菠萝粉蚧和新菠萝灰粉蚧γ-射线辐照处理研究

Effects of γ-ray irradiation on Dysmicoccus brevipes and Dysmicoccus neobrevipes

菠萝粉蚧Dysmicoccus brevipes(Cockerell)和新菠萝灰粉蚧Dysmicoccus neobrevipes(Beardsley)是菠萝等热带水果上的重要害虫,是我国进出境水果贸易中均需要检疫处理的对象。为了建立适合菠萝等水果上这两种粉蚧的检疫处理技术,本研究采用80、130、180、230和280 Gyγ-射线辐照处理了两种粉蚧的若虫和成虫。结果表明,两种粉蚧对γ射线的剂量反应基本一致,表现为随虫龄增大对辐照的耐受性增强,以雌成虫为最强。采用230Gy辐照若虫,两种粉蚧各若虫均不产生F1代活虫体,并且菠萝粉蚧1龄若虫在该剂量下不能发育至雌成虫。以230 Gy辐照成虫,两种粉蚧均产生F1代雌成虫,但不产生F2代。以240 Gy剂量大规模辐照处理3龄若虫和雌成虫,表明该剂量足以阻止两种粉蚧繁殖,该剂量可作为这两种粉蚧辐照处理的参考指标。

Dysmicoccus brevipes（Cockerell） and D. neobrevipes （Beardsley） are important pests requiring quarantine treatment at entry and exit ports for tropical fruit such as pineapples etc. In order to establish an effective treatment method for these two mealybugs, Cobalt-60 gamma ray target doses of 80, 130, 180, 230 and 250 Gy were used to irradiate immatures and adults of both species to find the most tolerant stage and the optimal dose range for quarantine treatment. The responses of each species to irradiation displayed a similar pattern. Tolerance to irradiation in both species increased with advancing life stage, with adults being the most tolerant stage. At 230 Gy, no living offspring were produced by surviving female adults irradiated as nymphs, and no irradiated 1st instar nymphs of D. brevipessurvived to adulthood. Although female adults of both D. brevipes and D. neobrevipes, irradiated with 230Gy, produced an F1 generation but no F2 generation was produced. In a large-scale irradiation test, no surviving female adult developed from either 3rd instar nymphs, nor did adults irradiated at 240 Gy produce offspring, indicating that a dose of 240 Gy or above is sufficient to prevent the reproduction of these two mealybug species.