밤재배원에서 발생하는 밤바구미를 물리적으로 방제하기 위하여 침지처리 온도 및 시간별로 유충에 대한 방제효과와 밤 종실에 미치는 성 분변화 등을 조사하였다. 밤 종실내의 밤바구미 유충을 방제하기 위하여 다양한 온도조건(30, 35, 40, 45, 50℃)과 시간별(1, 2, 3, 5, 7, 10, 15, 22, 24시간)로 처리하여 방제활성을 조사하였다. 침지처리에 의한 밤 종실의 변화 조사로는 밝기(lightness), 적색도(redness), 황색도(yellowness) 등의 색도의 변화와 발아율, 부패율과 같은 생리적 변화, 경도(hardness)와 같은 물리적 변화, 수분함량과 유리당, 탄닌과 같은 성분변화를 조사 하였다. 침지처리를 이용한 밤바구미 유충의 방제 효과는 30℃에서 2시간 후부터 70%이상의 살충효과를 보였으며, 7시간 후부터는 100% 방제 효과를 보였다. 40℃에서는 2시간 후부터 90%의 효과를 보였으며, 45℃ 이상에서는 침지 처리 1시간 후부터 90%이상의 살충효과를 나타내었 다. 밤 종실에 대한 색도의 변화는 30℃와 35℃에서는 큰 유의차가 없었으나 40℃ 이상의 온도에서는 시간이 증가할수록 밝기, 적색도, 황색도 에 영향을 미쳤다. 발아율의 경우 침지처리에 대한 영향은 크지 않은 것으로 조사되었으나, 40℃ 이상의 온도조건에서는 침지시간이 증가할수록 부패율이 증가하는 것으로 조사되었다. 경도는 온도와 침지처리 시간이 증가할수록 감소하였다. 침지처리에 의한 종실 성분의 변화는 온도와 침 지처리 시간이 증가할수록 유리당함량이 감소하였다. 이상의 결과들은 적절한 온도와 시간조건에서의 침지처리가 밤바구미 유충 방제에 효과적 이며, 밤 종실의 상품성에도 큰 영향을 미치지 않음을 보여주었다. 따라서 본 연구결과는 밤 종실의 침지조건을 선별하는데 기초자료로 사용될 수 있을 것으로 기대된다.

Measurements were made on morphology of each developmental stages of the chestnut weevil, Curculio sikkimensis, reared in the laboratory and field from 2003 to 2006. The size of egg was 0.8±0.03 ㎜. The escaping larvae were measured, in average, as 98 ㎎ in body weight, 10.65 and 3.99 ㎜ in body length and width, and 1.70 ㎜ in head width. Pupal size of female and male was 7.01 and 6.53 ㎜, respectively. The fresh weight (0.343 g), body length (7.76 ㎜) and width (3.38 ㎜), and head width (1.60 ㎜) of female adults were significantly bigger than those (0.268 g, 7.14 ㎜, 3.01 ㎜ and 1.37 ㎜, respectively) of male adults. Proboscis length (6.53 ㎜) and antennal length (5.47 ㎜) of female was also significantly longer than those (3.56 and 4.63 ㎜, respectively) of male. The larvae of C. sikkimensis overwintered for 1~3 years and their body weight, body length, and body width were decreased. The ratio between proboscis length and body length, the basipodite position attached to the proboscis, and shape of the sex organ on the abdominal end could be used to discriminate sexes.

This study was conducted to investigate the numerical measurements of chestnut weevil, Curculio sikkimensis, reared in the lab and outdoor field from 2003 to 2006. Numerical measurements were calculated for the sex ratios, fresh weight, body length and width, head width, proboscis length, and antennal length. The female adult was bigger than male in fresh weight, body length and width, head width, proboscis, and antennal length. The size of egg was showed 0.8±0.03mm (n=20). Larval instars was measured 98 mg in body weight, 10.65 and 3.99 mm in body length and width, 1.70 mm in head width. Pupal size was also measured as 7.01±0.65mm in female, 6.53±0.48mm in male. The larva of C. sikkimensis overwintered through 3 years and the size of body weight, body length, and body width were decreased.

This study was conducted to investigate the numerical measurements of chestnut weevil, Curculio sikkimensis, reared in the lab and outdoor field from 2003 to 2006. Numerical measurements were calculated for the sex ratios, fresh weight, body length and width, head width, proboscis length, and antennal length. The female adult was bigger than male in fresh weight, body length and width, head width, proboscis, and antennal length. The size of egg was showed 0.8±0.03mm (n=20). Larval instars was measured 98 mg in body weight, 10.65 and 3.99 mm in body length and width, 1.70 mm in head width. Pupal size was also measured as 7.01±0.65mm in female, 6.53±0.48mm in male. The larva of C. sikkimensis overwintered through 3 years and the size of body weight, body length, and body width were decreased.

This study was conducted to investigate the seasonal occurrence of chestnut weevil, Curculio sikkimensis. The chestnuts infected by the weevils were collected from Gongju, Buyeo, and Cheongyang in Chungnam Province, Republic of Korea. Investigation was focus on the escape period of chestnut weevil larvae from the fruits, invading time and vertical distribution in soil, survival rates of larvae during overwintering, emergence period, emergence rate, and sex ratio and longevity of adults. For precocious species, larvae escaped the chestnut from the mid-September to the early-October, middle species and slow species, were escaped from the late-September to the mid-October and from the early-October to the mid-November. After escaping from the chestnut fruits all of the larvae burrowed into the soil within 35 minutes. Overwintering larvae inhabited in the range of 0~48 ㎝ from the soil surface and highly distributed in the range of 18~36 ㎝. The 74.1% of wintering chamber were distributed within 18~36 ㎝ from the surface. Survival rates observed were 38.0% in 1st year, 16.0% in 2nd years, and 2% in 3rd years, respectively. Seasonal occurrence period of C. sikkimensis was from the early-Aug. to early-Oct. and the optimal occurrence period was the early and mid-Sept. Emergence rate decreased to 8.4% in 1st year, 3.6% in 2nd years, and 0.8% in 3rd years, respectively. Sex ratio was showed in the range of 0.51-0.55. It is female biased ratio. Longevity of adults was 9.9 days for female and 8.9 days for male.

전남지방의 밤 집단재배단지에서 피해가 확대되고 있는 밤바구미의 피해율, 발생시기, 토중의 월동부위, 월동후의 사충율의 변이에 대한 시험을 계획한 바 다음과 같은 결과를 얻었다. 1. 전남지방 밤 단지의 밤바구미 피해율은 담장 , 광양 , 승주 였으며 이 지역은 참나무류가 많이 혼재되어 있었다. 2. 월동유충의 약 가 1년차에 우화되었고, 가 2년차에, 그리고 가 3년차로 계속 월동중이었다. 3. 밤바구미의 우화시기는 7월 중순부터 9월 중순까지였고 그 최성기는 8월 중순에서 9월 상순이었다. 4. 밤바구미 피해종실로부터의 유충 탈출시기는 10월 상순부터 11월 상순이었다. 5. 밤바구미의 난기는 5.95일, 용기는 17.17일, 성충의 수명은 암컷 9.10일, 숫컷 7.03일 이었으며 유충기간은 매우 다양하여 측정하기 어려웠다. 6. 밤바구미는 월동유충은 상중 에 많이 분포하였다. 7. 월동후 일수경과에 따른 사충율과는 고도의 유의상관관계가 인정되었다.