Erwinia amylovora causes fire blight, a bacterial disease of pome fruits. For 15 years, fire blight management in Israel was based solely on the antibiotic oxolinic acid but, in response to decreased disease-control efficacy, copper agents were added in 2014. However, concern was raised as to whether repeated applications of copper might have impaired pollen germination and thereby impaired yields. In Israel, apple cultivars, except for the early-blooming cultivar ‘Cripps pink’ (trademark Pink Lady), appeared to be markedly less sensitive to the infection than pear cultivars (‘Spadona’ and ‘Costia’). The aims of the present study were to monitor the effects of treatments with copper-based agents during blossoming in reducing fire blight damage, while recording their effects on pollen-tube germination and fruit-yield parameters. Copper tribasic sulfate and copper hydroxide reduced disease levels by more than 70% compared with uninfected controls. Pollen-tube germination rates in both apples and pears were significantly reduced after two successive daily applications of copper tribasic sulfate, but usually they recovered to control levels after introduction of a single-day interval. Four to seven seasonal applications of copper agents on apple and pear blossoms did not significantly reduce fruit weight and size, seed number, seed-set or fruit-set. The efficacy of oxolinic acid, applied either alone or tank-mixed with copper, resembled that of copper alone. In summary, copper application against fire blight in pears and apples during their blooming in Israel is both effective and harmless to yields.

中文翻译：

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以色列北部梨果火疫病防治效果：铜剂及其对产量参数的影响

Erwinia amylovora 导致火疫病，一种梨果的细菌病害。15 年来，以色列的火疫病管理完全基于抗生素恶唑酸，但为了应对疾病控制效果下降的问题，2014 年添加了铜制剂。 然而，人们担心重复使用铜是否会损害花粉发芽，从而降低产量。在以色列，除早花品种“Cripps pink”（商标 Pink Lady）外，苹果品种对感染的敏感性似乎明显低于梨品种（“Spadona”和“Costia”）。本研究的目的是监测开花期间铜基药剂处理对减少火疫病危害的效果，同时记录它们对花粉管萌发和果实产量参数的影响。与未感染的对照相比，硫酸三铜和氢氧化铜使疾病水平降低了 70% 以上。连续每天施用两次硫酸三铜后，苹果和梨的花粉管发芽率均显着降低，但通常在引入单日间隔后恢复到控制水平。在苹果和梨花上季节性施用 4 到 7 次铜剂并没有显着降低果实的重量和大小、种子数量、结实率或坐果率。单独使用或与铜混合使用的恶唑酸的功效与单独使用铜的功效相似。总之，在以色列梨和苹果开花期间施用铜来防治火疫病既有效又对产量无害。