Nanini F, Maggio D H, Ferronato P, Rugno G, Yamamoto P T, Corrêa A S
Depto de Entomologia e Acarologia, ESALQ - Univ de São Paulo, Piracicaba, SP 13418-900, Brasil.
Neotrop Entomol. 2019 Dec;48(6):927-933. doi: 10.1007/s13744-019-00721-5. Epub 2019 Nov 9.
Diaphorina citri Kuwayama is the vector of the pathogenic bacteria Candidatus Liberibacter spp., the causative agent of Huanglongbing (HLB), the most serious disease of citrus worldwide. Because predatory insects have been historically neglected in biological control programs for D. citri, the impact of generalist predators on D. citri population densities is little understood. A useful tool to evaluate the dynamics of predator-prey interactions is molecular analysis of predators' gut content. We constructed a specific molecular marker to detect D. citri DNA in the gut content of predator insects, for use in estimating the predation rate of field-collected predators in citrus orchards on D. citri. Bioassays of the DNA half-life detection time were carried out with two predatory species, the ladybird beetle Hippodamia convergens Guérin-Méneville and the lacewing Chrysoperla externa (Hagen). The D. citri DNA half-life detection time (DT) was 6.11 h for H. convergens and 5.46 h for C. externa. One hundred and seven field-collected predators were used for gut-content analysis (52 larvae/adults of ladybirds and 55 larvae of lacewings). The assays showed that 17.3% of ladybirds but no lacewings tested positive for D. citri DNA. These results show that generalist predators can contribute to biological control of D. citri and should be considered for use in pest management programs in citrus orchards.
柑桔木虱（Diaphorina citri Kuwayama）是致病细菌“Ca. Liberibacter spp.”的传播媒介，该细菌是黄龙病（HLB）的病原体，是全球柑桔最严重的病害。由于捕食性昆虫在柑桔木虱的生物防治计划中一直被忽视，因此对多食性捕食者对柑桔木虱种群密度的影响了解甚少。评估捕食者与猎物相互作用动态的一个有用工具是对捕食者肠道内容物进行分子分析。我们构建了一种特定的分子标记，用于检测捕食性昆虫肠道内容物中的柑桔木虱DNA，以估算柑桔园中田间采集的捕食者对柑桔木虱的捕食率。对两种捕食性昆虫——瓢虫龟纹瓢虫（Hippodamia convergens Guérin-Méneville）和草蛉（Chrysoperla externa (Hagen)）进行了DNA半衰期检测时间的生物测定。龟纹瓢虫的柑桔木虱DNA半衰期检测时间（DT）为6.11小时，而草蛉为5.46小时。使用107只田间采集的捕食者进行肠道内容物分析（52只瓢虫幼虫/成虫和55只草蛉幼虫）。检测表明，17.3%的瓢虫检测出柑桔木虱DNA呈阳性，但草蛉均未检测出阳性。这些结果表明，多食性捕食者有助于对柑桔木虱进行生物防治，应考虑将其用于柑桔园的害虫管理计划。
