鞭角华扁叶蜂允许为害测度与抽样分析

Study on the damage threshold and sampling technique of Chinolyda flagellicornis

为摸索鞭角华扁叶蜂允许为害指标和抽样技术,通过摘叶模拟危害测定其允许为害水平,并开展了鞭角华扁叶蜂的生活史、食叶量、空间分布和抽样技术等研究。结果表明鞭角华扁叶蜂1年发生1代,以老熟幼虫在土中筑土室变为预蛹越夏、越冬,幼虫为害期为5月中旬至7月上旬,虫龄为7龄,滞育期幼虫长达290～330d。饲养观察幼虫平均食叶量为3.64g/条,取叶量集中在5～7龄幼虫占总食叶量的84.26%。柏木鲜叶量与胸径之间的关系为W=551.4772+360.5996D+58.9472D2。摘叶模拟危害各失叶强度的方差和多重比较分析认为:失叶强度35%、50%与对照相比,在胸径、树高生长量方面没有显著差异;材积生长量方面呈显著差异,失叶强度50%时与对照差异显著,35%时与对照没有显著差异。据此,确定失叶强度35%为允许为害水平,以食叶量、鲜叶量来推算为害期幼虫允许为害指标,利用繁殖量公式来推算滞育期幼虫允许为害指标。滞育期幼虫空间分布为聚集分布,分布成分为个体群,利用Iwao模型的α、β值和允许为害指标,确定抽样理论数和序贯抽样模式,对角线法、Z字形法和平行线法抽样没有显著差异。

In order to estimate the damage threshold index and sampling technique of Chinolyda flagellicornis, we conducted studies on their life cycle ,leaf consumption, spatial distribution pattern and sampling technique, through leafpicking simulated damage experiment. The result showed that they breed one generation per year, mature larvae turned into prepupae to live through summer and winter beneath the earth. The period of larvae damage span the mid of May to the first ten days of July, when they are in 7th instar, the diapause period can be 290--330 d. The feeding observation indicates that each larva consumes 3.64 g on average, and 84.26% are consumed by larvae in 5th--7th instar. Fresh leaves quantity and DBH of Cupressus funebris were of the relationship as W = 551. 477 2 ＋ 360. 599 6D ＋ 58. 947 2D2. The analysis of variance and multiple comparison of leaf-picking simulated damage experiment reveal that 35% and 50% loss of leaves causes no significant difference in the aspects of DBH and height increment. However, the difference in volume increment is remarkable, 50% loss of leaves has large imparity, while the 35% one is not. Thus 35% of leave-loss is confirmed to be the damage threshold level, the damage threshold index of larvae is calculated according to the leaf-consumption and fresh leaves quantity, and the one of larvae in diapause is according to the formula of the propagation amount. Its spatial distribution pattern is characterized by aggregated distribution of the diapause larvae, and the ental constituent of distribution is individual population, the theoretical sampling number and sequential sampling method are fixed according to the value of α and β in Iwao＇s model and the index of damage threshold. No significant differences are noticed between the use of diagonal, Z-shaped and paralleled measurements.