赤星菌弱毒株孢子制剂PCF1对烟草赤星病的控制作用

本文研究了赤星菌(Alternaria alternata)弱毒株TBA16的灭活孢子制剂PCF1对烟草抗赤星病的诱导作用,及在田间控制赤星病的效果和对烟叶产量、品质等性状的影响。在温室内幼苗上,PCF1可明显诱导烟草对赤星病的系统抗性,抗性诱导效应为57％—89％。在山东5个主要产烟县进行的田间试验表明,PCF1有3种作用:①可以明显控制赤星病的发生程度,效果与用作对比的化学农药菌核净相当或略低,在烟草生长后期防治效果可达76％;②增强烟株生长和叶片扩展能力,使烟叶(烘烤后)产量提高7％—38％;③明显改善烟叶内在品质、增加上中等烟叶的比例,使产值提高17％。

CONTROL OF BROWN SPOT BY INDUCED RESISTANCE IN TOBACCO: FIELD APPLICATION OF 'PCF1' , A PREPARATION FROM CONIDIA OF ALTERNARIA ALTERNATA STRAIN TBA16

The hypovirulent strain TBA16 of Alternaria alternata had been evidenced to be able to induce systemic resistance against brown spot of tobacco. A preparation, named PCFl, was made from the conidia of strain TEA 16 which showed good effect of resistance induction when its different components in structure were tested. On pot-planted tobacco seedlings, the PCFl gave 57% effect of inducing systemic resistance to the disease when two leaves of the seedlings were inoculated by droplet method, and 89% effect when the plants were inoculated by spraying and the strain TBA28 with strong virulence was used as a challenger. The field application of PCFl in 5 counties of Shandong Province indicated that the preparation functioned in controlling brown spot, enhancing plant growth, increasing output and improving quality of cured leaves. The function of disease control of PCFl was mainly by restricting the spot extension, the effect ranged from 25% to 50% at early stage and the best effect of 76% at late stage of the plant growth were observed. For cvs. NC89,NC82 and K326,which were planted in the tested fields, PCFl enhanced growth ability by 5% -17%, increased leaf development by 5%- 7%, and raised output of cured leaves by 7%-38%. The improvement of chemical quality of cured leaves was achieved by PCFl application, which resulted in nicotine reduction from 3. 08%(CK) to 2. 78%, K increase, Cl- decrease, and raise of K/C1 ratio from 0. 6 to 1.1, when 9 parameters in chemical quality were tested.