Studies on the Effects of the Pine Needle Gall Midge, Thecodiplosis japonensis Uchida et Inouye, on the Growth of the Red Pine, Pinus densiflora Siebold et Zuccarini (I) - Changes in Gall Formation Rate -

솔잎혹파리가 소나무생장(生長)에 미치는 영향(影響)에 관한 연구(硏究)(I) - 충영형성률(虫癭形成率)의 변동(變動) -

Some aspects of the change in the rate of gall formation on the red pine, Pinus densiflora Siebold et Zuccarini, by the pine needle gall midge, Thecodiplosis japonensis Uchida et Inouye, were investigated at the coastal area in Chung Nam-Do from 1977 to 1982, and were analyzed with the nationwide survey data for 2 years from 1980 to 1981. The results obtained were as follows; the gall formation rate in several areas was compared between two consecutive generations. Four regression equations were established, with X as the gall formation rate in N year and Y as that in (N+1) year: 1) Y=11.2+1.15X (r=0.833) for the stands facing north on the phase of insect population increase, 2) Y=14.3+0.82X (r=0.739) for the stands facing south on the phase of population increase, 3) Y=7.3+0.46X (r=0.478) for stands facing north on the phase of population decrease and 4) Y=11.4+0.19X (r=0.086) for stands facing south on the phase of population decrease. After invasion of the pine needle gall midge into a red pine forest, gall formation rate increased for 6 consecutive generations and then decreased to low level within a period of another 6 years.

솔잎혹파리로 인(因)한 소나무의 충루형성율변동양상(蟲瘻形成率變動樣相)을 1977년(年)부터 1982년(年)까지 6개년간(個年間) 충청남도(忠淸南道) 서해안(西海岸)을 위시(爲始)하여 전국(全國)에서 조사(調査)하였다. 1) 지역별(地域別)로 충루율(蟲瘻率)의 증가속도(增加速度)를 양세대간(兩世代間)의 충루율(忠瘻率)의 회귀방정식(回歸方程式)으로 비교(比較)한 바 솔잎혹파리밀도(密度)가 증가중(增加中)에 있는 선단지(先端地)에서는 북향임지(北向林地) ; Y=11.2+1.15X (r=0.833) 남향임지(南向林地) ; Y=14.3+0.82X (r=0.739)로 증가(增加)하고 있었으며 후방지역(後方地域)에서는 북향임지(北向林地) ; Y=7.3+0.46X (r=0.478), 남향임지(南向林地) ; Y=11.4+0.19X (r=0.086)로 밀도(密度)가 감소(減少)되고 있었다. 2) 솔잎혹파리는 새로운 지역(地域)으로 침입(侵入)하였을 때 약(約) 6세대(世代) 동안 충루율(蟲瘻率)이 증가(增加)하고 그후 급격(急激)하게 감소(減少)하는 양상(樣相)을 보이며 이같은 충루율(蟲瘻率)의 변동과정(變動科程)은 약(約) 12세대(世代)에 걸쳐 일어난다.