Analysis Of Monitoring And Control Of Hevea Brasiliensis Anthracnose In Hainan Province

Rubber tree(Hevea brasiliensis)is the only renewable resource among the four major industrial raw materials.The rubber tree anthracnose which infected by the Colletotrichum spp.is one of the most serious foliar disease of rubber production in China.In this paper,through the joint investigation and monitoring of the epidemic situation of rubber tree anthracnose in Hainan Province,36 rubber tree varieties(strains)were evaluated for their resistance to anthracnose and the following operations were also implemented:samples were collected,pathogens were isolated,and a new strains of Colletotrichum karstii was identified and analyzed for carbendazim(2-benzo imidazole methyl carbamate)and prochloraz-manganese chloride complex resistance,meanwhile the control technology of unmanned aerial vehicle(UAV)for rubber nurseries anthracnose was tested.Through the above research the main results were obtained as follows:In cooperation with Hainan Natural Rubber Industry Group Limited Liability Company,the anthracnose epidemic situation of PR107,RRIM600 and Reyan 7-33-97 were investigated and monitored.It was found that the planting areas of PR107 and RRIM600 were 102,000 hm2(51.06%)and 86,700 hm2(43.39%)respectively.The anthracnose of mature rubber plantations and value-added nurseries in Qiongzhong Yangjiang Farm was occurred all year round,with the peak period from March to April.The evaluation of anthracnose resistance of 36 rubber tree varieties(strains)inoculated with representative strains HCgGX1649 and HCaYNJP162 showed that 6 varieties(strains)of GT1,PB86,Reyan 7-20-59,Wenchang 193,Wenchang 7-35-11 and Zhenxuan 1 had moderate resistance(MR),while 24 varieties(strains)of Wenchang 11,Reyan 7-33-97 and Yunyan 77-2 et al.were susceptible(S),and the last 6 varieties(strains)of PR107,RRIM600 and Dafeng 99 et al.for the middle sensation(MS).From 2017 to 2018,264 anthracnose samples were collected from the main rubber planting areas in Hainan Province,and 140 anthracnose isolates were obtained.Among them,HCkHNQZ1736 which isolated from the leaves of the rubber nursery of Yangjiang Farm in Qiongzhong County,the pathogen was identified as a new strain of Colletotrichum karstii,the pathogen had highly pathogenic to four main varieties,PR 107,RRIM600,Reyan 7-33-97 and Dafeng 95.Combining morphological observation and polygenic phylogenetic analysis,this study found that the optimum temerature for 28?,and the lethal temperature of 35?.The optimum pH for 6;the study also found that the alternation of light and dark was beneficial to colony growth,and the pectin and peptone were the optimum carbon and nitrogen sources respectively.Studied on the results of carbendazim and prochloraz-manganese chloride complex sensitivity test of HCkHNQZ1736 and MeCkYN1705 showed that the two strains had no resistance to prochloraz-manganese chloride complex,a sterol demethylation inhibitor(DMIs)fungicide,while the EC50 was 0.0784 ?g/mL and 0.0775 ?g/mL respectively.However,HCkHNQZ1736 showed high resistance to benzimidazole fungicides carbendazim,at this time,the EC50 was 1107.265?g/mL,while MeCkYN1705 had only 0.055 ?g/mL.After the HCkHNQZ1736 tub2 gene was cloned,sequence analysis showed that the 198th amino acid locus was mutated from glutamic acid(Glu-E)to alanine(Ala-A).This paper speculated that the mutation of the amino acid locus was the cause of carbendazim resistance of the strain.In this paper,the results of UAV control test of a new type of agent "Baoyeqing"microemulsion for the control of anthracnose in rubber trees showed that:Test.l,when the UAV flew 2 metres higher than the crown and no flight control aids "Refei" were added;the corrected control effects were 46.33%and 55.91%with 3%and 4%"Baoyeqing"microemulsions were applied respectively;Test.2,under the condition of the UAV flew 1 metre higher than the crown,1%"Refei" were added,and 3%and 4%concentration of"Baoyeqing" microemulsions for correction,the control effect was 67.42%and 73.27%respectively;Test.3,when the UAV flew 2 meter higher than the crown with 1%"Refei",the control effect was 71.27%and 80.07%respectively when 3%and 4%"Baoyeqing"microemulsion were applied respectively.The results showed that the dosage was safe for rubber trees and environment.