Leong Sui S, Leong Stephen C T, Beattie George A C
Faculty of Agricultural and Forestry Science, Universiti Putra Malaysia Bintulu Sarawak Campus, Nyabau Road, Bintulu 97008, Sarawak, Malaysia.
Institute of Ecosystem Science Borneo, Universiti Putra Malaysia Bintulu Sarawak Campus, Nyabau Road, Bintulu 97008, Sarawak, Malaysia.
Insects. 2022 Oct 20;13(10):960. doi: 10.3390/insects13100960.
The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, transmits ‘Candidatus Liberibacter asiaticus’ (CLas), a phloem-limited bacterium associated with the severe Asian form of huanglongbing (HLB), and the most destructive disease of citrus. The pathogen and the psyllid, both of South Asian origin, are now widespread in citrus regions of Asia and the Americas. There is no cure for the disease. Application of synthetic pesticides, in some instances more frequently than fortnightly, to minimise incidence of ACP in citrus orchards, has not prevented inevitable impacts of the disease in regions of Asia where CLas is present. Despite the inevitable spread of the disease, significant progress has been made in Sarawak since the mid-1990s towards effectively implementing integrated pest management (IPM) programs for stemming the impact of the disease and detrimental consequences of over-reliance on synthetic pesticides. Growers are encouraged to plant pathogen-free trees, remove diseased trees, monitor incidence of the psyllid, and to use pesticides judiciously to reduce their detrimental impacts on natural enemies. Knowledge has been enhanced through research on seasonal incidence of the psyllid, use of mineral oils, development of protocols and iodine−starch test kits for detecting infected trees, PCR for confirming the presence of CLas in symptomatic leaves, methods for monitoring incidence the psyllid, and training extension staff and growers. However, major impediments to increasing the average longevity of trees beyond <5 years in poorly managed orchards, based on marcotting (air layering), and >12 years in well-managed orchards, based on pathogen-free trees, still need to be addressed. These include grower knowledge, marcotting, aggressive marketing of synthetic pesticides, high prices of mineral oils, spray application procedures, and better reliance on natural enemies of the psyllid.
亚洲柑橘木虱（Diaphorina citri Kuwayama）传播“亚洲韧皮部杆菌”（CLas），这是一种局限于韧皮部的细菌，与严重的亚洲型黄龙病（HLB）相关，也是柑橘最具毁灭性的病害。这种病原体和木虱均原产于南亚，目前在亚洲和美洲的柑橘产区广泛分布。这种病害无法治愈。在柑橘果园中，有时每隔不到两周就需施用合成农药，以尽量减少亚洲柑橘木虱的发生，但在存在CLas的亚洲地区，这仍无法避免该病害带来的不可避免的影响。尽管病害不可避免地蔓延，但自20世纪90年代中期以来，砂拉越在有效实施综合虫害管理（IPM）计划以遏制病害影响和过度依赖合成农药的有害后果方面取得了重大进展。鼓励种植者种植无病原体的树木，清除患病树木，监测木虱的发生率，并谨慎使用农药以减少其对天敌的有害影响。通过对木虱季节性发生率的研究、矿物油的使用、检测受感染树木的规程和碘 - 淀粉检测试剂盒的开发、用于确认有症状叶片中CLas存在的PCR、监测木虱发生率的方法以及对推广人员和种植者的培训，相关知识得到了增强。然而，在管理不善的果园中，基于空中压条法，树木平均寿命难以超过5年；在管理良好的果园中，基于无病原体树木，树木平均寿命超过12年，要提高这一寿命仍需解决一些主要障碍。这些障碍包括种植者知识、空中压条法、合成农药的激进营销、矿物油价格高昂、喷雾施用程序以及对木虱天敌的更好依赖。
