不同杀菌剂对番石榴枝枯病病原菌的毒力和田间防效

为有效防治我国近些年新发现的番石榴枝枯病,本研究采用菌丝生长速率法和孢子萌发法,测定了8种杀菌剂对番石榴枝枯病菌(小新壳梭孢)的毒力,筛选出高效药剂,并进行田间防治试验。结果表明:30%咪鲜胺CS对小新壳梭孢的抑菌能力最强,EC_(50)为0.2 mg/L;其次是60%苯醚甲环唑WG和35%苯甲·嘧菌酯SC,EC_(50)分别为0.23和0.29 mg/L。30%咪鲜胺CS和35%苯甲·嘧菌酯SC对小新壳梭孢分生孢子萌发的抑制作用最强,EC_(50)分别为0.07和0.09 mg/L;30%咪鲜胺CS和60%苯醚甲环唑WG的预防作用和治疗作用效果也最好;田间试验结果表明,使用30%咪鲜胺CS和60%苯醚甲环唑WG防治番石榴枝枯病的防效最好,达到56.87%和52.40%,有较大的应用潜力。

Virulence and control efficacy in field of different fungicides against the pathogen of guava shoot blight

Guava shoot blight of is a new serious disease which infects guava twigs in the southern China in recent years. The objective of this study was to screen the effective fungicides against the disease. The virulence of eight fungicides against the pathogen Neofusicoccum parvum was tested in the laboratory by the methods of mycelial growth and spore conidial germination, and the fungicides with high virulence were used in the field control trials. Results showed that prochloraz 30% CS exhibited the strongest inhibitory activity with EC50 value of 0.2 mg/L, followed by difenoconazole 60% WG and difenoconazole·azoxystrobin 35% SC, with EC50 values of 0.23 mg/L and 0.29 mg/L, respectively. Meanwhile, prochloraz 30% CS and difenoconazole·azoxystrobin 35% SC had maximum toxicity against spore germination with the average EC50 values of 0.07 and 0.09 mg/L, respectively. Moreover, prochloraz 30% CS and difenoconazole 60% WG showed high preventive and curative activity against N. parvum. Field experiment showed that prochloraz 30% CS and difenoconazole 60% WG had great potential to control guava shoot blight, with the control efficacies of 56.87% and 52.40%, respectively.