Studies on micropore film to control tobacco aphid-borne virus diseases
Tobacco virus diseases have been among the main factors hindering tobacco production in China. The effective control method for the dominant tobacco aphid-borne viruses including PVY and CMV is to prevent alate aphids migrating into tobacco fields. Micropore film was developed to control aphid-borne virus diseases and two years of tests showed the perfect control effect. In 2002 and 2003, the experiments were carried out in Changle county, Pingyi county, Yishui county and experimental farm of Tobacco Institute of CAAS. Micropore film was covered on the ridges in field after seedlings transplanted and uncovered after aphids migration period according to status of tobacco plants. Micropore film covered in field could control tobacco aphid-borne virus diseases perfectly. The results in 2002 showed that control effect was 12.1%-100% five days after micropore film uncovered and 14.9%-100% fifteen days after micropore film uncovered. The results in 2003 showed that control effect was 48.37%-90.74% five days after micropore film uncovered and 18.39%-90.49% fifteen days after micropore film uncovered. Disease severity increased and control effect decreased with time prolonged after micropore film uncovered. In the field covered with micropore film, output was increased 3.0-11.9 kg (2.37%-11.9%); production value was increased 87.1-139.9 yuan (RMB)(9.96%-13.7%); percentage of classy tobacco leaf was increased 2.6-7.5; average price was increased 0.17-0.50 yuan (RMB). These results showed that micropore film could be applied to control tobacco aphid-borne virus diseases in tobacco field. In the field covered with micropore film, output, production value and percentage of classy tobacco leaf were increased and Tobacco plants became strong. The tobacco quality difference between field covered with micropore film and uncovered with micropore film was not significant. Covered with micropore film on the ridges after tobacco seedlings transplanted can prevent alate aphids from migrating into tobacco fields, and therefore tobacco aphid-borne virus diseases can be controlled effectively. Two years of results in four places indicated that covered with micropore film is a economical and effective method for controlling tobacco aphid-borne virus diseases. When applying micropore film, attention should be drawn to the followings: (1) Produce virusless tobacco seedlings; (2) Tobacco field should be covered with micropore film throughout migration period of alate aphids and uncover it after migration period; (3) Rip the micropore film 5-7 days before uncovered. In this way, tobacco plants can adapt to the change of temperature and humidity.