Seasonal Occurrence, Host Preference and Hatching Behavior of Eriococcus lagerstroemiae

주머니 깍지벌레의 발생소장, 기주선호성 및 부화습성

This study investigated seasonal occurrence, host preference and developmental characteristics of E. lagerstroemiae was most likely to have two generations a year with first occurrence of adults form late April to late may and second from late August to late October including 2 peaks in early May and late August, respectively. Overwintering stages were mostly eggs and larvae and its composition rate was 57.1% of eggs and 42.9% of larvae. Host plats investigated were 7 species 7 families and most preferred species were Lagerstroemia japonica and Diospyros kaki. As morphological characteristics of E. lagerstroemiae, sized of length/sidth were 0.29/0.16 mm for the egg. 0.41/0.16 mm for the first instar larva, 0.96/0.47 mm for the male adult. Number of eggs deposited per female adult was 221.9 individuals. Hatching rate at various temperatures was above 90% at below $30^{\circ}C$. Egg periods were also short\ened with increase of temperatures at below $30^{\circ}C$ but decreased to 56.3% at $35^{\circ}C$. Egg periods were also shortened with increase of temperatures at below $30^{\circ}C$. Hatching rate was not affected by photoperiods but egg periods were shortened with increase of day length.

감나무와 가로수 및 정원수로 식재되어 있는 배롱나무에 극심한 피해를 주고 있는 주머니 깍지벌레의 발생상태에 관하여 연구한 결과 주머니깍지벌레는 연2회 발생하며 1세대 성충은 4월 하순~5월 하순까지로 발생최성기는 5월 상순이었고, 2세대는 8월 하순부터 10월 상순까지로 최성기는 8월 상순이었다. 월동충태 구성은 난이 57.1%, 유충이 42.9%로 주로 난과 유충으로 월동하였다. 기주식물은 배롱나무 등 7과 7종이 조사되었으며 그중 배롱나무와 감나무를 선호하였다. 각 층태별 크기는 난의 길이가 0.29/0.16mm, 1령 유충은 체장/폭이 0.41/0.16mm, 2령 유충 0.96/0.45mm, 자성충 1.87/1.38 mm, 웅성충 0.93/0.47 mm이었으며, 산란수는 평균 221.9개이었다. 온도에 따른 난기간은 $30^{\circ}C$이하에서는 온도가 높을수록 짧아졌으나 $35^{\circ}C$에서는 $30^{\circ}C$의 6.8일에 비해 12.0일로 길어졌고 부화율은 $30^{\circ}C$이하에서 90% 정도로 높았으나 $35^{\circ}C$에서는 56.5%로 낮아졌다. 광주기에 따른 난기간은 광기간이 길수록 짧아지는 경향이었으며 부화율은 평균 98%이상으로 거의 영향을 받지 않았다.