前報告에서 西海岸 敷個所의 媒介진딧물 密度가 大關嶺에서의 密度보다 大?로 낮았으나 場所에 따라서는 相當히 높은 事實을 밝힌바 있다. 새감자의 平地生?方式이 現行方式보다 合理的이어서 有利하므로 그 生??系의 確立을 爲한 基礎資料를 얻고져 本調査에 着手하였다. 西海岸畓作地帶에서의 진딧물 發生源은 部落이므로 여기서 얼마나 떨어진 곳이라야 安全하게 씨감자를 栽培할 수 있을 까를 알기 爲하여 全北 金堤部 廣活面 玉浦里를 擇하여 이곳을 中心으로 1.5㎞ 平方地區內 13個所에 東西南北으로 250m 距離를 두고 진딧물 採集器을 設置하여 1968年 7月 21日부터 10月 31日까지 誘集된 진딧물을 每日아침에 採集하여 種名을 밝혔다. 감자바이러스 媒介진딧물이 世界的으로 20種 알려져있는데 우리나라에 있는 것은 10種이며 이 地域에서 發見된 것은 복송아 흑진딧물 (Myzus persicae), 목화진딧물 (Aphis gossypii), 싸리수염진딧물 (Aulacorthum solani), 무우테두리진딧물 (Lipaphis erysimi) 및 국화꼬마수염진딧물 (Macrosiphoniella sanborni)의 5種이었다. 部落中心地에서의 媒介진딧물 密度는 內陸의 水原에서의 그것 보다도 높았으나 여기서 不過 250m만 떨어져도 大關嶺에서의 密度보다 낮아졌다. 그러나 調査地点의 環境에 따라 相當한 差異가 있다. ? 媒介진딧물의 寄主植物이 있는 人家와의 距離에 따라 달라진다. 秋作用 씨감자의 現生?地인 全南의 一毛, 慶南의 駕洛은 內陸의 部落近傍이라서 媒介진딧물 關係로 不適當하다고 본다. 專門家의 植物疫學的 診斷에 依해 西海岸 畓作地帶中 媒介진딧물이 적은 곳을 擇해서 씨감자를 生?한다면 優秀한 씨감자를 量?할 수 있다. 씨감자 不足量 60.000톤을 充足시킨다면 50%增收 (年間 250萬톤)할 수 있어 農家所得增大는 勿論 남는 감자는 澱粉原料로서 端境期에 供給할 수 있으며 一部를 飼料化할 수 있고 優秀한 씨감자는 外國에 輸出 할 수도 있으며 全北 西海岸의 廣大한 一毛作地帶를 二毛作地帶로 만들수 있다.
Present system of seed potato production in Korea has several weak points and consequently has difficulties ill covering annual shortage of 60,000 tons of seed potatoes. The author has all opinion that this so called "High land system" of seed potato production adopted by the Government should be replaced by the "Coastal area system" which is proposed by the author and has many advantages over present "High land system"(2). In coastal areas where enormous acreage of rice paddies are spread, mostly around the villages, the primary host plants of the vectors are found. Therefore, the only source of aphid vectors are limited to the villages. The farmer's houses scattered more sparsely also have minor importance. In the previous paper(2), the author reported that the aphid vector populations were lower in the coastalareas than at Taegwanryong where the Alpine Experiment Station for the production of seed potatoes is located. However, the number of vectors at Okku showed rather high density, where the trap was placed at the distance of 200 m from a village where peach and Hibiscus trees, the primary hosts of Myzus pesrsicae and Aphis gossypii were grown. To clarify the flight distance from the source of the aphid vectors, a trial was carried out in the Kwanghwal area, Kimje-gun, Cholla-pukro, on the western coast. 13 traps were placed at four directions and the distances between the traps were 250 m. (Fig. 1) The traps Were operated from June 21 to October 31. The results are shown in Table 1. A total of some 70 species of aphids were found, including 5 speceis of potato virus vectors. The vectors are as follows : 1. Myzus persicae (Sulzer) 2. Aphis gossypii Glover 3. Aulacorthum solani (Kaltenbach) 4. Lipaphis erysimi (Kaltenbach) 5. Macroslphoniella sanborni (Gillette) Out of a total of 12.797 aphids, 5. 187(48%) vectors were found. The trap catches at the 13 locations are shown in Fig. 2 and the numbers of the vectors at each location for each vector, except Macrosiphoniella sanborni, of which only a single individual was caught, are shown in Fig. 3-6. Number of vectors at C (3,279) (Centre of the village) is considerably higher than that at Suwon (763) ; however, EI, SI, WI and NI, where the distances from Care 250 m, showed lower numbers of vectors than that at Taegwanryong (317). The number of vectors at NI was rather than at the other 3 locations at the distance of 250m from the village. This was because C was in the southern part of the village. Consequently NI was much closer to the village than the other 3 locations of the same distance from C. Numbers of catches of the most important vector, Myzus persicae, are shown in Fig.3. The dtstribution pattern is typical except S₂ and W₃, where several farmer's houses were found. If only the rice paddies were found in these locations, the numbers of the vectors would be small as the distances increase. Numbers of catches of the other 3 vectors are shown in Fig. 4-6. From these results. the author has drawn the following conclusions : 1. The aphid vector sources at the rice paddy belt in the western coast are the villages. 2. The vector densities at the locations where the distances are 250 m from the centre of the village are lower than that at Taegwanryong. 3. The vector densities become gradually lower as the distances from the centre of village increase. However, depending on the host plant situation at each location, the vector densities are variable. These minor sources of aphid vectors may be eliminated so that seed potatoes can be grown. 4. Thus, under the direction of specialists, fields suitable for seed potato production can be found in the coastal areas.