Studies On The Pathogeny Biology Resistant Cultivar And Fungicides Screening Of Asparagus Stem Blight In Hainan

Asparagus (Asparagus officinalis L.), is very popular to the consumers because it is delicious and rich in nutrition. Known as the king of the vegetable.In china, asparagus stem blight is a devastating disease in asparagus production areas,especially in south China.So that,it threated the healthy development of asparagus industry.In this article, we survey this disease,isolate and identify the pathpogen,in the same time, from the aspects of etiology,chemical control and varieties of resistance to carry on the research,and achieved the following findings to provide a scientific basis on breeding resistant varieties and treatment measure in production.1.Investigate the Asparagus stem blight in four main Asparagus production of Hainan province,separate and purificate the pathogen,obtained eight bacterial strains in all.2. Analysis the rDNA ITS sequences of four typical bacterial strains. The results showed that:the length of ITS of all4tested bacterial strains was about600bp. The comparating analysis of blast in gene-bank showed that this four bacterial strains were all Phomopsis asparagi sacc. From the phylogenetic tree,the homology of this four bacterial strains is very high.3.The biological characteristics experiments showed that the growing rate of pathogenic bacteria in the PSA medium is the fastest and the colony is density.the colour is white,the spores amount are the most; The optimum temperature for the hyphae growing is25degrees; The optimal PH is5.0,The lethal temperature of hyphae is60degrees,10minutes.4.The screening experiment of disease-resistant varieties indicate that the high resistant varieties are wild type DaliasparagusandB7/TX-4,The moderately resistant varietiesare jinggang701,TCshandong jinggangmycinall-male(2),B4-a/B20-a(purple), B19-c(H),B2-a/SD,B3/TX-6,The highly susceptible varieties are champion,jinggang mycin red, B23(05)-â‘ /B2(H).5.The indoor toxicities of15kinds fungicides was determinated.The result is:the minimalEC50values is carbendazim,0.8721mg/L, followed by theThiophanate,chlorot-halonil,Azoxystrobin,Armure,Iprodione, Mancozeb is1.4404,1.6557,3.2345,6.4986,6.7205,15.5960mg/L.Using the five fungicide which is better in toxicity determination to the field experiment,The comprehensive anti efficient respectively is77.88%,58.63%,55.70%.So in production this5insecticides can used in field trials and notice the rotated using to avoid the fungicide resistance.