화살깍지벌레 여름성충의 산란수를 항온조건에서 조사하였다. 총 산란수는 온도가 증가함에 따라 29℃까지는 증가하였고 그 후 감소하였다. 최대 산란수는 암컷당 평균 29℃에서 254.5개로 나타났다. 성충은 주기적인 산란활동을 보였으나, 그 형태는 온도에 따라 달랐다. 처리온도 25℃와 29℃에서는 3개 이상의 산란주기가 나타났다. 다른 온도에서는 두 번째 산란주기가 불완전하거나 확실하지 않았다. 첫 번째 산란주기 산란수는 온도에 따라 유의한 차이를 보였으며 25℃와 29℃에서 많았다. 또한 이후 산란주기의 산란수도 13℃, 17℃ 및 21℃에서는 25℃와 29℃ 보다 낮았다. 부화약충의 암컷 : 수컷 성비는 13℃, 17℃, 25℃, 29℃, 33℃에서 각각 1 : 0.48, 1 : 4.79, 1 : 2.48, 1 : 1.85, 1 : 0.56로 조사되었다.

Arrowhead scale, Unaspis yanonensis, is a serious scale insect pest of citrus in Jeju. The sticky taping of 1.0 cm diameter twig was a good survey method for arrowhead scale crawler. There are three times crawler occurrence season - late May to early July, late July to middle September and late September to late October. But the third occurred crawlers are all died during overwintering in open-field groves. This study was conducted to provide information on efficient sampling plan for arrowhead scale within the tree. Twig and fruit was fit for secondary sample unit by two-stage variance analysis. Both sample number per tree (primary sample unit) was eight twigs or fruits. Taylor’s power law was better described the distribution characteristic of arrowhead scale than Iwao’s patchiness regression. The slope of both linear regressions was greater than “1” which means aggregative distribution pattern. Minimum sample size to estimate the density was calculated using by two parameters of Taylor’s power law. To estimate the mean density on twig and fruit by binomial sampling plan, the optimum tally threshold was 5 and 7, respectively.

To understand the oviposition biology of arrowhead scale, Unaspis yanonensis (Kuwana) (Homoptera: Diaspididae), the longevity and fecundity of the overwintered females were examined at various temperatures (16, 20, 24, 28, and 32℃). The total fecundity increased with rising temperature, showed a maximum of 260.9 crawlers per female at 24℃, and then declined thereafter. Females showed a periodical oviposition activity. The 1st cycle fecundity was identified at all temperatures examined, and was not significantly different between 16 and 28℃. However, the 2nd cycle fecundity and later cycle fecundity were much lower at 16, 20, and 32℃ than those at 24 and 28℃. The pre-oviposition period ranged from 49.0 d at 16℃ to 19.7 d at 32℃, and was the shortest 19.4d at 28℃. The linear lines of mean development rates (1/mean pre-oviposition period) against temperatures provided the estimate of low-threshold temperature 8.7℃ for pre-oviposition stage and the thermal constant of 358.1 DD. The lower threshold temperature and thermal constant for the completion of U. yanonensis pre-oviposition period well predicted the first crawler occurrences in the fields.