室内饲养梨小食心虫幼虫脱果动态

为掌握不同果实室内饲养梨小食心虫Grapholita molesta(Busck)的效果及幼虫脱果的动态,以新红星苹果、富士苹果和大金星山楂饲养梨小食心虫,逐日记载幼虫脱果数量,并进行逻辑斯蒂(logistic equation)曲线拟合。结果显示,相同接卵数和相同饲料重量的情况下,3种饲料得到的幼虫数量高低次序为:新红星苹果>红富士苹果>大金星山楂。其中,新红星苹果每千克产虫量为27.7头,显著高于其它两种饲料。经逻辑斯蒂方程拟合可知,两种苹果幼虫脱果各时期及盛期历期相差较小;而以山楂饲喂的幼虫脱果各时期均比苹果饲喂的梨小食心虫提前4⁵ d,但盛期历期均为6 d左右。由此可知,梨小食心虫幼虫脱果动态可能与寄主水果种类关系较大,而与同种水果不同品种关系较小,这也可能是造成梨小食心虫各代发生重叠及混栽园受害严重的原因。因此,本研究不仅对在室内饲养梨小食心虫具有指导作用,且为测报防治田间脱果幼虫时间提供依据。

Dynamics of the emergence of Grapholitha molesta （Busck） larvae from fruit under laboratory conditions

In order to determine how best to rear Grapholitha molesta （Busck） larvae in captivity and understand the dynamics of mature larvae emerging from fruit, we inoculated the same wet-weight of three common fruits （ two apple varieties and one hawthorn variety） with the same number of G. molesta eggs and fitted a logistic equation to the number of mature larvae that emerged. The results show that the most larvae emerged from Starkrimson apple followed by Fuji apple then Da jinxing hawthorn. There was little difference in the emergence time of larvae from the two apple varieties but larvae emerged from the hawthorn fruit 4-5 days earlier than from either apple variety. The average emergence time was about 6 days. 27.7 larvae emerged from a kilogram of Starkrimson apple, significantly more than from the two other kinds of fruits. The dynamics of mature larvae emergence may be closely related to fruit species, but appear to have little relationship to the variety of the same fruit species. This may be the reason for the generational overlap and increased crop damage often caused by this pest in mixed orchards. These results not only provide guidelines for the captive rearing of G. molesta but also for controlling this pest in orchards.