甜瓜茎基腐病病原菌鉴定及其植物源杀菌剂室内毒力测定

Identification of Pathogens Causing Muskmelon Stem Basal Rot and Screening of Botanical Fungicides

为明确2023年齐齐哈尔市农业技术推广中心甜瓜栽培基地的甜瓜幼苗茎基腐病的发病原因,筛选出对其具有高毒力的植物源杀菌剂,采用组织分离法对发病茎基部的甜瓜幼苗进行病原菌的分离。得到两株病原真菌,经形态学及ITS-rDNA分子鉴定,分别为Fusarium oxysporum和Fusarium nirenbergiae。致病性试验表明两株镰孢菌都能够侵染甜瓜幼苗茎部,导致茎基腐病的发生。5种植物源杀菌剂对两株病原真菌的菌丝生长抑制和毒力测定试验结果表明,20%丁子香酚、0.5%苦参碱和2.1%丁子·香芹酚的所有有效浓度对两种致病菌的菌丝生长抑制率均能达到30%以上。20%丁子香酚、0.5%苦参碱、0.5%小檗碱、2.1%丁子·香芹酚、80%乙蒜素对F.oxysporum的EC 50值分别为9.413,21.497,36.670,48.342和48.575 mg·L^(-1);对F.nirenbergiae的EC 50值分别为13.768,14.697,43.260,32.475和34.158 mg·L^(-1)。综合分析表明,5种植物源杀菌剂中,20%丁子香酚对甜瓜茎基腐病致病菌的毒力最强。

In 2023,stem basal rot disease of muskmelon seedlings was found in the muskmelon cultivation base of Qiqihar Agricultural Technology Extension Center.In order to identify the cause of the disease and screen out effective botanical fungicides with high virulence against pathogens,tissue separation method was used to isolate the pathogens from infected stem.Two pathogenic fungi were and purified from diseased seedlings,and were identified as Fusarium oxysporum and Fusarium nirenbergiae by morphological characteristic and ITS-rDNA sequences.Pathogenicity experiments showed that both strains can infect melon seedlings,leading to the occurrence of stem rot disease.Five plant botanical fungicides were accessed the inhibition on the mycelial growth and the toxicity to two fungi.The results showed that all effective concentrations of 20%eugenol,0.5%matrine and 2.1%carvacrol can inhibit the hyphae growth of two pathogens by more than 30%.The EC 50 values of 20%eugenol,0.5%matrine,0.5%berberine,2.1%eugenol,and 80%allicin for F.oxysporum were 9.413,21.497,36.670,48.342 and 48.575 mg·L^(-1),respectively.The EC 50 values for F.nirenbergiae were 13.768,14.697,43.260,32.475 and 34.158 mg·L^(-1),respectively.It indicates that among the five botanical fungicides,20%eugenol has the strongest virulence against the pathogens of musk melon stem basal rot disease.