四种杀菌剂防治猕猴桃溃疡病的效果及田间应用技术

为探究猕猴桃溃疡病的化学防治技术,采用离体枝条室内生测及田间试验的方法,对72%农用链霉素SPX、46%氢氧化铜WG、20%叶枯唑WP及1.5%噻霉酮EW的预防和治疗效果以及施药的时期和方法进行了研究。结果显示,供试杀菌剂对猕猴桃溃疡病均有显著的预防效果和一定的治疗效果,在浓度为4.0 mg/m L和2.0 mg/m L时,对病害病斑15 d的预防效果分别达到100%和68.0%以上,较相同浓度的治疗效果高2~3倍,预防和治疗效果均达到90%时的杀菌剂浓度分别为3.07~3.35 mg/m L和8.32~10.81 mg/m L,药效持效期约为11~14 d。田间全树喷雾和树干涂药试验表明,农用链霉素和氢氧化铜预防效果较好,超过60%;秋冬季枝干发病前施药4~5次预防效果可达70%左右;枝干发病显症初期采用病斑划道后涂药治疗效果较好,但对大于15 cm的中大型病斑治疗效果较差,而枝干发病后采取药剂注射及药剂涂抹法治疗病斑效果均较差。表明秋冬季是预防猕猴桃溃疡病的关键期,而发病初期为治疗最佳时期。

Bactericidal activities of four bactericides and their field application against Pseudomonas syringae pv. actinidiae

In order to develop chemical methods for effectively controlling bacterial canker of kiwifruit, four commercial bactericides, namely 72% streptomycin SPX, 41% copper hydroxide WG, 20% bismerthiazol WP and 1.5% benziothiazolinone EW, were evaluated by both indoor and field performances. In the trials, control efficacies on excised canes and living trees in orchards, and their application patterns and timing were both investigated. All four bactericides showed significantly good preventative efficacy and certain therapeutic efficacy. In indoor assays, the preventative efficacy of all tested bactericides at the dose of 4.0 mg/mL and 2.0 mg/mL were 100% and more than 68%, respectively, showing 2-3 times higher therapeutic efficacy. The doses for 90% preventative and therapeutic efficacies were 3.07-3.35 mg/mL and 8.32-10.81 mg/mL, respectively, and the durations for both preventative and therapeutic efficacy were 11-14 days. In field trials, the results of entire-tree spraying or an alternative trunk smearing showed that the efficacies of streptomycin and copper hydroxide were over 60%, significantly higher than those of bismerthiazol and benziothiazolinone. In application timing assays, when applied in autumn and winter prior to disease development, the preventive efficacy was approximately 70% with a total of four to five treatments. In early stage after disease appearance, bactericide smearing on the scratching lesions offered a relative good therapeutic effect to the new lesions, but poor effect to the large-size lesions (>15 cm). However, once disease developed, both bactericide injection and bactericide smearing on lesions showed poor effects. Taken together, autumn to winter prior to disease development is the critical period for disease prevention, and early stage after disease appearance is the best time for disease therapy.