The Occurrence Regularity Of The Powdery Mildew Of Landscape Plants In Nanjing And Studies On The Technique Of Chemical Control

The dissertation make an extensive investigation on the powdery mildew of landscape plants in Nanjing.The research about the occurrence regularity and chemical control of the powdery mildew of Folium mahoniae and Plantnas has been carried out.The main results are listed as follows:The investigation of the powdery milew of landscape plants in Nanjing are carried out.It is found that there are twenty six landscape plants are infected.There are fifteen pathogens have been identified and their speci names are determined.Other eight pathogens are identified by their asexual spores.The research about the powdery milew of Plantnas are carried out,the result shows that the primery infestation occurs in June in 2008,and the infection becomes slowly in rainy season,and reach epidemic stage again in autumn. Plantnas growing in bad environment and weak growth vigor are infected seriously.The pathogen is molecular identified as Erysiphe platani.The suitable temperature for the conidia germination is 20 to 28℃,the suitable humidity for the conidia germination is 25%～100%,the lifetime of the conidia is thirteen days.The investigation of Folium mahoniae powdery mildew are studied.The pathogen caused primery infection and rapid spread at the end of March in 2008.The infection becomes slowly in hot summer,and reach epidemic stage again in autumn.Leaves of tender branch and close planting are infected seriously.Light deficiency and moist can worsen the condition. Temperature and humidity greatest effect conidia germination, The suitable temperature for germination is 16 to 23℃,the suitable humidity is 25%～100%,the suitable pH is neutral condition,and seventeen hours is the germination peak period.Twelve fungicides were used in the tests on chemical control of the powdery mildew of Plantnas and Folium mahoniae.The result shows that the effect of inhibiting spore germination of diniconazole,flusilazole,azoxystrobin and fenshi was comparatively well. Besides tuzet to the powdery mildew of Folium mahoniae have a good effect.Based on the experiments of the powdery mildew of Folium mahoniae in fields,the control effect of flusilazole and azoxystrobin was comparatively well. Secondly it is tuzet, diniconazole was relatively poor.