苹果蠹蛾的蛀果与脱果特性

苹果蠹蛾Cydia pomonella(L.)是我国重大植物检疫性有害生物,对苹果属以及梨属的水果生产造成严重的危害。该虫以初孵化的1龄幼虫蛀入果肉,在果实内部取食为害并完成发育,老熟幼虫在黑暗中离开果实并寻找场所结茧化蛹。为掌握苹果蠹蛾幼虫进入及脱出果实时的行为特性,从而为实施有效的防治措施提供基础信息,本文在内蒙古格棱布楞滩对苹果蠹蛾幼虫的蛀果与脱果特性开展了详细研究。取得的主要研究结果如下:1)在苹果蠹蛾种群密度较高的情况下,单个果实平均蛀孔数可达5.25个,初期蛀入果实的幼虫在2～8头之间;2)苹果及梨蛀果中的幼虫数量与蛀孔数无关,虽然果实上的最高蛀孔数可达14个,但一般情况下受害果实中的幼虫数不超过3个;3)当果实表面蛀孔数较多时(苹果超过5个,梨超过2个),苹果蠹蛾幼虫向种室钻蛀的行为发生偏移,通常转入在果肉中为害;4)落果后5d内,落果内的幼虫近半数脱果(43.1%),落果后15d内,落果内的幼虫几乎全部脱果(99.9%);5)在脱果幼虫中,94%选择在夜间脱果,6%在日间脱果;6)至试验结束,蛀果中还有64%的幼虫滞留。以上研究结果表明,在种群密度较高的情况下,苹果蠹蛾幼虫存在激烈的种内竞争;及时清除苹果蠹蛾幼虫蛀果后造成的落果对未脱果幼虫有很好的防治效果。

The behavior of Cydia pomonella larvae both inside and outside fruit

The codling moth Cydia pomonella （L.） is an important quarantine pest in China that inflicts serious damage to apple and pear crops. The newly hatched larvae bore into the fruit, and eat the seed to complete the larval stage. The mature larvae leave the fruit at night to find suitable sites to form cocoons. In order to better understand the behavioral traits of codling moth larvae and provide basic information to improve control of this pest we studied the behavior of codling moth larvae in Gelingbulongtan in Inner Mongolia. The main results were as follows：（1） at high population densities, the average numbers of holes bored in fruit was 5.25 and the initial number of larvae that entered was 2—8; （2） The number of larvae in damaged fruit had no relationship to the numbers of holes bored in the fruit. In general, damaged fruit contained less than 3 larvae. （3） When the number of holes in fruit was high （on apples 5, on pears 2） larvae stopped eating seeds and began to eat pulp. （4） 43.1% of larvae left damaged apples within 5days and 99.9% of them left within 15 days. （5） 94% of the larvae left damaged apples at night and 6% of them left during the day. （6） 64% of larvae remained in damaged apples when the study ended. These results indicate that codling moth larvae are subject to intense competition at high population density, and collecting fallen fruit will be an effective control method.