Studies On Occurrence Regularity And Integrated Control Technology Of Tobacco PVY Diseases In Ningxiang

In recent years, tobacco PVY diseases has increased in Ningxiang County of Hunan Province and become one of the main diseases causing severe losses to tobacco leaf production. Although many measures have been carried out, the effect is not satisfactory. Therefore, it is urgent to explore and establishment effective integrated control system of tobacco PVY diseases to reduce losses and promote sustained and healthy development of tobacco leaf production. The occurrences regularity of tobacco PVY diseases in Ningxiang has been discussed and the effect of several control methods for tobacco PVY diseases has been studied in this paper through the methods of combining the field survey and field experiment. According to the conclusions, this paper develops a comprehensive prevention and control measures of tobacco PVY disease. The main results are as follows:The occurrences of tobacco PVY diseases in Ningxiang has a close relationship to the plant varieties, cropping systems, the environment of tobacco fields, tobacco growth period, the number of aphids and other factors. Currently the plant varieties do not have a strong resistance to tobacco PVY diseases in Ningxiang. The tobacco field which the previous crops are tomato and pepper has a higher incidence of diseases than the tobacco field which the previous crops are rice and rape. Tobacco-rice Rotation should be the first choice for the farming systems. The tobacco field environment which is far away from the potato field has a higher incidence of diseases than the tobacco field environment which is near the potato field. The incidence of tobacco PVY diseases is different as the tobacco at different growth stages. At seeding stage, tobacco is rarely infected by tobacco PVY diseases. But at rosette stage, tobacco begins to be infected.At vigorous stage and after topping stage, tobacco is serious infected by tobacco PVY diseases. The incidence of tobacco PVY diseases has a close relationship to aphid. There are two peak periods about aphids moving into the tobacco field, one is in late April, and the other is in late May. The incidence of tobacco PVY diseases increase is primarily caused by the first large-scale moving into tobacco field of aphids. The incidence and disease index of NC55are only6.67%and2.22.It has a strong resistance to tobacco PVY diseases. Rational use of agricultural control measures has a good control effect. The field which agricultural control measures are well implemented has a lower incidence of diseases than the field which agricultural control measures are failed to perform well. Efficacy trials form the ten kinds of chemicals show that:Virus Special has the best control effect on tobacco PVY diseases, the average control efficiency is64.66%,Followed by medium eliminate emulsion、HOPE and The Virus Will g. Field experiment from this four kinds of chemicals show that:the average control efficiency of the four kinds of chemicals is higher than50%, Virus Special has the best control effect, the control efficiency of the other three kinds of chemicals is consistent. Three kinds of anti-aphid measures for tobacco PVY diseases has good control effect, The combination of putting Aluminum reflective film on field and using5%imidacloprid EC has the best control effect.