亚洲柑桔木虱若虫在寄主上的转移和扩散研究

The movement and spread of nymphs of Diaphorina citri Kuwayama on host plants

黄龙病是世界柑桔产业的一种毁灭性病害,亚洲柑桔木虱Diaphorina citri Kuwayama为黄龙病亚洲种和美洲种的媒介昆虫,其成虫和高龄若虫都能传病。本文研究亚洲柑桔木虱若虫在感染黄龙病及健康寄主上的转移和扩散规律,发现3龄及3龄以上若虫在柑桔植株垂直和水平位置的嫩梢之间转移现象十分明显,但在黄龙病植株上转移速度较健康植株慢,且嫩梢间的转移速度受虫口密度的影响,密度越高转移速度越快。在有选择的条件下,水平位置转移过程中若虫更趋向黄龙病植株。此外,在健康寄主上的木虱若虫有明显向植株下部转移的现象,向下部转移的若虫个体数显著高于黄龙病寄主。本文明确了木虱若虫的扩散规律和寄主感染黄龙病对其转移和扩散产生的影响,为柑桔木虱和黄龙病防治提供参考。

Huanglongbing （HLB） is a serious citrus disease worldwide. Diaphorina citri Kuwayama （Hemiptera： Psyllidae） is the insect vector of ＂ Candidatus Liberibacter asiaticus＂ and ＂ Ca. L. americus＂, two bacteria associated with HLB in Asia and South America, respectively. Both adults and late stage nymphs of D. citri can transmit the bacteria. This paper presents the transfer and spread of D. citri nymphs among the young shoots of healthy and HLB - infected citrus. The result showed that late stage psyllid nymphs （3r~ to 5th instar） could make horizontal and vertical transfer among young shoots. On HLB - infected citrus, the speed of transfer was slower than that on the healthy citrus. The density of the nymphs is also a factor affected to the transfer speed. Nymphs transfer faster with the density increased. Psyllid nymphs preferred young shoots of HLB - infected citrus. It was observed that on healthy citrus, more psyllid nymphs transferred downwards to the trunk base. This study confirms the transfer and spread of D. citri nymphs and the effect of HLB - infected citrus. It provides reference for D. citri and HLB prevention and control.