of broomrape are very difficult in production,which becomes an important factor which limits the production and development of tobacco.At present,the methods of manual pullout,application of herbicide,crop rotation and broomrape-resistance breeding are often used,their control efficacys are not obvious,and are limited by many factors,so it is urgent to explore the efficacyive methods to control broomrape in tobacco.This study aims to find efficacyive control methods and lay the foundation for the control of broomrape in the fields and reduce damage of broomrape on tobacco,based on the identification of species and varities of Orobanche,systematic research was carried out in chemical control,soil treatment and other aspects of broomrape.The results of this study are as follows:1.The identification of Orobanche in tobacco.Using morphological identification method we identified the species of broomrape on tobacco in Baicheng area,they are Orobanche cernua and O.cernua var.hansii.ITS sequence can not be used to distinguish the two varities of O.cernua.This is the first report about different of O.cernua at variety level,which occurred on tobacco,and it is also the first report that O.cernua var.hansii parasiting tobacco in Jilin province.2.The study of the chemical control of broomrape in tobacco.This study confirms that on the prevention of broomrape,the control efficacy of soil treatment herbicides are better than those of leaf treatment.In the soil treatment herbicides,metolachlor 72%EC at 125?150m L/m~2has the best control efficacy,the average plant and fresh weight control efficacy are65.40?77.21%and 81.87?83.28%.In the leaf treatment herbicides,rimsulforon 25%WG at5?5.5g/667m~2 has the best control efficacy,the average plant and fresh weight control efficacy are 54.92%?63.74%and 47.08%?80.80%.It is the first report that metolachlor can be used to control broomrape in tobacco.3.The study of the control efficacy of different soil treatment substances on tobacco broomrape.In the soil treatment substances,sulfur and two kinds of mushroom bran don't have obvious control efficacy to the broomrape,and sulfur can increase the number of broomrape.Vinasse has the best control efficacy,the average plant and fresh weight control efficacys against broomrape were 62.73%?74.16%and 42.70%?66.03%,respectively in 2018,and57.10%?64.17%and 53.23%?80.56%,respectively in 2019.Futher more vinasse can promote the growth of tobacco leaf and improve the yield and quality of tobacco leaf.It is the first report that sorghum vinasse can be used to control broomrape in tobacco.