| Moringa oleifera is native to India and Africa, belonging to the suborder Moingineae,Moringaceae, M. oleifera Adans, Perennial evergreen tree or perennial tropical deciduous tree. M. oleifera is a very useful tree, since it is rich in nutrients and can be used as a medicinal plant and for water purification. It is now widely distributed in more than and 30 tropical and subtropical countries in Africa, Asia and central america. In recent years, the cultivated area in China continues to expand, however due to cultivation of backward technology, extensive management and the climate impact, Moringa cultivation process by pest threat. It has been reported that the disease is mainly Fusarium semitectum ,Fusicladium pallidorseum infecting fruit pod and stem. In November 2015,approximately 20 hectares of several M. oleifera fields in the Hainan province were severely defoliated, Corynespora cassiicola causing target spot and Fusarium equiseti causing shoot blight on M. oleifera .This is the first report of F. equiseti causing shoot blight and C. cassiicola causing target spot on M. oleifera in China.This test of the two kinds of disease used of Koch's postulation, Morphological characteristics observation rDNA -ITS sequence analysis and other methods to identify the disease caused by pathogen and determination of biological characteristics, indoor fungicides screening, and green fluorescent protein (GFP) labeled C. cassiicola to intended for the early diagnosis of the disease, and providing a theoretical basis for prediction and control in field. The main research results:1. Identified two new diseases clearly :The F. equiseti causing shoot blight on M.oleifera, and the C. cassiicola causing target spot in M. oleifera.2. Biological characteristics: For mycelial growth of F.equiseti,the suitable temperature ranged from 25 ? to 30? and the optimum temperature was 28?.For mycelial growth, the suitable pH value ranged from 6 to 8, and the optimum pH value was 7. Under the condition of different culture medium,the optimum medium was PDA and PSA due to the mycelial growth fastest and densely. Different light conditions has a little influence on the mycelium growth, there was no significant difference.when Sucrose as carbon source and beef extract as nitrogen source utilization rate is highest and mycelial grow the fastest.The fatal temperature for mycelial growth was 65 ? for 10 min. For mycelial growth of C.cassiicola the suitable pH value ranged from 6 to 8, and the optimum pH value was 7. Under the condition of different culture medium,the optimum medium was PDA and PSA due to the mycelial growth fastest and densely. when Sucrose and xylose as carbon source and beef extract and tiyptone as nitrogen source utilization rate is highest and mycelial grow the fastes. Different light conditions has a little influence on the mycelium growth, there was no significant difference. the suitable temperature ranged from 25? to 30? and the optimum temperature was 28?.The fatal temperature for mycelial growth was 60? for 10 min.3. GFP mark C.cassiicola target spot of M. oleifera:Transformants,in stable issued a green fluorescence in hyphae, conidia, was gained by PEG-mediated method. There were no difference between the transformants and wild in shape, color and pathogenicity, but transformants is slower than the wild strain in growth rate. Pathogenicity was not reduced compared with wild strain.4. Screening of fungicide: The F. equiseti shoot blight on M. oleifera, Toxicity test of 10 kinds of fungicides showed that Propiconazole have better inhibitory effect, EC50 value was 0.167?g/mL, EC90 was 3.951 ?g/mL. The next were Flusilazole, Prochloraz,Tebuconazole, Myclobutanil, Difenoconazole, EC50 values were 0.39, 1.409, 1.411, 7.271,8.561 ?g/mL. Mancozeb, Thiophonate-methyl, Chlorothalonil EC50 values were 18.921?32.594?76.764 ?g/mL inhibitory effect was relatively poor. Iprodione EC50 value was 90.59 ?g/mL virulence weakest. C. cassiicola target spot of M. oleifera, Toxicity test of fungicides showed that Flusilazole EC50 value was 0.184 ?g/mL, EC90 value was 160.4?g/mL, Thiophonate-methyl EC50 value was 3.335 ?g/mL, EC90 value was 50.808?g/mL,Comprehensive consideration, Thiophonate-methyl is highest toxicity, The second is Fluorosilicone. Prochloraz, Propiconazole, Tebuconazole,Mancozeb EC50 values were 6.382?8.154?13.649?26.716 ?g/mL. Difenoconazole, Iprodione, Myclobutanil EC50 values were 0.852?31.13?36.181 ?g/mL inhibitory effect was relatively poor. Chlorothalonil EC50 value was 269.497 ?g/mL virulence weakest. |
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