밀양에서 월동하는 애멸구 개체군의 월동생태에 관한 정확한 자료를 얻고자 본 연구를 수행하였다. 월동 애멸구의 영구성 비율은 12월상순에 4령충(약 60%)이 가장 많았으며, 다음은 3령충(약 30%), 5령충(약 6%), 2령충(약 3.4%), 성충 및 1령충 순서였다. 이러한 월동 애멸구의 영구성 비율과 순서는 채집시기에 따라 변화였으며, 그 결과 3월상순에는 5령충(47-50%)이 가장 많았고, 다음은 4령충(44-46%)이었으며, 4월상순에는 성충이 약 75-81%를 차지하였다. 월동 애멸구의 발육상황을 수치로 나타낸 평균령기는 월동기간동안 계속하여 증가하는 경향이었으며, 채집년도간 평균령기의 차이는 연도간 월동기간중의 온도차이에 따른 월동 애멸구 영구성 비율의 차이에 따른 결과였다. 애멸구의 체중도 월동기간동안 계속하여 증가하였다. 월동기간동안 애멸구으 채집밀도는 보리밭보다 휴반에서 월등하게 높았다. 월동기간동안 애멸구 약충기생봉에 의한 기생률은 평균 약 21%였다.
This study was conducted to determine the winter ecology of the small brown planthopper (SBPH), laodelphax striatellus Fallen, in Milyang, east Kyungsangnamdo province. The age distribution in the overwintering SBPH population varied according to collection dates. In early December, the population distribution was 60% 4th instar, 30% 3rd instar, 6% 5th instar, 3.4% 2nd instar with very few adults and 1st instar. In early March 5th instars had the highest propotion (47-50%) with 4th instar 44-46%. In early April the adult population was 75-81% of the population. The averaged nymphal instar converted the age distribution of he overwintering SBPH in to the into the numerical values tended to increase continuously. However, there were some differences in the averaged nymphal instar of overwintering SBPH annually and these differences resulted from different age distribution of the overwintering SBPH due to different annual temperature fluctuations during overwitering periods. The weight of the overwintering SBPH increased continuously during overwintering periods. The collection density of the overwintering SBPH population was significantly higher on the levee than in the barley field. Percent nymphal parasitism by haplogonatopus atratus in the overwintering SBPH population averaged about 21% regardless of overwintering years.