Identification And Fungicides Screening Of The Copper Blight Pathogen Of Cunninghamia Lanceolata In Fujian

Chinese fir(Cunninghamia lanceolataolata)is one of the most important commercial tree species in southern China,which has a long history of cultivation.It is cultivated in large numbers for its fast growth,high yield,good quality and multiple functions.The pathogen of copper blight of Chinese fir invade from the needles,then the needles graduate copper brown,and extend to the tops,finally the tops dead or the plant even dead.In recent years,the copper blight has become one of the most important diseases in the seedling stage of Chinese fir.At present,there are a variety of reports about the pathogen of copper blight;and the fungicides for control copper blight in accordance with the use of fungicide which for control fungal disease of agricultural crops.The lack of screening for copper blight lead to use fungicide irrationally.In view of this,we have carried out the identification of the pathogen of copper blight of Chinese fir in some areas of Fujian Province,and screenthe fungicides for control the pathogen.We determined the species of pathogen and the sensitivity of Chinese fir copper blight to fungicides.The results provide scientific support for the scientific and rational use of fungicides.It can reduce the fungicide dosage,save the cost,increase the economic benefit and protect the ecological environment.The main results are as follows:1.In this paper,samples of copper blight were collected for isolating pathogens from Zhangzhou Nanjing,Nanping,Longyan Changting,Ningde,Mount Wuyi.All the isolations were identified through the combination of morphological and molecular identification.The 46 of isolations were identified as Pestalotiopsis sp.the other were identified as Xylaria,Nigrospora,Colletotrichum and so on.Among the 46 strains,11 strains belong to Pestalotiopsis microspora of,24 strains are Pestalotiopsis theae,and Pestalotiopsis oxyanthi contain 7 strains,and 4 strains are Pestalotiopsis cocculi.2.The pathogenicity of different species from different regions was determined by pin-prick inoculation and non pin-prick inoculation.All of the strains adopting pin-prick inoculation had symptoms.But the symptoms of Pestalotiopsis oxyanthi and Pestalotiopsis cocculi were not obvious.The results showed that there was no significant relationship between the pathogenicity and the source area in Fujian Province.The pathogenicity of Pestalotiopsis microspora and Pestalotiopsis theae was stronger.In the way of non pin-prick inoculation,none of them had symptoms of disease,indicating that Pestalotiopsis sp.was difficult to infect the plant with the absence of wound.The pathogenicity test confirmed that the Pestalotiopsis sp.could induce the fungus the copper blight of Chinese fir.3.Carbendazim,Difenoconazole and Iprodione were used to determine the toxicity of Pestalotiopsis sp.The toxicity test of P.microspora in different regions showed that Carbendazim had the most stable effect on restraining the fungus hyphae growing.The highest level of EC50 was 0.18 ?g·mL-1 from the Zhangzhou Nanjing.The lowest level of EC50 was 0.1 ?g·mL-1 from the Mount Wuyi.The toxicity test of 4 species of Pestalotiopsis sp.from diverse regions show that Carbendazim had the best effect on restraining the fungus hyphae growing,and the average value of EC50 is 0.19?g·mL-1.The second is Difenoconazole,and the average value of EC50 is 10.42?g·mL-1.The least effective is Iprodione,and the average value of EC50 is 21 ?g·mL-1.In summary,the main pathogens causing copper blight of Chinese fir in Fujian Province were Pestalotiopsis.In the three kinds of Fungicide,the suppression effect of Carbendazim is the best and most stable.It is recommended to use Carbendazim against copper blight of Chinese fir in the region.