6-8月苹果园金纹细蛾虫龄分布

Instar Distribution of Lithocolletis ringoniella in Apple Orchard in June to August

为了进一步了解金纹细蛾的危害特点,掌握幼虫在虫疤内的变化规律。定期采集杨凌地区苹果园中金纹细蛾为害的虫疤叶,在室内解剖分离幼虫,观察各龄幼虫数量时序变化与分布。结果表明,6-8月金纹细蛾幼虫数量变化分为3个阶段,即数量迅速下降期(6月21日到7月3日)、平稳变化期(7月3日到7月19日)和波浪变化期(7月19日到8月31日);金纹细蛾幼虫5个龄期的变化呈马鞍形,即6月27日和8月3日有两个高峰,7月19日和8月23日有两个低谷;金纹细蛾5个虫龄数量时序分布差异显著,比较同一时间不同虫龄差异性,6月21日3龄虫量在最多、显著高于其他虫龄,7月19日各龄虫数量差异均达到显著水平,8月3日5龄虫量最多、为5.8头、显著高于其他虫龄;比较同一虫龄不同时间差异性,1龄虫数量在8月31日最多、与其他日期相比差异达显著水平,2龄虫量在8月31日最多(为7.33头),3龄虫在8月3日数量最多(为8.2头)、显著高于其他日期;4龄虫在7月19日出现零分布,5龄虫在8月31日出现零分布。从各龄幼虫总体平均时序分布差异性来看,同一时间3龄幼虫数量显著高于5龄,其他各龄幼虫间分布差异不显著。

In order to understand the damage of Lithocolletis ringoniella and master the change of lar- vae in scar, leaves with Lithocolletis ringoniella in apple orchard at regular intervals in Yangling were collected and dissected indoor to observe the sequential variation and distribution of each instar. The results showed that the occurrence amount of larvae＇s sequential variation had three phases, rapid de- cline period （ from 21st in June to the third in July ）, smooth change period （from July third to Au- gust 23rd ）, up and down alternately period （from 23rd to 31st in August ）. The variation of five in- stars had two peaks on 21st in June and 23rd in August, also had two troughs on 19th in July and 23rd in August; the temporal distribution of five instars amount differed notably when the date was fixed. The amount of the 3rd instar was the most and significantly more than the others on July 21st; the number of each instar reached the significant level on July 19th; the number of the 5th instar was the most i.e. 5.8 heads on August 3rd for the same instar, the amount of the first instar was the most on August 31st and significantly more than other time; the number of second instar was the most i. e. 7.33 heads on August 3rd; the third instar was 8.22 heads which was significantly more than other time; the forth and fifth instars appeared zero distribution on 19th in June and 31st in August; from the average of instars~ temporal distribution difference, the number of the third instar was significant- ly higher than that of 5th instar in the same period, and there was no significant larvae distribution difference in other instars. The result of this study may provide some guidance on control of Lithocol- letis ringoniella.