A Study on the Ecology of the Pine Gall-Midge (Thecodiplosis japonensis Uchida et Inouye)...(1) - The Percentage of Larval Falling to the Ground and The Degree of Gall-Forming -

솔잎혹파리의 생태조사(生態調査) (1) - 유충낙하율(幼虫落下率) 및 충영형성률(虫癭形成率) -

As a series of studies on the behaviour of Pine gallmidge (Theccdiplosis japonensis Uehida ei Inoaye), the season of the larval hibernation in winter as well as the season of the attack of adults on pine needles in the vicinity of Seoul were observed, and following results were obtained. 1. The larvae get out of the galls and fall into the ground for the hibernation commencing from the end of September and finishing by the end of January of the next year. 2. About 76% of the whole larvae fell down during the month of November. 3. The frequency and the duration of raining mainly influenced the larval falling into the ground but temperature, humidity and the quantity of rainfall was not likely influence upon it. 4. As many as 47,000 larvae were counted per 1.5 square meter of the ground under the crown of the damaged trees. 5. When pine needles were isolated by fine linen-net-bag to keep the needles from the oviposition of the adults of the insect, at six different season; -i.e. 30th, May, 6th, 10th, 15th, 25th, and 30th June, the percentages of the damage were 80%, 50%, 36%, 19%, 20% and 1% respectively, while the damage of the control was 91%.

이것은 솔잎혹파리의 생태(生態)를 밝히고저 서울지방(地方)에서의 시기별유충낙하율(時期別幼虫落下率)과 시기별피해율(時期別被害率)을 조사(調査)한 것이다. 1. 솔잎혹파리의 유충(幼虫)이 피해엽(被害葉)의 충영(虫癭)으로 부터 지표(地表)에 떨어지는 시기(時期)는 9월(月) 하순(下旬)부터 다음해 1월하순(月下旬)까지 이다. 2. 솔잎혹파리 유충(幼虫)은 11월중(月中)에 가장 많이 낙하(落下)하며 전체낙하수(全體落下數)의 76%가 11월(月)에 낙하(落下)하였다. 3. 솔잎혹파리 유충(幼虫)은 강우시(降雨時)에 많이 떨어지며 온도습도(溫度濕度), 강우량(降雨量)은 유충낙하수(幼虫落下數)에 상관(相關)이 없다. 4. 피해도(被害度)가 평균(平均) 70%인 피해임수관하(被害林樹冠下)에서 $1.5m^2$당(當) 47,000여(餘) 마리의 유충(幼虫)이 낙하(落下)하였다. 5. 솔잎혹파리의 시기별(時期別) 피해율(被害率)은 대조구(對照區) 91%, 5월(月)30일구(日區) 80%, 6월(月)6일구(日區)50%, 6월(月)10일구(日區)36%, 6월(月)15일구(日區)19%, 6월(月)25일구(日區)20%, 6월(月)30일구(日區)1%이었다.