Abstract
This study was carried out to select effective preventive pesticides against pine wilt disease caused by pinewood nematode (PWN), Bursaphelenchus xylophilus on trunk injection. 1,000 fold aquatic solution of abamectin 1.8% EC and emamectin benzoate 2.15% EC were lower mortality (7.3% and 8.3% respectively) against PWN on 1 day after treatment. However effects of abamectin 1.8% EC, emamectin benzoate 2.15% EC, fosthiazate 30% SL and fenitrothion 30% SL were inhibited the reproduction of PWN over 99.6% in Botrytis cineria media. Effect of trunk injection of abamectin 1.8% EC and emamectin benzoate 2.15% EC at the rate of $10\;m{\ell}$ per 10 cm in diameter of breast height (DBH) on mortality of Japanese black pine, Pinus thungergii by inoculated PWN was 0% and 3.3%, respectively at the applied year however when injection of fosthiazate 30% SL were treated with the rate of $5\;m{\ell}$ per 10 cm tree DBH, mortality of tree was 63.3%. Abamectin 1.8% EC and emamectin benzoate 2.15% EC was showed high preventive efficacy representing >90% against PWN at the following year. PWN preventing efficacy of trunk injection was lower in naturally occurred area (mortality of pine tree in control was 11.7% at the first year) of PWN than artificially infected site (mortality of pine tree in control was >76.7% at the first year), PWN preventing efficacy of trunk injection of abamectin 1.8% EC and emamectin benzoate 2.15% EC at the rate of $10\;m{\ell}$ per 10 cm in DBH was 91.5% and 82.9%, respectively, at the applied year and 89.5% and 82.6% respectively at the following year in PWN naturally occurred site. Control efficacy by trunk injection of abamectin 1.8% EC and emamectin benzoate 2.15% EC was more higher in 10 fold dilution with 10 fold high amount of aquatic solution than no dilution with 10 fold less amount of aquatic solution. The preventive effect of trunk injection of abamectin 1.8% EC and emamectin benzoate 2.15% EC at the rate of $5\;m{\ell}$ per 10 cm in DBH was showed 100% at the applied year in PWN inoculated tree.
나무주사를 통한 소나무재선충병 예방 효과가 우수한 약제를 선발하기 위하여 실험을 수행하였다. Abamectin 1.8% 유제와 emamectin benzoate 2.15% 유제 현탁액에서 소나무재선충은 1일 후에 7.3%와 8.3%의 낮은 치사율을 보였다. 그러나 잿빛곰팡이균 배지상에서 소나무재선충 증식억제 효과는 abamectin 1.8% 유제와 emamectin benzoate 2.15% 유제, fosthiazate 30% 액제, fenitrothion 30% 액제에서 99.7% 이상을 나타내었다. 곰솔에 대한 나무주사 실험 결과 소나무재선충인공 접종지에서는 abamectin 1.8% 유제와 emamectin benzoate 2.15% 유제의 경우 흉고직경 10 cm당 $10\;m{\ell}$ 주입 시 당년도 고사주율이 0%와 3.3%였으나 fosthiazate 30% 액제를 흉고직경 10 cm당 $5\;m{\ell}$ 주입 시 63.3%의 고사주율을 보였다. 2년째에도 abamectin 1.8% 유제와 emamectin benzoate 2.15% 유제는 90%이상의 방제효과가 있었다. 무처리구의 발병율이 낮은 소나무재선충병 자연 발생지에서 나무주사 효과는 소나무재선충을 인공접종 시킨 곳에 비하여 방제가가 낮게 나타났으나 흉고직경 10 cm당 $20\;m{\ell}$ 주입 시 나무주사 당 년도에 abamectin 1.8% 유제와 emamectin benzoate 2.15% 유제의 방제가는 91.5%와 82.9%로 나타났고, 2년차에도 89.5%와 82.6%의 방제가를 보였다. Abamectin 1.8% 유제와 emamectin benzoate 2.15% 유제를 원액으로 처리한 것과 10배 희석하여 원액처리보다 10배 많은 양을 나무주사한 경우 물량이 많은 처리에서 방제효과가 높았다. 소나무재선충 인공접종 처리지에서 abamectin 1.8% 유제와 emamectin benzoate 2.15% 유제는 흉고직경 10 cm당 $5\;m{\ell}$ 주입 시에도 소나무재선충병 예방효과가 100%있었다.
