Walnut Branches Blight Pathogen Identification And Pharmacy Prevention Research

Walnut branches blight is invaded and infected by the fungus, resulting in walnut branches wilt, rot, broken, a serious disease, the media mainly are the air,the rain and the insects, the birds, the animals,and so on. Although the experts and the scholars had launched extensive research on the walnut branches blight, however, because of the complexity of the geographical terrain, climate soil environment, disease pathogens and other characteristics, causing walnut branches blight pathogen, there are some gaps.In this paper.some major cultivation areaYa’an, Mianyang, Yibin in Sichuan walnut had conducted invested and researched branches blight, analyzing its growth environment conditions and determining occurrence and prevalence of symptoms.With the ultimate goal of prevention, we mainly invested the branches of walnut blight infection in Sichuan, pathogen species identification, biological characteristics of the pathogen, the dynamic field of disease prevention and control of indoor and outdoor observation research,we had achieved the following results:(1) We continued to observed the main cultivated field walnut onset dynamic during the 2014-2015, the results showed that the incidence of early blight walnut branches spread around by small spots of infection, the formation of massive, oval or irregularly shaped wounds color from the initial site of dark green or light green becoming gray and black, and then all black.The disease became ill and rapid expansion of the disease from March to April in the warmer spring, to the peak of summer, especially in August reached a climax, strain rate of 35%.During the September-October the disease gradually became weakened and the disease was at a standstill in December-February;also we combined annual determination of early onset in March, the peak period in July and August.(2) By the law of Koch assumed and according to the experimental method tieback isolated and purified,the strain was inoculated about 7days, the rapid expansion of the lesion from the small-scale and almost it caused a branches blight symptoms of diseased plants which were isolated and cultured according to routine, we got found pathogen characteristics and features of the original pathogen inoculation basically the same, namely to confirm BH01-BH05 walnut branches blight which were caused by bacteria.(3) Through the strain BH01-BH05 colony hyphae, spores form, color change morphology,we found the growing, the color, the shape and the size characteristics were basically the same, so we made sure BH01-BH05 for the same species, refer to the relevant literature and combine molecular biology test sequence to establish the phylogenetic tree, identified as a new strain BH01 shuttle shell spore (Neofusicoccum parvum).The bacteria wre generally covered the entire diameter of about 7days PDA 9cm culture plates, forming a circular or nearly circular colonies after UV irradiation in about 10min and then it cultured 7d after sporing capacity rapidly,near into a nearly circular or not regular shape, the size in (15.2～17.2)μm×(4.6～6.4)μm.In the rDNA-ITS sequence amplification and sequencing, we used the software clustalX and Mega 5.0 software for analyzing and comparing to establish the phylogenetic tree and we found the bacteria in a parallel tree Neofusicoccum parvum (GenBank accession number:FJ904915) homology the highest, reaching 99%. Swedish foreign bacteria in Peru had caused grapes, walnuts and other branches blight, but the cause of the walnut branches blight was first reported series.(4) Measured by walnut branches blight pathogen biological characteristics,walnut branches blight could spread popular rapidly and there was an adaptation of the environment compared with ecological conditions.and it was found that the bacteria spores shed new shell (Neofusicoccum parvum) can grow in different culture medium, but it grow best PDA medium, followed by PSA medium, Czapek medium was relatively good.The bacteria growth temperature for 25-35℃, which was the optimum temperature 25℃. PH range could grow at all, but the optimum growth of pH8. A light, and a high relative humidity under conditions conducive to teach bacteria fastest.The best carbon source is glucose,the most times is mannitol.One of the best nitrogen source for glutamic acid, and urea significantly inhibited colony to grow slowly; by measuring to determine the lethal temperature is 60℃.By late summer we can determine which based on the results of environmental Sichuan Basin environment, high temperature, greater humidity,Biological characteristics and experimental determination of the most appropriated environment similar disease,it also occurred in severe cases, and therefore the disease incidence and prevalence of intermittent predictability, for the first peak of the focus on disease prevention and control work provides an important theoretical basis(5)In the process of communication and wintering pathogens,we found walnut branches blight mainly through rain, wind, air, insects and other communication, including decaying litter in the second year which would be more likely to cause disease, so it was the usual attention good waterproof plastic trim and walnut work, good autumn and winter field Grottoes litter cleanup and promptly eliminate the diseased leaves on the plant stems and advance chemical control, may be appropriate to reduce the source of disseminated disease. The bacteria grow weak in the winter, the low incidence or not the disease, but in the case would be the onset of warmer spring temperatures.(6) Pharmacy screening results were displayed in the room, nine kinds of agents in concentrations 1.25ug/mL-40ug/mL in the interval,9 kinds of agents in the concentration range 1.25ug/mL-40ug/ mL,with the increasing of medicine concentrated the colonies which began to become smaller,the trials in which the walnut branches blight pathogen mycelium inhibition resulted indicate that the determination of the effective concentration, thiophanate-methyl, carbendazim and chlorothalonil had significantly inhibited on walnut branches blight bacteria, thiophanate methyl EC50 values for the smallest pathogens walnuts for 4.5214ug/mL, showed Pharmacy inhibition of the best, followed by carbendazim and chlorothalonil, and the EC50 values were 4.6240 ug/mL,7.1930 ug/mL.In practical prevention pot we found in the same concentrations, the best prevention was thiophanate-methyl, followed by carbendazim and chlorothalonil, and indoor chemical screening were the same, among the best control effect concentration field than Fungicide optimal control effect concentration filtering,multiplexing and other reasons, such as climate and geographic location. Therefore, it should be based on the best control effect on the interior, in the wild to increase medicine concentration control.