Abstract
The newly hatched nymphs of brown planthopper(BPH) were reared individually for two generations in test tubes, where young rice seedling was planted on agar solution, at $30^{\circ}C,\;25^{\circ}C\;and\;20^{\circ}C\;with\;95\%,\;75\%,\;65\%\;and\;35\%$ R.H. Effects of $30^{\circ}C$ on the development of BPH when compared with those of $25^{\circ}C$ are followings. Egg period, nymphal period, and adult longevity were shortened. Nymphal mortality was increased and the number of oviposited eggs was decreased. Hatchability was zero per cent because the eggs were either unfertilized or died before finishing the development. At the low temperature of $20^{\circ}C$, in comparision with $25^{\circ}C$, the developmental period of nymphs and eggs was considerably lengthened, and adult longevity was shortened, the number of oviposited eggs was decreased. The nymphal mortality was higher at high relative humidity $(above\;75\%\;RH)$ than that at low relative humidity $(under\;65\%\;RH)$. Under the condition of high relative humidities, the adult longevity was shortened, and the number of oviposited eggs was decreased.
온${\cdot}$습도가 벼멸구(Nilaparvata lugens stal)의 생육에 미치는 영향을 알아보기 위하여 30, 25, $20^{\circ}C$의 세 수준의 온도구 내에 습도를 95, 75, 65, $35\%$의 네 수준으로 하여 2세대까지 개체사육한 결과를 요약하면 다음과 같다. 1. $25^{\circ}C$에서 벼멸구의 발육과 비교해 볼 때 $30^{\circ}C$에서는 난기간, 약충기간, 성충수명이 단축되었고 약충의 사망률은 증가하였으며 산란수는 크게 감소하였다. 또한 산란된 난은 수정이 되지 않았거나 배자발육도중 죽음으로서 부화가 전혀 이루어지지 않았다. 2. $25^{\circ}C$와 비교하여 $20^{\circ}C$의 저온에서는 난과 약충 발육기간이 상당히 지연되었고 성충수명이 짧아졌으며 산란수가 크게 감소하였을 뿐 아니라 부화율도 감소하였다. 3. 약충의 치사율은 RH $75\%$ 이상의 비교적 높은 습도조건에서 높았으며 또한 다습조건에서는 성충의 수명이 단축된 결과 산란수가 크게 감소하였다.