乙氧氟草醚对脐橙的杀梢效果及对柑橘木虱栖息分布的影响

Shoot-killing effect of oxyfluorfen on navel orange and its effect on the habitat distribution of citrus psyllid,Diaphorina citri Kuwayama

柑橘木虱偏好产卵于柑橘嫩梢新芽上,在统一抹芽放梢后及时施药防治木虱,成为防控柑橘黄龙病的重要措施。近年通过杀梢剂处理杀灭新发嫩梢代替人工抹梢受到果农的关注和使用,并已成为防治黄龙病的重要技术手段。本研究以纽荷尔脐橙为供试树种,喷施不同质量浓度的乙氧氟草醚药液,探究其杀梢效果及对柑橘木虱栖息分布的影响,并建立了嫩梢萎蔫的分级标准和木虱栖息分布的研究方法。结果表明:乙氧氟草醚对脐橙树苗和定植树有相似的杀梢效果,质量浓度为10 mg/L时即有一定的杀梢作用,40~55 mg/L时杀梢效果最佳,速效性优异,对柑橘叶片和成熟期果实无药害。采用40和55 mg/L的乙氧氟草醚药液对树苗喷雾,3 d后,嫩梢长度抑制率分别为86.1%和124.7%,嫩梢直径抑制率分别为83.8%和94.8%;7 d后,校正杀梢率分别为93.7%和84.1%,木虱校正死亡率分别为7.8%和21.4%,木虱栖息抑制率分别为81.0%和84.4%。采用40、55 mg/L的乙氧氟草醚药液对定植树喷雾,3 d后嫩梢长度抑制率分别为85.9%和118.8%,嫩梢直径抑制率分别为83.9%和104.1%;7 d后校正杀梢率分别为96.6%和82.4%。嫩梢萎蔫可使嫩梢上的木虱虫卵和若虫死亡,对成虫死亡率影响小,但栖息环境发生迁移。因此,乙氧氟草醚施用于脐橙可快速杀梢,减少木虱的食物来源,有效控制木虱种群数量。

Citrus psyllid,Diaphorina citri Kuwayama,habitually lays eggs on the new tender shoots.It is an important measure to prevent citrus Huanglongbing by applying pesticides to control citrus psyllids in time after disbudding to let out shoot.In recent years,killing new tender shoots by spraying shoot-killing pesticides as an alternative of artificial disbudding has attracted the attention of fruit farmers,which has become a crucial technique for the control of citrus Huanglongbing.In this study,Newhall navel orange was used as the experimental species.Oxyfluorfen solution of different concentrations were sprayed and evaluated to explore their shoot-killing effect and their effect on the habitat distribution of citrus psyllids.Meanwhile,the grading standard of the wilted tender shoots and the method for studying the habitat distribution of psyllids were established.The results showed that oxyfluorfen had a similar shoot-killing effect on navel orange saplings and planting trees.It has a certain shoot-killing effect at the mass concentration of 10 mg/L,and the optimal mass concentration was 40-55 mg/L.It showed quick-acting properties,and it was harmless to citrus leaves and fruits at maturity.The oxyfluorfen solution at the mass concentrations of 40 and 55 mg/L were sprayed on the saplings.After 3 days,the shoot length inhibition rates were 86.1%and 124.7%respectively,and the shoot diameter inhibition rates were 83.8%and 94.8%,respectively.After 7 days,the corrected mortalities of tender shoots were 93.7%and 84.1%respectively,the corrected mortalities of psyllids were 7.8%and 21.4%respectively and the habitat inhibition rates of psyllids were 81.0%and 84.4%,respectively.When the planting tree was sprayed with the oxyfluorfen solution at the mass concentrations of 40 and 55 mg/L,after 3 days,the length inhibition rates to tender shoots were 85.9%and 118.8%respectively,and the diameter inhibition rates were 83.9%and 104.1%,respectively.After7 days,the corrected mortalities of tender shoots were 96.6%and 82.4%,respectively.The wilting of tender shoots can cause the death of psyllid eggs and nymphs.However,it has little effect on adult mortality,but the habitat of adult will migrate.Therefore,the application of oxyfluorfen to navel orange can quickly kill tender shoots,reduce food sources of psyllids,and effectively control the population of psyllids.