Identification And Biological Characteristics Of Three Important Diseases On Jackfruit And Screening Of Fungicides In Hainan

Jackfruit (Artocarpus heterophyllus Lam) is one of evergreen fruit-trees. As one of the most south provinces,Hainan Province also is the most productive area. In recent years, by the need of market and the encouragement of the government, Large-scale cultivation were continuous increasing in Hainan province.cultivated area is more than40000mu by far. About20fungi diseases disappeared,which caused serious economic loss in Jackfruit industries of Hainan Province. Most of the diseases have no systematic study. In this dissertation, Root rot of Jackfruit, Stem-end rot of Jackfruit, and Rhizopus Rot of Jackfruit were indentified and biological characteristic, the fungicides screening in laboratory. All results were reported as followed:1. The investigation show that Rhizopus Rot of Jackfruit mainly happens on the flower and young fruit, almost all of the Jackfruit trees are nonresistant in every plantation,incidence of Male flowers can be reached90%. Stem-end rot of Jackfruit(SER) is also general in the plantation, Young fruit and mature fruit all can be infected,incidence of Stem-end rot was about20%. Root rot of Jackfruit can be found in every plantation, a number of plants have this serious disease. The prevalence rate of Root rot can be reach40%.2. Rhizopus Rot of Jackfruit?the Pathogen was identified according to morphological Characteristics and ribosomal DNA internal transcribed spacer(rDNA-ITS) sequence analysis,biological characteristics were useing colnoy growth and slide methods. The objective sequence was856bp. Among them, The results showed that the representative isolates was identified Rhizopus stolonifer (ehrenb.ex fr.) Vuill.3. Stem-end rot of Jackfruit:according to Koch's law,the Pathogen was identified according to morphological Characteristics ITS,GAPDH,ACT,CHS-1and TubG2sequence analysis, the objective sequence were533bp,248bp,255bp,274bp and492bp.The results showed Stem-end Rot of Artocarpus heteophyllus Lam is caused by Colletotrichum siamense. This is the first report demonstrating that Colletotrichum siamense can lead to SER in jackfruit4. Root rot of Jackfruit:the Pathogen was identified according to morphological Characteristics and ribosomal DNA internal transcribed spacer(rDNA-ITS) sequence analysis,biological characteristics were useing colnoy growth and slide methods,the objective sequence was549bp.Among them, The results showed that the representative isolates was identified Fusarium solani.This is the first report demonstrating that Colletotrichum siamense can lead to root rot in jackfruit.5. The study on biological characteristics of Rhizopus stolonifer (Ehrenb.ex Fr)Vuill shows that the mycelium grew faster which on the Jackfruit pulp-squeezing medium. The most suitable temperature was28?and pH6-7was the most suitable for mycelia growth. The suitable nitrogen source was peptone.The lethal temperature of mycelia was59?for10min in water bath.The study on biological characteristics of Colletotrichum siamense shows that mycelium grew faster which on the PDA medium and Czapek culture medium; The most suitable temperature was28?and pH7was the most suitable for mycelia growth. The lethal temperature of mycelia was58?for10min in water bath. L-Arabinose, dextrose, maltose and fructopyranose all can be the suitable carbon source;nitrogen source was peptone.The study on biological characteristics of Fusarium solani shows that effects of different cultures on mycelial growth were significant,optimal culture for mycelial growth was young-fruit decocted with liquid of jackfruit; Effects of temperatuer, pH,carbon and nitrogen sources on mycelial growth and spore germination had significant differences, optimal temperature for mycelial growth was28?,fatal temperature for mycelial growth was63?,10minutes;optimal temperature for spore germination was25?;pH7was the optimal pH for mycelial growth;the optimal carbon source for mycelial growth was dextrose, Ammonium nitrate was the optimal nitrogen sources for mycelial growth.6. The toxicities of thirteen fungicides have different degrees inhibition on Rhizopus stolonifer (Ehrenb.ex Fr)Vuill. Difenoconazole10%WP had the strongest of toxcity with EC50values of8.9815?g/mL on the growth of Rhizopus stolonifer.7. The toxicities of thirteen fungicides have different degrees inhibition on Colletotrichum siamense. prochloraz-manganese chloride complex50%WP had the inhibitory effect on Colletotrichum siamense with EC50values of0.0602?g/mL on mycelial growth of Colletotrichum siamense.8. The toxicities of thirteen fungicides have different degrees inhibition on Fusarium solani. Chlorothalonil40%GP had the strongest inhibitory effect on Fusarium solani with EC50values of0.0024?g/mL on mycelial growth of Fusarium solani.