青花菜根肿病田间防治技术研究

Study on technology of controlling Plasmodiophora brassicae on broccoli in field

2018年开展青花菜根肿病田间防治试验,移栽后用5种药剂灌根处理。分别进行了5种药剂灌根次数试验、3种药剂灌根剂量试验和3种药剂灌根时期试验。试验结果表明,5种药剂中500 g/L氟啶胺SC是防治青花菜根肿病的最佳药剂,但使用不当会有药害风险,移栽当天用2250 g/hm^2、移栽后3 d用3375 g/hm^2和4500 g/hm^2灌根,花球成熟期推迟,株高、最大叶面积均不同程度受抑制,尤其在苗期使用会明显抑制生长,表现为植株矮小、叶片黄化、无法正常盘根。建议用2250 g/hm^2分别在移栽后3~7 d和移栽后30 d各灌根1次。其次采用100 g/L氰霜唑SC,338 g/hm^2在移栽后0~3 d和30 d灌根也可取得较好防效。75%百菌清WP 8440 g/hm^2与100 g/L氰霜唑SC 338 g/hm^2防效相当。20%噻唑锌SC防效较低,62.5 g/L精甲·咯菌腈FSC防效最差,不适宜用在根肿病防治上。

Field control effects of five fungicides against the crucifer clubroot on broccoli were investigated by root drenching after transplanting in 2018.The times,doses and application time of root drenching on control effect against clubroot were evaluated.The results showed that fluazinam 500 g/L SC was the best one among the five fungicides.However,improper use might lead to phytotoxicity.The plant height and the maximum leaf area were inhibited to some extent by root drenching with fluazinam 500 g/L SC 2250 g/hm^2 on transplanting day or,3375 g/hm^2 and 4500 g/hm^23 days after transplantation.Especially,at the seedling stage,the plant growth were obviously inhibited,the plants became short,the leaves turned yellow,and the root system failed to pack properly.Therefore,it was suggested that fluazinam 500 g/L SC at the dose of 2250 g/hm^2 should be used to irrigate roots on 3th-7th day and 30th day transplanting to achieve good control effect.Cyazofamid 100 g/L SC at 338 g/hm^2 also showed good control effect when used it on transplanting day and 30 days after transplanting.The control effect of chlorothalonil 75%WP at 8440 g/hm^2 was similar with that of cyazofamid 100 g/L SC at 338 g/hm^2.However,the control effects of zinc thiazole 20%SC and metalaxyl-M·fludioxonil 62.5 g/L FSC were poor,indicating they were not suitable for clubroot control on broccoli.