宁夏灵武市沟眶象发生特点

系统调查沟眶象Eucryptorrhynchus chinensis(Olivier)在宁夏灵武市的发生情况和特点发现:沟眶象以成虫和幼虫在土壤中越冬,成虫有2个发生高峰期,越冬结束后以成虫越冬的沟眶象出土出现第1个高峰期,以幼虫越冬的沟眶象经化蛹羽化出土出现第2个高峰期;幼虫危害臭椿根部形成的瘤状物可以作为鉴别沟眶象危害的特征;沟眶象幼虫在土壤中垂直分布范围集中在0～45 cm深土层,约占80%;成虫出土孔集中在距臭椿树干基部75 cm范围内,占88%。据此建议土壤施药化学防治沟眶象时,施药深度不宜低于45 cm,施药点距树干基部水平距离不得少于75 cm,且树周各个方向均需施药。每年10月末沟眶象开始"入土"、翌年4月末开始"出土",在沟眶象"入土"结束后但未冻土之前的11中旬和土壤解冻之后但尚未"出土"前的4月中旬,这两个时期土壤施药防治效果较好;防治沟眶象的同时,还应适时采取打孔注药、熏蒸等措施防治臭椿(Ailanthus altissima(Mill.)Swingle)树干内的臭椿沟眶象Eucryptorrhynchus brandti(Harold)。

Occurrence and life-history of Eucryptorrhynchus chinensis in Lingwu, Ningxia

A systemic investigation of the occurrence and life-history of Eucryptorrhynchus chinensls （Olivier） in Lingwu, Ningxia, found that this species overwinters as adults and larvae in the soil. There are two peaks of adult abundance, the first when overwintering adults emerge and the second when adults emerge from overwintering pupae. E. chinensis larvae damage the roots of Ailanthus altissima （ Mill. ） Swingle, stimulating the formation of root nodules that are diagnostic indicators of damage caused by this pest. A survey of the vertical distribution of larvae and soil-dwelling adults indicated that about 80% of larvae were found between the soil surface and a depth of 45 cm. In terms of horizontal distribution, 88% of E. chinensis were found in the zone from the base of the trunk to a radius of 75 cm. Based on these results, it should be most cost-effective to apply pesticide to a depth of not less than 45 cm below the soil surface and to a distance of at least 75 cm from the base of each trunk. At the end of October and April of the following year E. chinensis began to burrow into the soil. Therefore, it would be better to apply pesticide in mid-November and mid-Aprll when the soil is unfrozen. Apart from preventing E. chinensis damage to roots, injection and fumigation are two measures that can be used to kill Eucryptorrhynchus brandti （Harold） inside the Ailanthus altissima trunk.